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Albert R Young



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Charles W Mayo



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NSF Form 1225(10/99)

Bernard W Wehring

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NSF Form 1207 (10/00) Page 1 of 2

PHY - LOW ENERGY NUCLEAR SCIENCE

NSF 00-105 09/27/00

9807133566000756

North Carolina State University

0029728000

Sponsored Programs ServicesLower Level Leazar Hall - C.B. 7514Raleigh, NC. 276957514

A Measurement of the Neutron Beta-Asymmetry Using Ultra-Cold Neutrons Produced in a Superthermal Solid Deuterium Source

608,841 36 01/01/01

Physics Department

919-515-6538

104 Cox HallNC State UniversityRaleigh, NC 27695United States

Albert R Young Ph.D 1990 919-515-3124 [email protected]

Charles W Mayo PhD 1974 919-515-4600 [email protected]

Bernard W Wehring PhD 1966 919-515-4599 [email protected]

042092122

CERTIFICATION PAGE

Certification for Principal Investigators and Co-Principal Investigators:I certify to the best of my knowledge that: (1) the statements herein (excluding scientific hypotheses and scientific opinions) are true and complete, and(2) the text and graphics herein as well as any accompanying publications or other documents, unless otherwise indicated, are the original work of thesignatories or individuals working under their supervision. I agree to accept responsibility for the scientific conduct of the project and to provide therequired progress reports if an award is made as a result of this proposal. I understand that the willful provision of false information or concealing a material fact in this proposal or any other communication submitted to NSF is acriminal offense (U.S.Code, Title 18, Section 1001).

Name (Typed) Signature Social Security No.* Date

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Co-PI/PD

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Page 2 of 2

Albert R YoungS

SN

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are not d

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FA

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LA

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S*

Charles W Mayo

Bernard W Wehring

10/04/00

SECTION A — PROJECT SUMMARY

The researchers have submitted a renewal proposal for a program in low energy nuclear physics fo-cusing on a measurement of the β-asymmetry in neutron decay, utilizing ultra-cold neutrons (UCNs). Theβ-asymmetry is the angular correlation between the spin of the neutron and the emission direction of theelectron following β-decay . Measurements of this kind provide fundamental data on the charged weakcurrent form factors of the nucleon. The goal of the proposed experiment is to make use of ultracold neu-trons (UCNs) to ultimately provide at least an order of magnitude improvement in the precision to whichthe β-asymmetry is known. Such a measurement, when coupled with the ongoing Harvard-lead effort toimprove measurements of the neutron lifetime (through the use of UCNs produced in a superfluid He su-perthermal source), will provide improved values for the weak axial form factor of the nucleon, gA, and theCKM matrix element, Vud , as well as providing a sensitive tests for various extensions to the electroweakstandard model.

During the past funding period, the researchers contributed to the development of the first superthermalsolid deuterium source of UCNs coupled to a spallation target. Our prototype device was implemented us-ing the 800 MeV proton beam at the Los Alamos Neutron Science Center (LANSCE). In June of 2000, weproduced the highest density of UCNs ever reported (98

�5 UCN/cm3 in a 3.6 liter stainless steel bottle).

During the next funding period, one of the primary goals of this effort is to construct a production sourceof UCNs on a dedicated beamline at LANSCE. The proposed source will be a world-class facility, wherea series measurements of neutron β-decay and the fundamental properties of the neutron (such as limits onthe neutron static electric dipole moment) can be conducted. The existence of superthermal sources withone or two orders of magnitude greater flux makes possible the development of new applications for UCNsin condensed matter physics as well. Possible directions to explore are quasi-elastic scattering of UCNs asdiagnostics to monitor the dynamics of biological molecules or reflectrometry with UCNs to characterizenano-scale fabrication on small samples.

The contribution of the NCState group to the completion of the β-asymmetry measurement will involvethe construction, characterization, and installation of a polarizer/spin-flipper for the UCNs, measurementsof the efficiency for polarizing and flipping the spins of UCNs, measurements of the depolarization whichoccur in the guide tubes which direct the UCN to the decay volume, and the development and charac-terization of detectors necessary to measure the flux of emitted electrons following β-decay . As theβ-asymmetry measurement matures, we also hope to explore new methods for proton detection that mightbe suitable for measurements of neutron β-decay which are complimentary to the β-asymmetry .

In addition to their impact on fundamental physics issues, our proposed experiments should provideexcellent training for NCState students. Our experimental program contains an exceptionally diverse col-lection of nuclear and atomic experimental techniques, all at a scale where a PhD student can make ahuge difference to the course of the research. Furthermore, the addition of nuclear engineering facultyand students to this effort provides an opportunity for cross-disciplinary cooperation, strengthening thequality of our experimental effort and exposing our students to new opportunities for research and futureemployment.

1

TABLE OF CONTENTSFor font size and page formatting specifications, see GPG section II.C.

Section Total No. of Page No.*Pages in Section (Optional)*

Cover Sheet (NSF Form 1207) (Submit Page 2 with original proposal only)

A Project Summary (not to exceed 1 page)

B Table of Contents (NSF Form 1359)

C Project Description (plus Results from Prior

NSF Support) (not to exceed 15 pages) (Exceed only if allowed by aspecific program announcement/solicitation or if approved inadvance by the appropriate NSF Assistant Director or designee)

D References Cited

E Biographical Sketches (Not to exceed 2 pages each)

F Budget (NSF Form 1030, plus up to 3 pages of budget justification)

G Current and Pending Support (NSF Form 1239)

H Facilities, Equipment and Other Resources (NSF Form 1363)

I Special Information/Supplementary Documentation

J Appendix (List below. )

(Include only if allowed by a specific program announcement/solicitation or if approved in advance by the appropriate NSFAssistant Director or designee)

Appendix Items:

*Proposers may select any numbering mechanism for the proposal. The entire proposal however, must be paginated.Complete both columns only if the proposal is numbered consecutively.

NSF Form 1359 (10/99)

1

1

15

5

6

10

3

1

0

SECTION C – PROJECT DESCRIPTION

Contents

1 Introduction 1

2 Overview of the UCN Beta-asymmetry Measurement 3

3 Rate and Sensitivity Estimates 53.1 The Physics of a Solid Deuterium Superthermal Source . . . . . . . . . . . . . . . . . . . 53.2 A Production Source of UCN at LANSCE . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4 Systematic Uncertainties 74.1 Neutron Polarization and the RF Spin-Flippers . . . . . . . . . . . . . . . . . . . . . . . . 84.2 Depolarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.3 Neutron Polarimetry and Depolarization . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5 Detector Development 11

6 Schedule 13

7 Previously Supported Research 13

1 Introduction

The primary thrust of our proposal is the completion of an experiment, began in 1998, to measure theβ-asymmetry in the decay of polarized ultra-cold neutrons (UCNs). During the past proposal period, ourcollaboration as a whole has developed the world’s highest density UCN source, performed measurementsto test and calibrate our Monte Carlo simulations of UCN transport, initiated a quantitative investigation ofUCN depolarization, built a calibration facility to characterize our detector systems and engineered a UCNpolarizer/AFP unit in collaboration with American Magnetics Corporation. Our group has also completedan independent investigation of optically-pumped alkali metal vapors in high density, low temperatureHe-filled cells. In this proposal, we first focus on the critical projects which must be completed to beginactually taking data in our proposed measurement of the β-asymmetry in neutron decay using UCNs. Inthe detector development section we also indicate one or two possible new directions we hope to move asthe β-asymmetry experiment becomes operational. We first review our motivation for a measurement ofthe β-asymmetry using UCNs.

The angular distribution for β emission following neutron β-decay is proportional to 1 �� P � vc Acosθ,

where � P � is the polarization of the decaying parent nucleus, v is the speed of the β particle, θ is the anglethe emitted β particle makes with respect to the parent nuclei’s spin, and A is the β-asymmetry . Takentogether with measurements of the muon lifetime, the neutron lifetime, and the masses of the muon, elec-tron, neutron and proton, the β-asymmetry can be used to independently extract fundamental parametersin the charged weak current interaction of the nucleon at low Q2: the axial vector form factor of the nu-cleon, gA, and the CKM matrix element Vud . At present, the most precise value for Vud is derived fromsuper-allowed 0 �� 0 � decays, however, these studies are now limited by difficulties in the theoreticaltreatment of multi-nucleon systems[1], suggesting the use of a theoretically more tractable case such asthe neutron.

In fact, impressive progress has already been made towards improved measurements of the neutron life-time using UCNs produced in a superthermal superfluid He source[2]. Our first goal for the β-asymmetry

1

is to improve the uncertainty in the β-asymmetry of the neutron by a factor of 2 to 4 (to below 0.3%),an important step in establishing neutron decay as the definitive process from which to experimentallyderive the value of Vud . Ultimately, we hope to improve the precision of the β-asymmetry by at least anorder of magnitude, and to make significant improvements to the neutron lifetime, neutrino asymmetry,electron-neutrino angular correlation, and time-reversal (T) invariance measurements in neutron β-decay .

Figure 1: Recent values of Vud derived from mea-surements of the neutron and from 0 �� 0 decays

From an experimental perspective there hasbeen some work towards clarifying the uncertain-ties in the analysis of the 0 � 0 decays. Forexample, there has been improvement in the mea-sured decay rate of 10C to the 0 level in 10B at 1.74MeV[3], with the most recent value for the Berkeleyexperiment in agreement with previous measure-ments performed at Chalk River[4]. There are alsomeasurements, for the first time, of superallowed0 �� 0 decays in 74Rb[5]. The overall picture hasnot changed significantly, however, with the uncer-tainty in the extracted value of Vud limited by the-oretical uncertainties in the treatment of these de-cays. It is worth noting that the most recent, andprecise, measurement of the neutron β-asymmetryfrom the PERKEO II experiment yields a value ofVud � 0 � 9713 � 0 � 0014, with uncertainties compara-ble to the value of obtained from the superallowed0 �� 0 decays, of Vud � 0 � 9740 � 0 � 0010. Thevalue of Vud taken from either measurement yields a unitarity sum, V 2

ud � V 2us � V 2

ub, which is smaller thanone, with the latest neutron result over two standard deviations low (see Fig. 1)[6].

In fact, deviations of the CKM unitarity sum from one is a sensitive test for physics beyond the standardmodel. For example, Langacker and Sanker pointed out that this sum places rigorous constraints (primar-ily on the mixing angle) in minimal left-right symmetric models[13]. Ramsey-Musolf has noted that theunitarity sum also places constraints on certain classes of R-parity violating supersymmetric models, andfor these models, it is also the case that atomic parity violation measurements provide complimentaryconstraints on the same physics[14]. In addition to the unitarity sum, neutron β-asymmetry measurementscan provide direct constraints on left-right symmetric models which are comparable to the current limitsextracted from high energy probes[15], and the energy dependence of the β-asymmetry can be used to pro-vide limits on second-class currents (as was done with 19Ne)[16]. Finally, measurements of T invariancein neutron β-decay provide very useful and, for some extensions of the electroweak standard model, themost stringent limits for T and CP violation in hadronic systems[17].

Since the seminal PERKEO experiment, the β-asymmetry , together with the lifetime, has providedthe most precise value for gA and Vud from neutron β-decay [7]. There have been three measurementsof the β-asymmetry since the PERKEO experiment has been performed (see table I), and the situation isfar from satisfactory. Each of these experiments is roughly at the 1% level, but the agreement betweenthese experiments is poor. The resulting combined limit, taken from the Particle Data Group, is alsoonly at the 1% level, reflecting a possible underestimate of the relevant systematic uncertainties in thesemeasurements[18]. Because all of the previous neutron β-asymmetry measurements were performed usingcold neutron beams at reactor facilities (with relatively high backgrounds), we believe there is an excitingopportunity to pursue a measurement of the β-asymmetry using UCNs produced at a spallation source.

UCNs are neutrons whose speeds are smaller than about 8 m/s, making it possible to store them inmaterial bottles. There are at least two advantages associated with the use of UCNs produced at a spallationsource to measure the β-asymmetry : UCNs can be produced with essentially 100 percent polarization,

2

and the β detection backgrounds are very small.Because the energy associated with the neutron spin (Emag �� µ � B) can be made much greater than the

UCN kinetic energy, UCNs can be polarized by passing the neutrons through a strong solenoidal magenticfield. One of the spin states is repelled from the strong field region, and lacks sufficient kinetic energyto overcome the magnetic potential barrier, whereas the other passes through the magnetic field regionunhindered. Although the UCN may subsequently depolarize through some interaction with the walls, wehave performed measurements that already place an upper limit on the average depolarization experiencedby the UCN of about 0.15%. The fraction of UCN which are have depolarized will be measured inany case (see subsections 4.1 through 4.3 for more details). Perhaps equally important, the experimentalenvironment of our spallation source of UCNs is quite different from a reactor guide hall. We plan tobriefly direct the proton beam onto our spallation source once every 10 seconds. Data can be taken withthe proton beam off, reducing the backgrounds by at least an order of magnitude from those encounteredin the reactor experiments.

Date Measurement β-asymmetry

1988 PERKEO I (ILL)[7] � 0 � 1146 � 0 � 00191991 Gatchina[8] � 0 � 1116 � 0 � 00141995 ILL-TPC[9] � 0 � 1160 0 � 00151997 PERKEO II (ILL)[10] ! 0 " 1189 # 0 " 00121997 Gatchina[11] $ 0 % 1149 & 0 % 00142000 PERKEO II (ILL)[12] ' 0 ( 1189 ) 0 ( 0008

Table 1: Recent Measurements of the neutron β-asymmetry

One of the accomplishments of our col-laboration in the past few years was theconstruction of a prototype source of UCNswhich utilizes the superthermal productiontechnique in solid deuterium. The results ofthis project are exciting: we have recentlyproduced the highest density of trappedUCNs to date: 98 * 5 UCN/cm3 in a 3.[20].This should be compared with the previousrecord of 41 UCN/cm3 measured at the In-stitut Laue-Langevin (ILL) in Grenoble[21].The densities produced in our prototype source were essentially still limited only by beam current (wewere limited by administrative caps placed on the beam current we could direct at our target), with onlya suggestion of heating of the solid deuterium even at the higher beam currents than those we plan to usein our production source. Ultimately, a high flux, superthermal source of UCNs opens, in addition to ourproposed program of research on neutron beta-decay, possible applications in nanoscale fabrication andbio-physics.

We have assembled a collaboration of over 30 researchers from 11 institutions (A. Young and T.Bowles, co-spokesmen). The collaboration includes NSF-funded university teams at NCState University,Caltech and Virginia Tech, as well as a substantial DOE-funded team at Los Alamos and groups at ILL, thePetersburg Nuclear Physics Insitute (PNPI), and several groups in Japan (see the Section D–ReferencesCited for a tabulation of the collaboration members). The experiment as a whole recieved the highestrecommendations directed towards any new research project in medium-energy physics, by a review panelof the National Science Advisory Council convened in 1998. We have also passed, in late April of 2000,a technical review necessary for the release of funds to begin construction of our production source at theLos Alamos Neutron Science Center (LANSCE), and have identified an appropriate proton beam line andexperimental hall to perform our measurement.

2 Overview of the UCN Beta-asymmetry Measurement

The proposed measurement should be performed at a spallation target on a dedicated proton beam lineat LANSCE. The experimental strategy will be similar, in many respects, to the 19Ne β-asymmetry ex-periment recently conducted at Princeton[22] (see Fig. 2): essentially 100 percent polarized UCN’s areintroduced to a “UCN bottle” arranged along the axis of a 1.0 T, solenoidal magnetic field. The inner wallsof this UCN bottle are roughened near their ends, which causes the UCN’s to diffuse slowly out of the de-

3

Polarizer /+

Instrument

Li-doped Epoxy6

To UCN Flux and/orPolarization Monitor

Diamond Film

Decay VolumePlastic Scintillator

Light Guides(to PMTs)

MWPC

To UCN Sourcep,

J-

Emitted Betas SpiralAlong Magnetic Field Lines

Roughened Surface

AFP

e. -

Solenoid Magnet (1.0 T)

Figure 2: Schematic diagram of an apparatus to measure the β-asymmetry of the neutron using UCN’s

cay volume with an average residence time of roughly 5 seconds[19]. UCN’s which undergo β-decay emitelectrons which spiral parallel or antiparallel to the solenoid field, and are ultimately counted in detectorarrays situated beyond the ends of the UCN bottle. After leaving the decay volume, the UCN’s are eitherdetected in polarimeters arranged at the ends of the solenoid, or are captured on 6Li-doped epoxy walls.

As mentioned in the Introduction, UCN’s are polarized simply by passing them through a 7T solenoidalmagnetic field. This population of polarized spins can be flipped using an adiabatic fast passage (AFP)geometry permitting the experiment to measure the decays of UCN’s polarized parallel or anti-parallel tothe holding field in the decay volume. The measurement itself is accomplished by measuring decay rateswith the neutron spin oriented first parallel and then anti-parallel to the magnetic field axis and then byforming ratios of the detector responses to extract the β-asymmetry .

The North Carolina State University group is composed of A. R. Young (PI), C. Mayo, B. Wehring,postdoctoral fellow D. Smith, Chen-Yu Liu and Seth Hoedl (Princeton graduate students, one of whomhas elected to continue and obtain her PhD working on this project) and S. Wang (an NCSU nuclear en-gineering graduate student). In fact, D. Smith has just taken a post at SLAC, making necessary a newhire to fill his position. This group will be assist in the development of the production source of UCN atLANSCE, primarily by providing engineering expertise in the design of the spallation target and associ-ated moderation of the fast neutron flux, as well as investigation of the physics of the UCN converter. Ourresponsibilities also include the development of the polarizer/AFP spin-flipper, measurements of depolar-ization of UCN on material surfaces, detector development work (quantitative studies of backscatter fromdetector surfaces and the investigation of proton detector geometries) and simulation/analysis of the ex-perimental results. Our expertise is particularly well-suited to the evaluation and control of the systematicuncertainties characteristic of β-asymmetry measurements and nuclear engineering design questions. Oneof the explicit suggestions by the technical review panel was, “More essentially full time staff are neededin leadership positions and at the postdoctoral level.” At present we plan, for the next two to three yearsonly, to expand our UCN effort to include two postdoctoral fellows and one more student.

Our collaboration has been very active as a whole. In addition to our source development activities

4

(lead by the team at Los Alamos), the Caltech group has developed a calibration facility for our beta de-tectors and has redesigned the decay spectrometer from our original design to utilize a superconductingsolenoid. The details associated with the design of the spectrometer solenoid are essentially established,and the overall cost is within our original guidelines. The Virginia Tech group has developed a hydro-gen free diamond-like film that is very promising for limiting depolarization and the UCN losses due toupscatter, absorption and transmission through the coating.

3 Rate and Sensitivity Estimates

For our experiment coupled closely to a solid deuterium source, the projected decay rate in our “bottle” isabout 118 Hz. This estimate is the result of detailed modeling of our source, the guides passing throughour polarizer/AFP spin-flipper unit, and the decay spectrometer. [19] Incorporating the sensitivity factorsdiscussed in section 4 (and using the experience of the previous 19Ne and neutron β-asymmetry experi-ments) we expect to require about 2 / 2 0 108 decays to reach a statistical uncertainty of 1 / 8 0 10 1 3 in theasymmetry. We can reach this with 30 good days of running, after accounting for our expected detectionefficiency and a fiducial volume cut. Using our collaborations’ previous experience with the LANSCEfacility as a guide, this will require roughly 40 days of beam time. Because we plan to have a dedicatedbeamline operating continuously for roughly nine months out of the year, this goal seems consistent withavailable beam time. Indeed, our current plan is consistent with a continually improving limit over thecourse of 1 - 2 years, ultimately producing statistical uncertainties below the 1 0 10 1 3 level. We expectthat systematic uncertainties, in part stemming from uncertainties in detector response, will ultimatelylimit the precision of the proposed measurement.

These projected decay rates are derived from a very conservative strategy. Our Monte Carlo projec-tions for the production source are based entirely on the performance we have already achieved with ourprototype source, with no major modifications to the design of the spallation target or fast/thermal neutronmoderation strategy. In fact, we believe there are several avenues that one might pursue to improve on ourcurrent design.

3.1 The Physics of a Solid Deuterium Superthermal Source

We have made significant progress in the past funding period in understanding the physics of a superther-mal SD2 source. A schematic of our prototype source is depicted in Fig. 3A. This work is detailed in thesection on the Results from Prior NSF Support, so only a brief outline will be presented here, to introduceavenues of investigation during the next funding period. One Princeton student in our group, C.-Y. Liu, iswriting her Ph.D. thesis on the the physics of our superthermal source. She should finish this work at theend of the second year of our renewal period.

The physics of UCN production in a SD2 source were first discussed by Golub and Boning[23] in 1983.The basic production mechanism is dominated by “downscattering” cold neutrons through the creation ofa phonon which carries off almost all of the energy of the scattered neutron. For SD2 at 5 K, Golub’swork provides quite accurate predictions for the production. Once the UCNs are produced, however, theymust escape from the solid deuterium in order to be useful. Our work in the past two years has providedinsight into the various mechanisms which eliminate UCNs after they are produced in the SD2 converter.In addition to the previously recognized mechanisms of nuclear absorption in the deuterium (or hydrogencontamination) and upscatter, UCNs can upscatter through collisions with para-deuterium in the SD2 ma-trix (SD2 is a molecular solid). This results in an essentially temperature independent loss mechanism forthe UCN which is roughly two orders of magnitude more rapid than nuclear absorption.[24] We developedan experimental approach which allowed us to control and precisely measure the para-deuterium concen-tration, permitting us to quantitatively explore it’s effect on UCN lifetimes (see the section on PreviouslySupported Research for more details).

5

SD2

Pump

35 literstorage volume

Input valve Exit valve

Top

3.3 m

1 m 9.5 m (not to scale)

UCNout

protons in

100

200

300

400

20 40 60 80 100 120 140 160elapsed time (s)

Storage Volume Filling

UCN/cm

3

L2

iquid N2

B3

e reflector

S4

olid D2

75

7 K poly

T6

ungsten

V7

acuum chamber

58N8

i coated stainless guide

S9

hielding

U:

CND;

etector

C<

old neutron detector

A=

) B)

Figure 3: A) The prototype source. B) The geometry modeled in our Monte Carlo studies of the productionsource, and (inset) the resultant stored UCN density in the source storage volume. These densities resultin a mean decay rate of 118 Hz in our modeled β-decay experiment

A remaining issue, which we will hopefully investigate in some detail in the next funding period, isthe effect of different growing techniques on the mean free path for elastic scattering of UCN in the SD2

crystal. We have seen modest effects (on the order of 30% or so) in the UCN production when we havegrown deuterium crystals by freezing from a liquid state versus freezing directly from D2 vapor, however,these studies were conducted primarily with 33% para mixtures, and probably with poor temperaturecontrol of our solid. More revealing and quantitative studies are now possible with our improved D2

para-to-ortho conversion system.Another approach which we find quite exciting is to implement a solid oxygen (in the ferromagnetic,

α phase) source of UCNs. This material has several advantages over deuterium: it has only one molecularrotational species (because both abundant, naturally-occuring isotopes have nuclear spin 0), it can beeasily and cheaply produced in very pure form, and it has an absorption lifetime about a factor of 5 longerthan solid deuterium. These advantages are partially offset by a lower production rate from the phononsin solid oxygen. However, solid oxygen has a previously unexplored UCN production mechanism atlow temperatures: downscattering through the production of magnons, or electronic spin excitations[25].Magnon production may more than offset the difference in production rates between solid deuterium andoxygen, making oxygen a very intresting possibility. Because naturally occuring oxygen has an extremelysmall incoherent scattering length, it may also be possible to create quite thick oxygen sources as well.

The two physics issues just discussed: understanding the influence of the crystal growth process on theUCN yield and assessing the possiblities of a solid oxygen source, both can be explored using our presentprototype source. Ultimately it may be necessary to cool the oxygen source to 2K to derive the full benefitfrom the magnon degrees of freedom, requiring modest modifications to our current cryostat.

6

3.2 A Production Source of UCN at LANSCE

One of the largest action items for our collaboration is the construction of a production source of UCN.At present, our proposed source is based on a small variation of the prototype device depicted in Fig. 3Aand discussed in Section 7. Essentially we plan to widen the guide tube containing the SD2 to about 20cm, and, after a meter of vertical extraction, couple it to a large, LN2 cooled storage volume. At present,widening the guide and cooling the storage volume are the only substantial changes we propose in oursource. The physical scale of the spallation target and overall design are essentially unchanged.

An area where we have placed considerable effort is the Monte Carlo simulation of our prototypegeometry. To this end we have made measurements of a variety of UCN guide tube geometries usingthe test UCN beam at ILL, in collaboration with P. Geltenbort, and used these to evaluate and refineour simulations of UCN transport. It is clear from these simulations that we have a reasonably solidunderstanding of our UCN fluxes and can simulate the transport of UCN through complicated guide tubeconfigurations at roughly the 20% level (comparison with Monte Carlo is exhaustively detailed in ourtechnical review document[19]). The results of our simulations of the production geometry are depicted inFig. 3B, where the inset graph depicts the density of UCN in the source storage voume. The resultant decayrate in the beta spectrometer is predicted to be 118 Hz for our planned experimental geometry. We haveassumed a 2% para fraction, 0.4% HD contamination, and 5 K source temperatures in these simulations,and routinely achieve these conditions or do slightly better.

There are a number of areas where gains might be made through a careful investigation of the engi-neering of our source. In particular, we can investigate changing the dimensions and composition of thetarget; for example, we are in the processes of evaluating the use of a Pb target vs. the W target now in use,primarily because of the Pb’s smaller neutron absorption cross sections. We can vary the composition andthickness of the neutron moderators; at present, these are polyethylene inside a Beryllium “bucket.” Wemight also vary the configuration of the converter (SD2) around the spallation target; cylindrically sym-metrical geometries where the deuterium encases the target should make optimal use of the cold neutronflux. Investigating these ideas will require systematic studies using the Monte Carlo code, MCNP. Severalmembers of our group (C. Mayo, B. Wehring) have extensive experience in engineering fast and thermalneutron moderating geometries, and should be able to contribute in a significant fashion to our efforts torefine our production source. The need for support in this area is particularly pressing because our previousMonte Carlo specialist, Los Alamos staff member, Roger Hill, is involved in another project and now onlydevote a small fraction of his time to our effort.

In addition, we plan to work with the Los Alamos team to continue to refine the ortho/para converter,to verify that we can maintain deuterium with less than 0.4% HD contamination over substantial periodsof time, and to investigate the effects of various techniques of crystal growth. This effort will requiresignificant manpower stationed at Los Alamos. Thus we propose to support one postdoctoral fellow whowill be stationed full time at Los Alamos and will assist in the source development, depolarization studiesand other aspects of the Los Alamos effort as needed.

4 Systematic Uncertainties

The central issue in accurately determining the β-asymmetry at the percent level and below are the system-atic uncertainties associated with the measurement. They are numerous and should all be reduced and/orcharacterized at levels below 0.1%. As mentioned above, the angular distribution for neutron β-asymmetryis proportional to 1 > v

c ? P @ Acosθ. Thus our task is to determine vc , A P B and cosθ to sufficient precision for

each observed decay. From this information, the β-asymmetry , A, can be extracted.Our strategy adopts various elements from the many previous measurements of the β-asymmetry of the

neutron and 19Ne. We observe the neutron decays in a strong magnetic field, which serves to provide 4πcollection efficiency for the emitted electrons (because they are forced to spiral along the field lines until

7

they strike a detector face, see Fig. 2). Another advantage is that this geometry yields a precisely definedaverage value, C cosθ D =0.5 for the measured decays (this “geometry factor” requires a small correctionfrom Monte Carlo simulations of the experimental response, see subsection 4.2).

The β-asymmetry is then determined by the ratio of the signals measured in each detector, with theneutron spin first parallel and then anti-parallel to the magnetic field axis:

R E N1 F N2 GN1 H N2 IKJ (1)

where N1 I is the number of events recorded which first strike the left-hand detector (detector 1) with theneutron spin pointing parallel to the magnetic field ( L ), etc... Ignoring, at present, the contributions to thecount rate due to backgrounds, the asymmetry is given by:

A M 1NP O N cosθ OQP v

c RS

R T 1UR V 1 W (2)

The advantage of this formulation is that this ratio eliminates the detector efficiency differences betweenthe two detectors and fluctuations in the neutron density to first order (to levels well below 0.1% ).

The remaining systematic uncertainties can be broadly divided into three categories: those concerningknowledge of the A) neutron polarization and neutron spin dependent effects, B) electron detection, andC) backgrounds. The backgrounds have been measured using a coincidence scheme, and should be a fewpercent of the full count rate. These backgrounds, producing signal-to-background ratios similar to thoseencountered in our measurement of the 19Ne β-asymmetry and an order of magnitude smaller than thoseencountered in reactor experiments, are at acceptable levels for the proposed measurement. Thus in whatfollows, we discuss aspects of categories A) and B).

4.1 Neutron Polarization and the RF Spin-Flippers

As mentioned previously, the method utilized to polarize UCNs is straightforward and should be extremelyeffective. The efficiency of polarization depends only on the maximum velocity of the UCN incident onthe high field region and the maximum field strength in the polarizer region. We have simulated our sourcegeometry to ensure that effectively all UCN leaving our source storage volume have velocities at or belowthe cutoff velocity for 58Ni, ensuring 100 percent polarization after traversing the 7 T field.[19]

In order to determine the spin-dependence of the decay rate, we must be able to flip the direction of theneutron spins. We can accomplish this in two separate ways (1) reverse the direction of the holding field,(2) flip the UCN spins externally using an AFP spin flipper. There are significant advantages to having twoseparate spin-flip techniques, since this permits us to separately investigate systematics associated with thealignment of the magnetic field and systematics associated with the operation of the rf resonators. TheAFP geometry, moreover, gives us the capability of more rapidly reversing the spins, improving our abilityto isolate effects associated with the time-variability of backgrounds.

The AFP procedure involves passing the UCN through a magnetic field region where the longitudinalfield, Ho, is very gradually decreasing, with a field of 1 T at the center of the AFP volume. An r.f. field,H1, is generated within this volume which rotates in the plane orthogonal to Ho at the spin precessionfrequency of the neutron (ω X 1 W 9 Y 108 rad/sec) in a 1 T field. Abragam[26] provides an upper limit forthe depolarization during an AFP procedure, which we can use to place a criterion on the fields in ourgeometry. If we wish to ensure that less than 0.1 percent depolarization occurs then:

∆PP Z

v [ ∇Ho

γH21

\ 10 ] 3 ^ (3)

where we have assumed that we begin with 100 percent polarized neutrons, and γ _ 1 ` 9 a 108 rad/sec b T.Given speeds of our UCNs no greater than 7 m/s and a maximum gradient of about .0067 T/m, this places

8

a lower limit on the magnitude of H1 of 5 G. We note that this criterion is in practice quite stringent. Inanother AFP geometry that the Princeton nuclear/atomic group helped assemble and test to flip the spinsof 3He atoms, this criterion yields an upper limit on the depolarization about 1 order of magnitude larger(∆P c P d 10 e 2), but the depolarization has been measured for this case to be smaller than 0.1 percent[27].The excellent performance of this much less exacting geometry gives us a measure of confidence that ourcarefully tailored field geometry will provide us with our target polarization and spin flip efficiencies.

We plan to use a high-pass, “bird-cage” resonator, similar to those employed on medical MRI imaginginstruments to produce our r.f. fields[28]. These resonant devices produce very homogeneous fields, andcan be coupled to the r.f. to produce rotating fields to make more efficient use of the available r.f. power.A 16 conductor birdcage gives excellent r.f. field uniformity over about 70 percent of its inner volume,which is more than adequate for our application[29]. We constructed an 8 conductor resonator whichcould accomodate a 6 cm beam pipe, similar to the proposed geometry, and inserted this resonator intoa cylindrical conducting shield. It was determined that the required field strengths can be achieved withreasonable r.f. power and that the r.f. fields decay very rapidly outside of the resonator, falling roughly anorder of magnitude every 8 cm one moves away from the resonator’s edge.

The engineering for the static magnetic fields is now complete for the Polarizer/AFP spin-flipper, andconstruction has started with our industrial partner in this project, American Magnetics, Inc. We antici-pate delivery of the completed magnet unit in February or March of 2001 to NCState, where we will mapthe static magnetic fields within the UCN guide-tube volume using an NMR, FID magnetometer (thesemeasurements are similar to those required to establish field homogeniety in the 19Ne β-asymmetry mea-surement). We will also construct, tune and map the fields of a resonator, and then ship the magnet on toLos Alamos for polarization/depolarization tests during the summer of 2001. This device and polarizationand spin-flipping efficiency studies will be the primary responsbility of a postdoctoral fellow and graduatestudent team during the next year of development work.

4.2 Depolarization

Although we have considered a large variety of depolarization processes, we have not yet found such aprocess which will result in significant depolarization for our planned geometry. In particular, depolariza-tion due to magnetic field inhomogenieties[26] and depolarization due to wall collisions in the presence ofmagnetic field gradients[30] should both produce depolarization smaller than 1 f 10 e 4 for our geometry(we have actually tailored the fields along the path of the UCN through our experiment to ensure this isthe case). These processes are discussed in great detail in our technical review document[19].

Another possibility is for the UCN to depolarize due to some spin-dependent interaction with thewall materials. A large effort in our collaboration is dedicated to assessing the magnitude of materialdepolarization and to producing spin-preserving coatings. To this end we are developing a hydrogen-free diamond film coating utilizing laser ablation deposition (the primary responsibility of the VirginiaTech group). These coatings have been shown to have characteristic cutoff velocities of about 7 m/s,corresponding to a material potential of about 260 neV, are chemically inert, electrical insulators (noconduction electrons) and have essentially no nuclear or electronic spins in the consituent nuclei to coupleto the neutron spin and cause depolarization.[31]

We expect the relaxation time for UCN’s in our diamond film-coated neutron bottle to be much longerthan roughly 104 seconds, our worst-case estimate of the relaxation time for a wall covered with a thickcoating of some paramagnetic species[32]. Since the residency time in our decay bottle is only 5 seconds,this results in depolarized UCN fractions less than 0.05%. At present, our experimental studies of depo-larization at ILL provide limits for amorphous carbon and copper which are consistent with an averagedepolarization less than about 0.15% (see the section on Previously Supported Research), which shouldbe adequate for our first proposed measurement. Since we view these measurements as only establishingupper limits for depolarization, and we expect our diamond films to be superior to these materials, and we

9

plan to monitor the fraction of UCN which are depolarized, we feel this experimental challenge is underreasonable control.

4.3 Neutron Polarimetry and Depolarization

Although we expect the absolute polarization for UCN in our decay volume to be above 99.9%, one of themost notable features of this experiment is our ability to measure deviations from 100% neutron polariza-tion better than 1 part in 103. We can accomplish this in several different ways. The most straightforwardmethod is to close the ends of our bottle and directly measure the depolarized fraction which accumulatesas a function of time. A depolarization probability per bounce of only 2 g 10 h 6 (resulting in depolarizationfractions of less than .04% in our β-asymmetry measurement) yields about 80 depolarized UCNs after 15seconds of storage (using a UCN holding time of 30 seconds in the closed bottle). Measuring these 80UCNs over a characteristic time of about 20 seconds yields a signal-to-background ratio of at least 20to 1 in our UCN detectors, and provides adequate sensitivity in a single, roughly 1 minute measurement.We plan to install pneumatic valves at the ends of our holding bottle and in the entrance guide which willpermit us to perform these measurements (see Fig. 4) at regular intervals during our runs. Because we planto measure the depolarized fraction of UCN, even a crude upper limit should be sufficient. We estimatethat systematic uncertainties, stemming primarily from our ability to reliably model this geometry, shouldlimit the overall precision of a measurements of the depolarized flux to about 20%, which is more thanadequate for our first experimental determination of the β-asymmetry .

Polarizer

AFP

TTo UCN Source

3

UCN detectorSwitcher

To UCN source

1

Si

2

Valve

Valve

Vj alveValve

Figure 4: A possible method for measurement of thefraction of depolarized UCNs: Step 1, close valves 1and 2; Step 2, introduce UCNs and then close valve3; Step 3, wait for 15 seconds and then open valve3, directing “right” spin UCNs to the detector; Step4, turn on AFP and count depolarized UCNs

To perform a direct test of the polarizer and AFPspin-flipper working together, one can attempt tomeasure the transmitted fraction of UCNs through a“crossed” detector-analyzer configuration. For ex-ample, one might pass the UCNs through the po-larizer and AFP/spin-flipper unit, and then directthem, with a switcher valve, either to a He3 UCNdetector before a second analyzer magnet or to adetector located after a second analyzer magnet.The ratio of the signal obtained with UCNs flow-ing through the analyzer magnet (when no UCNs atall should be observed if there is no depolarization)to the primary flux measured before the analyzeryields a measure of the polarization efficiency forthe polarizer/AFP spin-flipper unit. Experiments ofthis kind can be performed either with our sourceor at ILL, and will be quite sensitive to unpolar-ized/depolarized UCNs. For example, in either ge-ometry we should be able to pass more than 20,000UCN/sec through our standard 8 cm diameter guidetubes into such an experiment, so after a few seconds adequate limits should be obtained.

One of the highest priorities of our experimental effort is to quickly develop a simple test geometry,using our prototype source, to evaulate the depolarization rates in diamond film-coated guides and measurethe efficiency of our polarizer/spin-flipper. We can perform these studies using a geometry similar to thatin Fig. 4, with a guide tube placed beyond valve 3 instead of the decay volume. To this end, the necessaryUCN “switcher” valves are now being fabricated at Los Alamos, a second large bore 7 T analyzer magnetis already available, the diamond-coated guides should be produced this winter at Virginia Tech, and thepolarizer unit should be operational when proton beam is available at LANSCE in June of 2001.

Finally, when we actually measure the β-asymmetry , it should be possible to essentially “pulse” the

10

UCNs entering the experiment by admitting them for roughly 10 seconds to achieve the limiting density,and then shutting off the flow (at the source) and monitoring the time-variation of the β-asymmetry signal.Any decrease of the absolute value of the β-asymmetry over time would indicate depolarization is occuring.Although studies of this kind may lengthen the duration of the experiment by roughly a factor of two, theymake it possible to monitor depolarization in situ.

5 Detector Development

Beta detection: We have made quite significant progress in our detector development effort over thepast two and a half years. The Caltech group joined our collaboration and took responsibility for thedevelopment of a calibration facility which provides a collimated electron beam in two energy ranges:from 150 keV to 1 MeV and from 10 keV to 80 keV. A Helmholtz coil spectrometer provides a roughly0.2% energy resolution. Caltech will also produce the final detector geometry which will be used for betadetection in our β-asymmetry experiment, which is at present a gas proportional counter mounted in frontof a plastic scintillator detector (this detector geometry is discussed at some length in the document forour technical review[19]). The role of the NCSU group is to develop a prototype of the plastic scintillatorgeometry (essentially already built, see the section on Previously Supported Research), characterize thelinearity and response function of this detector, and to attempt to understand the electron scattering fromthe face of this detector (“backscatter”). The scattering studies on our plastic scintillator should lead tosystematic backscatter studies of beryllium, aluminum and silicon as well. This detector developmentprogram and the quantitative backscatter studies are part of the thesis of Princeton student Seth Hoedl,who will pass the torch onto an NCState student during the next half year.

Our focus on the backscatter arises from our need to reduce, as much as possible, a systematic errorassociated with missed backscatter events. In an event of this kind, the electron scatters from the face of onedetector without depositing energy above the detector threshold, and then traverses the spectrometer and isultimately counted in the detector at the opposite end of the spectrometer. The multiwire gas proportionalcounters (in addition to defining our fiducial decay volume and providing a coincidence signal for betas tominimize background) permit us to identify events which backscatter from the plastic scintillators but donot deposit energy above the plastic scintillator threshold.

To minimize this effect, we hope to implement a graded magnetic field geometry in which the mag-netic field is uniform within the decay region, and then smoothly decreases to about half its central valuenear the detector face. This effect (utilized with success in the 19Ne β-asymmetry experiment and in mea-surements of β spectra of 35S and 14C by a Berkeley/Argonne collaboration[33]) reduces the pitch angleof the spiraling electron trajectories as they enter the detector face, suppressing backscatter. Also, someelectrons which do backscatter are “mirrored” by the field geometry and directed back onto the face theappropriate detector. Simulations of our detector geometry using a graded magnetic field indicate that,with the multi-wire proportional counters to help identify backscatters, the missed backscatter fractionshould be below 0.075%.

We note that this mirroring effect can lead to another systematic error, associated with UCN decayswhich occur in the field expansion region, where the emitted electron is mirrored back onto the detectorface, washing out the β-asymmetry . In our experiment, the walls of the field expansion region are coatedwith UCN absorbing, Li-loaded epoxy. This results in a very low effective UCN density in the fieldexpansion region, and a net washout of the β-asymmetry less than 0.1 percent.

Ultimately, however, one must correct one’s measurement for the backscatters which are missed evenby the multiwire gas proportional counters. This requires a detailed Monte Carlo treatment of electrontransport within low Z materials, where multiple scatter effects should be extremely important. To evaluatethe current reliability of the available Monte Carlo codes (GEANT 4.0[34], EGS4[35], EGSnrc[36], ITS3.0[37], and PENELOPE[38]) we first undertook a thorough search of the literature for low Z electron

11

backscatter data and tested the Monte Carlo codes EGS4, EGSnrc, ITS 3.0 and PENELOPE against thisdata. The result of this study are the observations that: (1) Except for Be, the general agreement withexisiting data is roughly at the 20 percent level (for Be the discrepancies between measurement and modelcan be as great as 40 percent), and (2) there are very few cases in which there is adequate scattering datain the energy range from 20 keV to 1 MeV. In particular, we found doubly differential (in energy andangle of the backscatter electrons) studies only for Al and Si at incident electron energies between 30 and40 keV.[39] We propose to systematically measure backscatter spectra and angular distributions over arange of incident electron energies from 20 keV to 1 MeV. To this end, we have already constructed anapparatus to perform these measurements, and will present preliminary measurements at the DNP meetingthis October.[40]

We note that these measurements may serve to improve the approach to modeling electron transport, asthe backscatter process is a stringent test of the performance of these codes (especially for low Z materials).Essentially all of these codes treat solids as a collection of free atoms, and ignore, for the most part, theeffect of embedding the atom in a solid state. At least one study, however, indicates that these densityvariations can have a modest influence on the scattering process, especially on the low energy elasticscattering cross-sections[41]. With the ability to extensively characterize the backscatter from variousmaterials, we may be able to more thoroughly investigate these issues.

Proton detection: An interesting direction for the future is to develop low energy proton detectioncapability. With this in hand we could immediately measure the neutrino asymmetry and the electron-neutrino angular correlation using our spectrometer. Several measurements of the neutrino asymmetry andelectron-neutrino angular correlation are being planned for cold neutron beams[42], since these measure-ments are also sensitive to the axial vector form factor and various extensions to the standard model[6, 43].Because the product of (decay rate) k (beam time) we can achieve should be comparable to the reactorexperiments, and because we expect extremely small backgrounds, superior detector calibration facilities,and very small uncertainties in the neutron polarization, studies using UCNs in our spectrometer shouldbe quite competitive with planned measurements using cold neutron beams.

Perhaps the most promising technique for proton detection is being investigated by the group ofDubbers[44], for a geometry very similar to ours, in which they plan to measure the neutrino asymme-try (the correlation between the neutron spin and the direction of emission of the neutrino, which is relatedby momentum conservation to the direction of emission of the proton). They have tested large area (110cm2), stand alone, carbon foils with a layer of MgO on the back (post acceleration) side, with a total thick-ness of 40 µg/cm2. The foils are used by placing an accerating grid in front of the foils to pre-accelerate theprotons (with maximum energies prior to acceleration of about 751 eV) to about 20 keV. Protons strikingthe foil emit, on average, 6 to 8 secondary electrons from the opposite face of the foil, which can thenbe post-accelerated to 40 keV and detected in our wire counters. Protons detected in delayed coincidencewith the prompt beta particles can then be used to determine the neutrino asymmetry (in polarized UCNs)and the electron-neutrino angular correlation (where the UCN do not have to be polarized). Note thattransport simulations of the beta-particle (emitted during neutron β-decay ) through these extremely thinfoils in our graded magnetic field geometry indicate that the corresponding backscatter fraction is below0.1%, and should not be a limiting factor in the first angular correlation studies we perform using protons.

We plan to investigate this detection technique as well as the possibility of multi-step avalanche coun-ters to detect the recoil protons. The carbon foils have the advantage that they can also be used to confineUCNs, and may ultimately lead to a new methods, analogous to the T invariance measurements in theβ-decay of 19Ne, for UCNs[45].

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6 Schedule

We should note that our present, very agressive schedule depends on the construction of essentially threelarge, mostly independent pieces of equipment: the UCN source, the polarizer/AFP spin-flipper, and thespectrometer. The first two of these are fully funded and polarizer construction is actually underway.Caltech has taken responsibility for the spectrometer, and an engineered design is now complete. The timescales for completion of these projects is that the polarizer should be complete and installed by June of2001, the spectrometer should be fabricated and detectors complete in January to February of 2002, withthe source planned to come on line in mid- to late 2002. A detailed schedule is presented in our technicalreview document[19].

7 Previously Supported Research

Introduction: A. Young and T. Bowles are co-spokesmen for a collaboration assembled in late 1997 tomeasure the neutron β-asymmetry using UCNs at LANSCE. This proposal is a renewal of work begununder grant 9807133, “Low Energy Nuclear Physics Using the Princeton Cyclotron, Lasers, and Ultra-Cold Neutrons” for $667,000. We also obtained, while at Princeton, Major Research Instrumentation grant9977557, “Development of a Polarizer/Adiabatic Spin-Flipper for Ultra-Cold Neutrons,” for $155,000 toprovide an essential instrument for our measurement of the β-asymmetry . Because our group has movedand the support for our effort has changed, we felt it might be helpful to outline who was supported on thisgrant during the last period and how the group has changed. Our group was based at Princeton for the pasttwo and a half years, and was composed of A. R. Young, D. Smith (post-doctoral fellow), and C.-Y. Liuand S. Hoedl (graduate students). We have recently moved to North Carolina State University (NCState).One Princeton student is remaining with the project and the other is finishing a detector devlopment taskbefore finishing his thesis on another project. D. Smith has taken a staff position at SLAC, and we seeka new hire to replace him, as well as an additional post-doctoral fellow, for which there is some supportfrom the NCState physics department as well. We plan to have four graduate students associated withthe project during the next period, C.-Y. Liu, S. Hoedl, S. Wang, and one other NCState physics graduatestudent. In addition to this, NCState nuclear engineering faculty C. Mayo and B. Wehring have joined ourgroup, with interests in superthermal source development and possible solid state applications for UCNs.

We have also worked with a number of undergraduates, with Princeton students R. Krumholz, U.Pesavento, and M. Kesden doing junior research projects and Umberto Pesavento doing a senior thesisproject on UCNs.

The Solid Deuterium Superthermal Source: the primary activity of our group in the past two and ahalf years has been the development of the solid deuterium (SD2) superthermal source of UCNs at LAN-SCE. The development of this source was coordinated by C. Morris at LANL, with strong participation byour group and contributions from a number of other members of the β-asymmetry collaboration, includinggroups at Caltech, ILL, PNPI and the Kyoto University Reactor Research Insitute (KURRI). Our groupprovided the initial funds to construct the cryostat and was responsible for the subcontracting fabricationof most of the cryostat parts prior to assembly at Los Alamos. We also provided the only full-time ex-perimental personnel associated with the SD2 UCN source project at Los Alamos (D. Smith) for its firsttwo years, and participated vigorously in the exploration of the physics of the solid deuterium source (seebelow).

The prototype source is depicted in Fig. 3A, and consists of a tungsten target, placed within a fastneutron flux trap of Be held at 77 K. A sheet of polyethylene, resting on the tungsten target at 77 K,and a cylinder of polyethylene wrapped around the SD2 cryostat at 5K serve as our primary cold neutronmoderators. Within the 5K cryostat, a piece of SD2 rests in a 58Ni guide with a cross-sectional area 50cm2. An 800 MeV proton beam is directed, for up to a few seconds, onto the target, producing roughly

13

18 high energy neutrons per proton. These are moderated and pass through the SD2 converter, producingUCNs which are guided upwards to our stainless steel bottle or to a UCN detector.

Our investigation of the physics of SD2 superthermal sources led to new insight into the influenceof the presence of para-deuterium in the SD2 matrix. Because D2 is a homonuclear molecule, there arestrict selection rules on the molecular rotational spectrum, with para-deuterium (molecular spin, I l 1)only exhibiting rotational states with quantum numbers J l 1 m 3 m 5 monpnpn and ortho-deuterium (I l 0 or I l 2)exhibiting J l 0 m 2 m 4 monpnpn Conversion between the para- and ortho-species is essentially negligible if thedeuterium vapor is introduced directly to the cryostat and cooled. Thus a large population of molecules isleft, under these circumstances, in the J l 1 state about 70 K higher in rotational energy than the J l 0ground state. The UCN scattering cross-section is about a factor of 30 higher from the para-deuteriumthan from ortho-deuterium, and UCN are almost always destroyed after a nuclear spin-flip scatter becauseof the enormous increase in energy available to the neutron in the final state.[24]

To mitigate this problem, our group built a prototype ortho-para converter based on the work ofBuyanov[46] which became the basis for the present design (after several iterations at Los Alamos) anddeveloped a rotational Raman spectrometry technique based on the work of Compaan and Wagoner[47]for determining the absolute para-/ortho-deuterium ratio to 0.1 percent. This Raman technique is also use-ful for identifying extremely small (0.1 percent) HD contaminations in our D2 as well. These technicaldevelopments, implemented in close collaboration with S. Lamoreaux at Los Alamos, have provided uswith the ability to control and measure the para- fraction precisely enough to reliably probe the physicsof UCN production. For example, with the para fraction reduced to below 2.0% we were able to observethe UCN lifetime in our SD2 decrease as we warmed our crystal, in extremely good agreement with ourpredictions based on loses due to upscatter from phonons present in the SD2, see Fig. 5.

Temperature (K)2qsolid D

4 5 6 7 8 9 10 11 12 13 14

(m

s)2

UC

N li

fetim

e in

D

0

5

10

15

20

25

30

35

40

Figure 5: UCN lifetime dependence on the temper-ature with a 2% paradeuterium in the SD2 crystal

These studies led, in June of this year, to highproton current runs in which we directed 100 µCof protons onto the target over about a second andproduced densities of 98 r 5 UCN/cm3 in a 3.6 literstainless steel bottle, with little evidence of heat-ing in our SD2[20]. The progress on our sourcehas been reported in over 13 talks and conferenceproceedings, as well as in two articles in refer-eed journals[48, 24]. An excellent reference forour progress to date can be found in the CAARI2000 conference proceedings[20]. At present, weare preparing three articles on different aspects ofour source development effort for publication. Wehave also initiated a collaborative study of VCN(neutrons with energies slightly greater than UCN)transmission through SD2 with our colleagues atPNPI which has already provided complimentaryinsight into the influence of crystal growth on UCNtransport, and should result in publications in thenext period.

Depolarization Studies: Over the past two years we have performed two sets of measurements of thedepolarization of UCN on material surfaces at ILL. This effort has been lead by Serebrov’s group fromPNPI, and has resulted in published upper limits for the depolarization/bounce of UCNs of (at the 95%confidence level) of 3 s 9 t 10 u 6 and 1 s 2 t 10 u 6 for Cu. Both of these lead to depolarization fractions below0.1% for our experimental geometry.[49] Recent, unpublished measurements suggest a more conservativeupper limit of about 0.15% for the depolarization should be adopted for now[50], however, we feel it islikely that future measurements of our diamond-coated substrates should permit us to push this upper limit

14

well below 0.1%.Our theoretical and experimental studies of depolarization were the subject of a senior thesis project

by U. Pesavento at Princeton. The theoretical estimates developed in this work should be submitted forpublication during the next academic year.

Detector development: We have designed, built, and tested a plastic scintillator beta detector as aprototype detector for the β-asymmetry measurement. The scintillator and light guides were designedin close cooperation with Bicron Corporation, which ultimately took the form of a 15.2cm square, 3mmthick piece of BC-404 plastic scintillator, edge-coupled to four acrylic light guides each of which consistsof four 3.8cm wide 0.6cm thick pieces. The scintillator and light guides were provided by Bicron. Eachlight guide extends 58cm away from the scintillator. Over this distance they are adiabatically bent so asto couple to a 51mm diameter Burle 8850 photo-multiplier tube. The edge-coupled configuration waschosen to maximize light yield and thus reduce the energy-threshold. We estimated a photon-yield of3040 photons per MeV deposited energy. The long light guides serve to transport the light out of thespectrometer magnet.

Using the Dynamitron at JPL we have performed a linearity test at the 3% level between 182keV and862keV. We find a linear offset of 20 v 5 w 3 v 0 keV, consistent with a similar detector used in PERKEOII[10]. We note that our linearity study is already comparable to the linearity studies performed in thePERKEO II experiment, and improvements of over an order of magnitude in the energy calibration arestraightforward and will be implemented in the next few months.

Other projects: During the last funded period, one of us completed work concerning the possi-ble existence of anomoulous electron-positron pairs in heavy ion collisions near the Coulomb Barrier(A. Young)[51]. We also successfully demonstrated that electronic spin relaxation times for Rb atomsin He vapor-filled cells below 2K exhibit extremely long relaxation times. Our data was consistentwith relaxation times which are longer than 35s, one of the longest electronic spin relaxation timesever observed.[52]. This work was a continuation of experiments begun at Princeton in collaborationwith W. Happer’s atomic physics group [53, 54, 55, 56]. Finally, one of us completed work concern-ing P non-invariance in heavy nuclei, utilizing neutron capture and epithermal neutron scattering (D.Smith).[57, 58, 59, 60, 61, 62]

15

SECTION D – REFERENCES CITED

Below is a selection of publications produced by members of our group during the last research period,organized by subject (we have omitted the references for over 12 talks and conference proceedings not inrefereed journals).

UCN Source Development

x “Ultra-Cold Neutron Upscattering in a Molecular Deuterium Crystal,” C.-Y. Liu, A. R. Young andS. K. Lamoreaux, Rapid Communications: Phys. Rev. B 62, R3581 (2000).

x “Performance of the prototype LANL solid deuterium ultra-cold neutron source,” R. E. Hill for theSD2 collaboration, with G. L. Greene, L. Marek, E. Pasyuk, A. Garcia, B. Fujikawa, S. Baessler,Nucl. Instr. and Meth. 440, 674 (2000).

UCN Depolarization

x “Depolarization of UCN Stored in Material Traps,” A. Serebrov, A. Vasiliev, M. Lasakov, Yu. Rud-nev, I. Krasnoshekova, P. Geltenbort, J. Butterworth, T. Bowles, C. Morris, S. Seestrom, D. Smith,A. R. Young, Nucl. Instr. and Meth. 440, 717 (2000).

Alkali Metal Vapor Optical Pumping in High Density He-filled Cells

x “Slow Spin Relaxation of Rb Atoms Confined in Glass Cells with Dense 4He Gas at 1.85 K,” A.Hatakeyama, K. Oe, S. Hara, J. Arai, T. Yabuzaki, and A. R. Young, Phys. Rev. Lett. 84, 1407(2000).

x “Light Narrowing of Rubidium Magnetic Resonance Lines in High-Pressure Optical Pumping Cells,”S. Appelt, A. Ben-Amar Baranga, A. R. Young, and W. Happer, Phys. Rev. A 59, 2078 (1999).

x “Alkali Polarization Imaging in High Pressure Optical Pumping Cells,” A. Ben-Amar Baranga, S.Appelt, C. J. Erickson, A. R. Young, and W. Happer, Phys. Rev. A 58, 2282 (1998).

x “Theory of Spin-Exchange Optical Pumping of 3He and 129Xe”, S. Appelt, A. Ben-Amar Baranga,C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, Phys. Rev. A, 58, 1412 (1998).

x “Polarization of 3He by spin exchange with optically pumped Rb and K vapors,” A. Ben-AmarBaranga, S. Appelt, M. V. Romalis, C. J. Erickson, A. R. Young, G. D. Cates and W. Happer, Phys.Rev. Lett. 80, 2801 (1998).

APEX

x “Positron-Electron Pairs Produced in Heavy-Ion Collisions,” I. Ahmad, Sam M. Austin, B. B. Black,R. R. Betts, F. P. Calaprice, K. C. Chan, A. Chishti, C. Conner,R. W. Dunford, J. D. Fox, S. J.Freedman, M. Freer, S. B. Gazes, A. L. Hallin, T. Happ, D. Henderson, N. I. Kaloskamis, E. Kashy,W. Kutschera, J. Last, C. J. Lister, M. Liu, M. R. Maier, D. J. Mercer, D. Mikolas, P. A. A. Perera,M. D. Rhein, D. E. Roa, J. P. Schiffer, T. A. Trainor, P. Wilt, J. S. Winfield, M. R. Wolanski, F. L. H.Wolfs, A. H. Wuosmaa, G. Xu, A. R. Young, and J. E. Yurkon (the APEX collaboration) Phys. Rev.C 60, 064601 (1999).

Symmetry Violations using Neutron Capture and Epithermal Neutron Beams

y “A High-Rate B-10-Loaded Liquid Scintillation Detector for Parity-Violation Studies in NeutronResonances”,Y. F. Yen, J. D. Bowman, R. D. Bolton, B. E. Crawford, P. P. J. Delheij, G. W. Hart,T. Haseyama, C. W. Frankle, M. Iinuma, J. N. Knudson, A. Masaike, G. E. Mitchell, S. I. Penttila,N. R. Roberson, S. J. Seestrom, E. Sharapov, H. M. Shimizu, D. A. Smith, S. L. Stephenson, J. J.Szymanksi, S. H. Yoo, V. W. Yuan (the TRIPLE collaboration) Nucl. Instr. and Meth. 447, 476(2000).

y “Measurement of the Parity Violating Asymmetry A(gamma) in n+p -¿ d+gamma,” W. M. Snow,A. Bazhenov, C. S. Blessinger, J. D. Bowman, T. E. Chupp, K. P. Coulter, S. J. Freedman, B. K.Fujikawa, T. R. Gentile, G. L. Greene, G. Hansen, G. E. Hogan, S. Ishimoto, G. L. Jones, J. N.Knudson, E. Kolomenski, S. K. Lamoreaux, M. B. Leuschner, A. Masaike, Y. Masuda, Y. Matsuda,G. L. Morgan, K. Morimoto, C. L. Morris, H. Nann, S. I. Penttila, A. Pirozhkov, V. R. Pomeroy, D.R. Rich, A. Serebrov, E. I. Sharapov, D. A. Smith, T. B. Smith, R. C. Welsh, F. E. Wietfeld, W. S.Wilburn, V. W. Yuan, J. Zerger (the NPDGAMMA collaboration), Nucl. Instr. and Meth. 440, 729(2000).

y “Neutron resonance spectroscopy of Rh-103 from 30 eV to 2 keV”,D. A. Smith, J.D. Bowman, B.E.Crawford, C.A. Grossmann, T. Haseyama, A. Masaike, Y. Matsuda, G.E. Mitchell, S.I. Penttila,N.R. Roberson, S.J. Seestrom, E.I. Sharapov, S.L. Stephenson, V. Yuan, Phys. Rev. C 60, 045502/1(1999).

y “Parity violation in neutron resonances of Rh-103 ”, D. A. Smith, J.D. Bowman, B.E. Crawford,C.A. Grossmann, T. Haseyama, A. Masaike, Y. Matsuda, G.E. Mitchell, S.I. Penttila, N.R. Roberson,S.J. Seestrom, E.I. Sharapov, S.L. Stephenson, V. Yuan, Phys. Rev. C 60, 045503/1 (1999).

y “Neutron resonance spectroscopy of Sn-117 from 1ev to 1.5keV”, D. A. Smith, J.D. Bowman, B.E.Crawford, C.A. Grossmann, T. Haseyama, M.B. Johnson, A. Masaike, Y. Matsuda, G.E. Mitchell,V.A. Nazarenko, S.I. Penttila, N.R. Roberson, S.J. Seestrom, E.I. Sharapov, L.M. Smotritsky, S.L.Stephenson, V. Yuan, Phys. Rev. C 59, 2836 (1999).

y “Parity nonconservation in neutron capture on Cd-113”, S.J. Seestrom, J.D. Bowman, B.E. Craw-ford, P.P.J Delheij, C.M. Frankle, C.R. Gould, D.G. Haase, M. Iinuma, J.N. Knudson, P.E. Koehler,L.Y. Lowie, A. Masaike, Y. Masuda, Y. Matsuda, G.E. Mitchell, S.I. Penttila, Y.P. Popov, H. Postma,N.R. Roberson, E.I. Sharapov, H.M. Shimizu, D.A. Smith, S.L. Stephenson, Y.F. Yen, V.W. Yuan,Phys. Rev. C 58, 2977 (1998).

The UCN beta-asymmetry collaboration: A. Alduschenkov1 , J. M. Anaya2, K. Asahi3, T. J.Bowles2, T. Brun2, B. W. Filippone4, M. Fowler2, P. Geltenbort5, R. E. Hill2, A. Hime2, M. Hino6,S. Hoedl7, G. Hogan2, T. Ito4, C. Jones4, T. Kawai6, A. Kharitonov1, T. Kitagaki8, S. Lamoreaux2,M. Lassakov1, C.-Y. Liu7, M. Makela9, R. McKeown4, C. L. Morris2, R. Mortensen2 , Y. Rudnev1, A.Saunders2, S. J. Seestrom2, A. Serebrov1, D. A. Smith7, K. Soyama10, W. Teasdale2, M. Utsuro6, A.Vasilev1, R. B. Vogelaar9, A. R. Young11, J. Yuan4, P. Walstrom2

1 St. Petersburg Nuclear Physics Institute2 Los Alamos National Laboratory

3 Tokyo Institute of Technology4 California Institute of Technology

5 Institut Laue-langevin6 Kyoto University

7 Princeton University

2

8 Tohoku University9 Virginia Polytechnical University

10 JIRI11 North Carolina State University

References

[1] I. Towner and J. Hardy, Proceedings of the Wein 98 Conference; Los Alamos preprint server articleno: 9809087 (1998).

[2] P. R. Huffman et al z , Nature 403, 62 (2000).

[3] B. K. Fujikawa et al z , Phys. Lett. B 449, 6 (1999).

[4] G. Savard et al z , Phys. Rev. Lett. 74, 1521 (1995).

[5] G. C. Ball et al z , unpublished preprint (2000).

[6] H. Abele, Nucl. Instr. and Meth. A 440, 499 (2000).

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[8] B. G. Erozolimskii, Phys. Lett. B236, 33 (1991).

[9] P. Liaud et al z , Phys. Lett. B349, 427 (1995).

[10] H. Abele et al z , Phys. Lett. 407, 212 (1997).

[11] B. G. Erozolimskii et al z , Phys. Lett. B 412, 240 (1997).

[12] J. Reich et al z , Nucl. Instr. and Meth. A 440, 535 (2000).

[13] P. Langacker and S. Sankar, Phys. Rev. D 40, 1569 (1989).

[14] M. Ramsey-Musolf, Phys. Rev. D 62a, 056009 (2000).

[15] J. Deutsch, Proceedings of the Wein 98 Conference; Los Alamos preprint server article no: 9901098(1998), and J. Deutsch and P. Quin, Precision Tests of the Standard Electroweak Model, P. Langacker,ed. (World Scientific:Singapore, 1993).

[16] F. Calaprice et al z , Phys. Rev. Lett. 35, 1566 (1975).

[17] P. Herczeg, Precision Tests of the Standard Electroweak Model (World Scientific, Singapore 1993).

[18] C. Caso et al z , Review of Particle Physics (Particle Data Group), Eur. Phys. J. C 3, 1 (1998).

[19] M. Anaya et al z ,“A Technical Review Report for an Accurate Measurement of the Neutron Spin-Electron Angular Correlation in Polarized Neutron Beta Decay with Ultra-Cold Neutrons,” (2000).

[20] K. Kirch et al z , proc. of the 2000 CAARI conference.

[21] A. Steyerl et al z , Phys. Lett. A 116, 347 (1986).

[22] G. L. Jones, Ph.D. thesis, Princeton University (1995).

[23] R. Golub and K. Boning, Z. Phys. B 51, 95 (1983).

[24] C.-Y. Liu, A. R. Young, and S. K. Lamoreaux, Rapid Communications: Phys. Rev. B 62, R3581(2000).

[25] P. W. Stephens and C. F. Majkrzak, Phys. Rev. B 33, 1 (1986).

[26] A. Abragam, The Principles of Nuclear Magnetism, (Oxford Press: London), 35 (1961).

[27] M. V. Romalis, Ph.D. thesis, Princeton University (1997).

3

[28] C. E. Hayes et al { , J. of Mag. Res. 63, 622 (1985).

[29] J. Link, ‘The Design of Resonator Probes with Homogeneous Radiofrequency Fields,” in NMR BasicPrinciples and Progress, vol. 26 (Springer-Verlag, Berlin 1992), p. 1.

[30] R. Gamblin and T. Carver, Phys. Rev 138, A946 (1965).

[31] T. A. Friedmann et al { , Appl. Phys. Lett. 71, 3820 (1997).

[32] Our letter of intent can be viewed at ftp://wis.lanl.gov/ UCNA prop v13.

[33] J. L. Mortara et al | , Phys. Rev. Lett. 70, 394 (1993).

[34] R. Brun et al | , CERN Report DD/EE/84-1, Geneva, 1986.

[35] W. R. Nelson, H. Hirayama, and D. W. O. Rogers, Report SLAC-265, Stanford Linear AcceleratorCenter, Stanford, California, 1985.

[36] I. Kawrakow, Medical Physics 27, 485 (2000).

[37] J. A. Halbleib et al | , Technical Report SAND91-1634, Sandia National Laboratories, 1992.

[38] F. Salvat et al | , Technical Report 799, Informes Tecnicos Ciemat, Madrid, 1996.

[39] P. Gerard et al | , Scanning 17, 377 (1995), G. Massoumi, W. N. Lennard, and P. J. Schultz, Phys. Rev.B 47, 11007 (1993).

[40] S. Hoedl et al | , to be presented at the APS, Division of Nuclear Physics Meeting, October (2000).

[41] R. Mayol and F. Salvat, At. Data and Nucl. Data Tables 65, 156 (1997).

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[43] B. G. Yerozlimsky, Nucl. Instr. and Meth. A 440, 491 (2000).

[44] J. C. Reich, PhD thesis, Rupertus Carolina University of Heidelberg, (1999).

[45] A. Hallin et al | , Phys. Rev. Lett. 52, 337 (1984).

[46] R. A. Buyanov, Kinetika i Kataliz 1, 306 (1960).

[47] A. Compaan and A. Wagoner, Am. J. Phys. 62, 639 (1994).

[48] R. Hill et al | , Nucl. Instr. and Meth. A 440, 674 (2000).

[49] A. P. Serebrov et al | , Nucl. Instr. and Meth. A 440, 717 (2000).

[50] A. P. Serebrov, unpublished, (2000).

[51] I. Ahmad et al | , Phys. Rev. C 60, 065601 (1999).

[52] A. Hatakeyama et al | , Phys. Rev. Lett 84, 1407 (2000).

[53] A. Ben-Amar Baranga et al | , Phys. Rev. Lett80, 2801 (1998).

[54] S. Appelt et al | , Phys. Rev. A 58, 1412 (1998).

[55] A. Ben-Amar Baranga et al | , Phys. Rev. A 58, 2282 (1998).

[56] S. Appelt et al | , Phys. Rev. A 59, 2078 (1999).

[57] Y. F. Yen et al | , Nucl. Instr. and Meth. 447, 476 (2000).

[58] W. M. Snow et al | , Nucl. Instr. and Meth. 440, 729 (2000).

[59] D. A. Smith et al | , Phys. Rev. C 60, 045502/1 (1999).

19

[60] D. A. Smith et al } , Phys. Rev. C 60, 045503/1 (1999).

[61] D. A. Smith et al } , Phys. Rev. C 59, 2836 (1999).

[62] S. J. Seestrom et al } , Phys. Rev. C 58, 2977 (1998).

5

Albert R. YoungBrief Biography and Representative Publications

September 2000Personal

Born January 9, 1960, Berkeley, CaliforniaEducation

University of Washington (in Seattle) Physics B.S., 1982Harvard Univeristy Physics Ph.D., 1990California Institute of Technology Nuclear Physics 1990 - 1992Princeton University Nuclear Physics 1992 - 2000

EmploymentAssistant Professor of Physics, NCState University 2000-currentAssistant Professor of Physics, Princeton University 1996-2000Lecturer, Princeton University 1994-1996Research Associate, Princeton University 1992-1994Junior Research Fellow, California Institute of Technology 1990-1992Teaching Fellow, Harvard University 1986-1987Research Assistant, Harvard University 1983-1990Honors Tutor, University of Washington 1979-1980

Academic HonorsGraduated Univ. of Wash. with college and deparmental honors (1982)

Closely Related Publications

Ultra-Cold Neutron Upscattering in a Molecular Deuterium Crystal, C.-Y. Liu, A. R. Young andS. K. Lamoreaux, Rapid Communications: Phys. Rev. B 62, R3581 (2000).

Depolarization of UCN Stored in Material Traps, A. Serebrov, A. Vasiliev, M. Lasakov, Yu.Rudnev, I. Krasnoshekova, P. Geltenbort, J. Butterworth, T. Bowles, C. Morris, S. Seestrom, D.Smith, A. R. Young, Nucl. Instr. and Meth. 440, 717 (2000).

Performance of the Prototype LANL Solid Deuterium Ultra-Cold Neutron Source R. E. Hill forthe SD2 collaboration, with G. L. Greene, L. Marek, E. Pasyuk, A. Garcia, B. Fujikawa, S.Baessler, Nucl. Instr. and Meth. 440, 674 (2000)

Slow Spin Relaxation of Rb Atoms Confined in Glass Cells with Dense 4He Gas at 1.85 K, A.Hatakeyama, K. Oe, S. Hara, J. Arai, T. Yabuzaki, and A. R. Young, Phys. Rev. Lett. 84, 1407(2000).Experimental Search for the Violation of Fundamental Symmetries in 182W, A. R. Young, J.Carter, A. Griffiths, and F. Boehm, Hyp. Int 75, 199 (1992).

Significant Publications

Theory of Spin-Exchange Optical Pumping of 3He and 129Xe, S. Appelt, A. Ben-Amar Baranga,C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, Phys. Rev. A, 58, 1412 (1998).

1

Polarization of 3He by spin exchange with optically pumped Rb and K vapors, A. Ben-AmarBaranga, S. Appelt, M. V. Romalis, C. J. Erickson, A. R. Young, G. D. Cates and W. Happer,Phys. Rev. Lett. 80, 2801 (1998).

Three-dimensional Imaging of Spin Polarization of Alkali-metal Vapor in Optical Pumping Cells,A. R. Young, S. Appelt, A. Ben-Amar Baranga, C. Erickson, and W. Happer, App. Phys. Lett.70, (1997).

Search for Monoenergetic Positron Emission from Heavy-ion Collisions at Coulomb-barrier En-ergies, Phys. Rev. Lett 78, 618 (1997).

Dielectronic Recombination for C3 ~ in a Known External Field D. W. Savin, L. D. Gardner, D.B. Reisenfeld, A. R. Young, and J. L. Kohl, Phys. Rev. A 53, 280 (1996).

Synergistic Activities: I have initiated an outreach program, “Learn-by-Teaching” at Princeton,which has been incorporated into the curriculum of the Princeton Physics department.

Collaborations: For a complete list of the members of the β-asymmetry collaboration (collab-orators on this proposal) and the APEX collaboration, please see SECTION D–REFERENCESCITED.

Graduate and Post-Doctoral Advisors: Thesis advisor: J. Kohl, Harvard-Smithsonian Centerfor Astrophysics, Post-Graduate Advisors: F. Boehm, Caltech, F. Calaprice, Princeton, G. Cates,Princeton.

Graduate Students: (2) graduate students: C.-Y. Liu (current) and S. Hoedl (current). (1) post-graduate scholar: D. Smith.

2

Charles W. MayoBrief Biography and Representative Publications

September 2000Education

NC State University Nuclear Engineering B.S., 1971NC State University Nuclear Engineering Ph.D., 1990

Employment1999-2000 Professor of Nuclear Engineering 1999-currentand Nuclear Reactor Program Director, NC State UniversityAssociate Professor of Nuclear Engineering 1991-2000and Nuclear Reactor Program Director, NC State UniversityStaff Scientist, Division Manager, Senior Scientist 1979-1991Scientific Applications International CorporationGroup Supervisor Nuclear Physics Section 1979-1991Babcock & Wilcox Lynchburg Research CenterSenior Engineer 1974-1978Babcock & Wilcox Nuclear Power Generation Division

Closely Related Publications

Monte Carol Assisted Quality Assurance for In Vivo and In Situ Elemental Analysis Using Nu-clear Analytical Techniques, R.P. Gardner, S.H. Lee, C.W. Mayo, E.S. El Sayyed, and A. Sood,Transactions of the American Nuclear Society, Vol. 79, pp. 20-21, (1998).

MCNP Criticality Benchmark Calculations for the NCSU PULSTAR reactor, C.W. Mayo, K.Verghese, Y.G. Huo, Proceedings of the American Nuclear Society Topical Meeting - Advancesin Nuclear Fuel Management II, Electric Power Research Institute Report TR-107728, (1997).

Auto Regressive Moving Average Inverse Dynamics for Rhodium Self Powered Neutron Detector,C.W. Mayo, L. Yan, Nuclear Science and Engineering V. 124, No. 2, (1996).

Two-Dimensional, Multigroup Model of the NCSU PULSTAR reactor, E. Giavedoni, P.B. Perez,C.W. Mayo, Transactions of the American Nuclear Society, Vol. 173, (1995).

Determination of the PULSTAR Research Reactor Neutron Energy Spectrum, S.V. Pullela, P.B.Perez, C.W. Mayo, D.J. Dudziak, Transactions of the American Nuclear Society, V.71, p.146,(1994).

Enhancing the NCSU PULSTAR Reactor Excess Reactivity Utilizing Beryllium, P.B. Perez, C.W.Mayo, Transactions of the American Nuclear Society, V.70, p.129, (1994).Significant Publications

A feasibility study of a coincidence counting approach for PGNAA applications, Gardner, R.P.;Mayo, C.W., El-Sayyed, E.S;, Metwally, W.A.; Zheng, Y.; Poezart, M., Applied Radiation andIsotopes; 53 (4-5), (2000).

NaI Detector Nonlinearity for PGNAA Applications, R.P. Gardner and C.W. Mayo, Applied Ra-diation and Isotopes, Vol. 51, pp. 189-195, (1999).

1

Enhancing the NCSU PULSTAR Reactor Excess Reactivity Utilizing Beryllium, P.B. Perez,C.W. Mayo, Transactions of the American Nuclear Society, V.70, p.129, (1994).

Collaborations: For a complete list of the members of the β-asymmetry collaboration (collabo-rators on this proposal).

2

�� Q��K ¢¡¤£¢¥§¦o¦�¡� ¨¡�£ª©«�¤�§¬¥§®� °¯±��²¤³�¤¥§¥´ µ³��²¤¶Q©«¡� ¢�·¹¸�®´ ¢¡¤¬p³p��®»º¼�®§�p¥»½��³¾¤¥´ µ¦�³p�¿��À�Á��Â�� K·ÄÃ Å«Ã±©Æ��§¬¥�®§ °¯±��²¤³�¤¥§¥§ µ³��²¤¶¨ÇQÈ�É�É�¶�½��¤³¾¤¥§ ¢¦o³�p¿Ê¡�£°ËÌ¬¬p³��¡¤³¦Í�Ã ºÎÃÏ�K·�¿¤¦�³��¦�¶ÄÇ�È�ÉKÇQ¶�½��³¾¤¥§ µ¦�³p�¿¹¡�£¨ËÌ¬¬³p��¡�³p¦ÐÊÃ ºÑÃ ¯ÒÃQÓ¢Í®��·¤ÔÕ¶ÄÇQÈ�Ö�È¤¶¤×Ø·�¥Ò½��¤³¾¤¥§ ¢¦�³p�¿¹¡�£¨ÍÙ³Ú�§·¤³p²¤®´�ÐÊÃ ºÑÃ ¯ÒÃQÓ¢�Û·�¿¤¦�³��¦�Ô¢¶ÄÇQÈ¤Ö�È�¶¤×Ñ·�¥»½��¤³¾¤¥§ ¢¦o³�¿¹¡�£ÄÍ³p�´·�³²¤®§��ÜÞÝØ�ßÂ�à�ÜÞ��Ç�È�É�É�á�ÇQÈ�â�ã ��¦�¦ä³¦o�®§�¤��K µ¡�£¢¥�¦�¦ä¡¤ ¨¡�£�©Æ�¤�§¬¥�®§ °¯å��²¤³��¥§¥� ¢³��²¤¶�½��³¾¤¥§ ¢¦o³�¿¹¡�£¨ËÌ¬¬³p��¡�³p¦Ç�È�â�ã�á�ÇQÈ�â�â ��¦�¦�¡��§³p®´�p¥Ò�K ¢¡¤£¢¥§¦o¦�¡� Ä¡�£�©«��§¬p¥�®§ ¨¯Ø��²æ³Ú�¤¥§¥§ µ³��²¤¶Ç�È�â�â�á�ÇQÈ�ç�è �K ¢¡�£¢¥�¦�¦�¡¤ °¡�£�©Æ��§¬p¥§®´ ¨¯å��²¤³��¥§¥� ¢³��²¤¶Ç�È�çÄÇQá�ÇQÈ�ç�é ê´ë�¥§¾¤¡�¬¾¤³��²¤ìÒ��¦�¦�³¦o�®§�¤�íÅ�¥§®§�î¡�£¨¯Ø��²¤³��¥�¥§ µ³��²¤¶Ç�È�ç�è�á�ÇQÈ�ç�È �K ¢¡�£¢¥�¦�¦�¡¤ °¡�£�©«��§¬p¥§®§ °¯å��²¤³��¥§¥� Õ³p��²¤¶Q©Æ¡� µ�·î¸�®§ µ¡�¬p³��®»º¼�®��¥»½��¤³¾¤¥§ ¢¦�³p�¿Å�³ Õ¥§��¡¤ Õ¶Q©«��¬¥§®� °ë�¥´®��§�¡¤ °�Û ¢¡�²¤ ¢®§ïð¶Ç�È�ç�È�áÌé�ã�ã�ã �K ¢¡�£¢¥�¦�¦ä¡¤ µ¶�ÍÙ¥§�§·�®��³��®§¬í¯å��²¤³��¥´¥� ¢³��²¤¶¤×Ø·�¥Ò½��¤³¾¤¥§ ¢¦�³p�¿Ê¡�£°×±¥´ñ¤®§¦ò®��¦o�p³�Å�³ ¢¥§��¡¤ ¢¶�©«��¬¥§®� ¨¯Ø��²¤³��¥§¥� ¢³��²�×Ñ¥§®��§·�³p��²¹óØ®§ô�¡� µ®��Ú¡� ¢¿��¹õæ��Á��K ¢¡�£¢¥�¦�¦ä¡¤ ¨ö ¥§·� µ³��²Ê·�®§¦ò·¤®§�î�§¡��¤¦�³�¤¥§ µ®§ô�¬p¥Ò¥´ñ�÷¤¥§ µ³¥´��¥»³�î�¤¥§¦o³²¤��³��²Ê®§��î�§®� ¢ ¢¿¤³��²Ê¡��¥§ñ�÷�¥� ¢³ïð¥§��¦³��¾¤¡�¬¾¤³��²Ê¦�¥§¾¤¥§ ¢¥» ¢®��³®��³p¡��îô�®��§ø¤²¤ Õ¡��¶�£¢®§¦o�ª�³ïð³��²¤¶�®§��îïð��¬p�³÷�®� ¢®§ïð¥§�¥� °��®��®»®��§ù��³p¦�³p�³p¡��î¦ä¿¤¦��¥§ïð¦úÃû�¥»·�®§¦Î��¡��p ¢³ô¤��¥��îô�¡¤�p·î³�Ê�·¤¥»²¤¥§��¥§ ¢®��³p¡��î¡�£Äô�®§¦o³�»�¤��§¬¥�®� °��®��p®»®§�¤�î�·¤¥»��¥´¾¤¥§¬¡¤÷�ïð¥§��¡�£¨�¤¥§ü³��¦o� ¢��ïð¥§��¦Î®§��î��¥§ü�¥§ñ�÷�¥Q ¢³ïð¥§��p®�¬í�p¥§�´·��¤³ù��¤¥§¦ýÃ�ë�¥�¦�¥§®� Õ�§·¹³��³p�p³®§�p¥§�î��¤ ¢³��²Ê�·¤¥Ò¬p®´¦��°Ç�ãÊ¿¤¥´®§ µ¦Î��¥� ·�³¦Î¦o��÷�¥� ¢¾¤³¦�³¡��Ê³p��¬��¤¥»��¥�¦ä³p²¤�î®§��¹�´¡��¦o� ¢�¤�§�p³¡��î¡¤£¨®Ò�§¡�¬�Ê��¥§�¤�Ú ¢¡��¹¦ä¡��¤ ¢�§¥§¶��¥§¦o³²¤�î®§��Ê�´¡¤��¦��p ¢��p³p¡��¡�£¨®»��¤³pù��¤¥»�§¡��¾¤¥§ ¢²¤³��²Ê��¥´��p ¢¡��î²¤��³�¤¥´¶��§¡¤¬��áÌ��¥´�� ¢¡¤�î÷� ¢¡�ïð÷��²¤®§ï�ïð®Ò®´�§�³p¾¤®´�³p¡¤�î®´�¤®§¬¿¤¦�³¦�¶¤®§��¥§¦�³²¤�î®§��Ê�§¡��¦o� µ��§�p³Ú¡��Ê¡�£°®þ ¢¥�®§�§�p¡� ¨ô¤®´¦�¥§�Ê¦�¬¡�üÿ÷�¡�¦o³�p ¢¡��îô�¥�®§ï £¢®§�´³p¬p³p�¿õæ��Á��ÝØÀ��þ��Á��Â«�«õ �� Ç�Ã ÐÊÃQö ÃQöÞ¥�·� µ³p��²¹®§�� ÃQ½��¬��¶¤êþ×Ñ·�¥»½��¤³¾¤¥§ ¢¦o³�¿¹¡�£¨×±¥§ñ�®§¦Î¸�¡¤¬�þ©«¥§�¤�Ú µ¡��îºÛ¡��¤ ¢�§¥��K ¢¡��§¥�¥´��³��²¤¦ò¡¤£¨ËÌ��¥§ ¢��®��³p¡¤��®§¬�º¼¥§ïð³Ú��®§ °¡��î��¾¤®§��¥§�î�Û�¤¬¦�¥§�þ©�¥§��p ¢¡��îºK¡¤�� ¢��¥§¦��´�Û·�¿¤¦�³�§¦Ñ¡�£��p®´��¾¤®´��§¥§�î�Û��¬¦o¥§�þ©«¥§�¤�Ú µ¡¤�îºK¡��¤ ¢�§¥§¦o¶��K�ò©Æº ËµËµ¶�Å��ô��®§¶�ë��¦�¦�³p®§¶��ä�¤��¥ ÇQè�á�ÇQÉ�¶ÄÇQÈ�È�Ö¨Ãé¨Ã ÐÊÃQö ÃQöÞ¥�·� µ³p��²¤¶��äá �ÆÃ��¹³ïð¶�®§��!�ÆÃ�½��¬p��¶¤ê ©Æ¥§�¤� µ¡�� "K¡��§��¦o³Ú��²¹ºK¿¤¦��¥§ï £¢¡� ¨�·¤¥þ×Ñ¥§ñ¤®§¦ò¸�¡¤¬�©Æ¥§��p ¢¡¤�îºK¡�� µ�§¥§¶¤ê ©Æ��§¬ÕÃ ËÌ��¦�� ÃQ®§��¹Í�¥��p·¨Ã ³�Ê�K·�¿¤¦úÃ�ë�¥´¦úÃQ�$#�Ö�#�¶¨Ç�#�âÊÓ ÇQÈ�È�è¤Ô Ã#¨Ã ÐÊÃQö ÃQöÞ¥�·� µ³��²Ê®§��%�ÆÃ�© ÃQ�K¡�ø¤¡��³p¬¡�¾¤¦�ø¤³¶îê»ºÛ�¡¤ ¢®§²¤¥»¡�£¨½�¬p�p ¢®§��¡�¬p�þ©Æ¥��p ¢¡��¦Ñ®§��î®Ò×Øë�Ë &��K��¬¦�¥»áµáK��Í�®§ µ µ³®§²¤¥»Í®§�¤¥»³�¹û�¥§®§¾¤¥§��¶ ìÒ×± ¢®§��¦úÃ ��ï�Ã ©«��§¬ÕÃ�ºÛ¡��ÃQâ�#�¶¨Ç Ö�#îÓäÇQÈ�È�Ö�ÔäÃè¨Ã Ð¹Ã�ö ÃQöÞ¥�·� µ³��²¹®´��!�ÆÃQ½��¬��¶¤ê»��÷�÷¤¬³��®§�p³¡��¦Î¡�£°¸�¡¤¬��á ©«¥´�� ¢¡��î�¼ ¢¡�ïð÷��'&�®§ï ïð®»��§�p³¾¤®§�³¡��®§¬¿¤¦�³¦Ñ®§�ª�·�¥»½��¤³¾¤¥§ ¢¦o³�¿¹¡�£¨×Ø¥§ñ¤®´¦Îë�¥�®§��¡� ¢¶ ìÒ��÷�÷�¬�ÃQëß®§�ÄÃ�®§�¤�îËÌ¦�¡��¡�÷�¥§¶�è�ç�¶KÇ�#�è�#ÊÓäÇ�È�È�â¤Ô ÃÖ ÐÊÃ�ö ÃQöÞ¥�·� µ³��²¤¶�Í®´ µ�³p�þ©«³¦�¥��¶¤®§��îÅ�¡��¤®)(+*��¥�¬¬¿¤¶�ê§×Ø³ïð¥§áÌ¡�£Õá "Û¬³²¤·��íÍ¥§®§¦o�� ¢¥´ïî¥´��¦Î®��®¸�¡�¬�þ©«¥§�¤� ¢¡��îº¼¡�� µ�§¥»½�¦o³��²Ê®»ë�¥§®§��¡� °�¼¡�ü�¥´ ¨�K�¤¬¦o¥§¶ ì»®��§�§¥�÷��¥´�¹£¢¡¤ °÷� µ¥´¦�¥��®��³p¡��î®��í�·�¥Ò��ï�Ã©Æ��§¬ÕÃ�ºÛ¡��ÃQËÌ��¥§ ¢��®��³p¡��¤®§¬ªÍ¥§¥��p³��²¤¶Q©Æ¡�¾¤¥´ïðô�¥´ ßÇQé�áoÇ�É�¶�é�ã�ã�ã¨Ãõæ��Á�� ¹��¹õ ��, ��Ç�Ã ½�¬� µ®»¸�¡�¬��©Æ¥§��p ¢¡��îºÛ¡¤�� ¢��¥Òë�¥§¦o®´ µ�´·¹®§��p·�¥þ½��³p¾¤¥§ ¢¦o³�¿Ê¡�£Ä×Ø¥§ñ�®§¦K©Æ��§¬p¥´®§ ¨ëß¥§®§��¡� µ¶¤×Ø¥§ñ�®�¦�á��×Ñ�Û¶�-�È�ã¤¶ ã�ã�ã�¶ÄÇ.��Ç.�È�çîáÄç��/#¨Ç��ã�ãKÃé¨Ã ¯Øñ�÷�¥´ µ³��ïð¥§��p®�¬íºÛ��¤��¿Ê¡�£°½�¬p�p Õ®Ò¸�¡¤¬�þ©Æ¥§�¤� ¢¡¤�îó±¡��§®�¬p³�0�®§�³¡¤�î®§��îº¼��ô�áÌô�®§ ¢ ¢³¥� ¨�K¥§�¤¥§�p Õ®§�p³p¡��¤¶Å$(�¯Øá ©«¯Ø¯±ë�¶�-ÄÇQé�#�¶ É�Ö�é�¶�â��Ç��pÈ�çîáKÉ��#ÄÇ��ãÄÇ

SUMMARYPROPOSAL BUDGET

FundsRequested By

proposer

Fundsgranted by NSF

(if different)

Date Checked Date Of Rate Sheet Initials - ORG

NSF FundedPerson-mos.

FOR NSF USE ONLYORGANIZATION PROPOSAL NO. DURATION (months)

Proposed Granted

PRINCIPAL INVESTIGATOR / PROJECT DIRECTOR AWARD NO.

A. SENIOR PERSONNEL: PI/PD, Co-PI’s, Faculty and Other Senior Associates (List each separately with title, A.7. show number in brackets) CAL ACAD SUMR

$ $1.

2.

3.

4.

5.

6. ( ) OTHERS (LIST INDIVIDUALLY ON BUDGET JUSTIFICATION PAGE)

7. ( ) TOTAL SENIOR PERSONNEL (1 - 6)

B. OTHER PERSONNEL (SHOW NUMBERS IN BRACKETS)

1. ( ) POST DOCTORAL ASSOCIATES

2. ( ) OTHER PROFESSIONALS (TECHNICIAN, PROGRAMMER, ETC.)

3. ( ) GRADUATE STUDENTS

4. ( ) UNDERGRADUATE STUDENTS

5. ( ) SECRETARIAL - CLERICAL (IF CHARGED DIRECTLY)

6. ( ) OTHER

TOTAL SALARIES AND WAGES (A + B)

C. FRINGE BENEFITS (IF CHARGED AS DIRECT COSTS)

TOTAL SALARIES, WAGES AND FRINGE BENEFITS (A + B + C)

D. EQUIPMENT (LIST ITEM AND DOLLAR AMOUNT FOR EACH ITEM EXCEEDING $5,000.)

TOTAL EQUIPMENT

E. TRAVEL 1. DOMESTIC (INCL. CANADA, MEXICO AND U.S. POSSESSIONS)

2. FOREIGN

F. PARTICIPANT SUPPORT COSTS

1. STIPENDS $

2. TRAVEL

3. SUBSISTENCE

4. OTHER

TOTAL NUMBER OF PARTICIPANTS ( ) TOTAL PARTICIPANT COSTS

G. OTHER DIRECT COSTS

1. MATERIALS AND SUPPLIES

2. PUBLICATION COSTS/DOCUMENTATION/DISSEMINATION

3. CONSULTANT SERVICES

4. COMPUTER SERVICES

5. SUBAWARDS

6. OTHER

TOTAL OTHER DIRECT COSTS

H. TOTAL DIRECT COSTS (A THROUGH G)

I. INDIRECT COSTS (F&A)(SPECIFY RATE AND BASE)

TOTAL INDIRECT COSTS (F&A)

J. TOTAL DIRECT AND INDIRECT COSTS (H + I)

K. RESIDUAL FUNDS (IF FOR FURTHER SUPPORT OF CURRENT PROJECTS SEE GPG II.D.7.j.)

L. AMOUNT OF THIS REQUEST (J) OR (J MINUS K) $ $

M. COST SHARING PROPOSED LEVEL $ AGREED LEVEL IF DIFFERENT $

PI / PD TYPED NAME & SIGNATURE* DATE FOR NSF USE ONLYINDIRECT COST RATE VERIFICATION

ORG. REP. TYPED NAME & SIGNATURE* DATE

NSF Form 1030 (10/99) Supersedes all previous editions *SIGNATURES REQUIRED ONLY FOR REVISED BUDGET (GPG III.B)

1YEAR

1


Albert

Albert

Albert

R

R

R

Young

Young

Young - none 0.00 0.00 0.00 0Charles W Mayo - none 0.00 0.00 0.00 0Bernard W Wehring - none 0.00 0.00 0.00 0

0 0.00 0.00 0.00 03 0.00 0.00 0.00 0

2 18.00 0.00 0.00 52,5000 0.00 0.00 0.00 02 34,0000 00 00 0

86,5008,966

95,466

18,900$LeCroy Fast Digital Scope

18,90017,2005,000

00000 0

3,4001,100

000

3,000 7,500

144,066

57,418Benefits (Rate: 47.0000, Base: 8966) (Cont. on Comments Page)

201,4840

201,48428,200

SUMMARY PROPOSAL BUDGET COMMENTS - Year 1

** I- Indirect CostsPublications (Rate: 47.0000, Base 1100)Salaries (Rate: 47.0000, Base 86500)Supplies (Rate: 47.0000, Base 3400)Travel (Rate: 47.0000, Base 22200)


FundsRequested By

proposer

Fundsgranted by NSF

(if different)




Proposed Granted



$ $1.

2.

3.

4.

5.









6. ( ) OTHER





TOTAL EQUIPMENT


2. FOREIGN


1. STIPENDS $

2. TRAVEL

3. SUBSISTENCE

4. OTHER







5. SUBAWARDS

6. OTHER












2YEAR

2


Albert

Albert

Albert

R

R

R

Young

Young


0 0.00 0.00 0.00 03 0.00 0.00 0.00 0

2 18.00 0.00 0.00 52,5000 0.00 0.00 0.00 02 34,0000 00 00 0

86,5008,966

95,466

6,599$Ar+ laser2,700digital filter6,250frequency synthesizer5,800three axis flux-gate magnetometer

21,34917,2005,000

00000 0

3,4001,100

000

3,000 7,500

146,515


203,9330

203,93328,200


** I- Indirect CostsPublication (Rate: 47.0000, Base 1100)Salaries (Rate: 47.0000, Base 86500)Supplies (Rate: 47.0000, Base 3400)Travel (Rate: 47.0000, Base 22200)


FundsRequested By

proposer

Fundsgranted by NSF

(if different)




Proposed Granted



$ $1.

2.

3.

4.

5.









6. ( ) OTHER





TOTAL EQUIPMENT


2. FOREIGN


1. STIPENDS $

2. TRAVEL

3. SUBSISTENCE

4. OTHER







5. SUBAWARDS

6. OTHER












3YEAR

3


Albert

Albert

Albert

R

R

R

Young

Young


0 0.00 0.00 0.00 03 0.00 0.00 0.00 0

2 18.00 0.00 0.00 52,5000 0.00 0.00 0.00 02 34,0000 00 00 0

86,5008,966

95,466

3,540$100kV power supply7,800Dry pumping station9,500H+ ion source

20,84017,2005,000

00000 0

3,4001,100

000

3,000 7,500

146,006


203,4240

203,42428,200


** I- Indirect CostsPublications (Rate: 47.0000, Base 1100)Salaries (Rate: 47.0000, Base 86500)Supplies (Rate: 47.0000, Base 3400)Travel (Rate: 47.0000, Base 22200)


FundsRequested By

proposer

Fundsgranted by NSF

(if different)




Proposed Granted



$ $1.

2.

3.

4.

5.









6. ( ) OTHER





TOTAL EQUIPMENT


2. FOREIGN


1. STIPENDS $

2. TRAVEL

3. SUBSISTENCE

4. OTHER







5. SUBAWARDS

6. OTHER












Cumulative

C


Albert

Albert

Albert

R

R

R

Young

Young


0.00 0.00 0.00 03 0.00 0.00 0.00 0

6 54.00 0.00 0.00 157,5000 0.00 0.00 0.00 06 102,0000 00 00 0

259,50026,898

286,398

61,089$

61,08951,60015,000

00000 0

10,2003,300

000

9,000 22,500 436,587

172,254

608,8410

608,84184,600

SECTION F–BUDGET JUSTIFICATION

Personnel: As was pointed out in the technical review of our experiment (successfully passed in May,2000), there is a definite need more full-time people at the post-doctoral fellow level to finish constructionof our production UCN source and the β-asymmetry spectrometer. We propose, therefore, to hire anadditional post-doctoral fellow for the next two to three years (only), to augment our current researchteam. This will ensure at least one full time post-doctoral fellow stationed at Los Alamos at all times toassist with source development, depolarization studies, and to participate in general run preparation at LosAlamos, and one post-doctoral fellow who is available to oversee characterization of the static fields inthe polarizer/AFP spin-flipper, implement a resonator and map the rf field, develop tests and models ofdepolarization on material surfaces, and assist in detector development (primarily for proton detection).This second post-doctoral fellow, stationed primarily at NCState, will be supported in part by the physicsdepartment.

At present, our plan is to support one graduate student from Princeton (Chen-Yu Liu) for the next twoyears, to work on this project. She has already contributed a critical publication, developed a new diag-nostic tool to measure the ortho/para ratio in solid deuterium, and helped us to develop new possibilitiesfor superthermal sources. She plans to work primarily on the polarizer/AFP spin-flipper next year, and tocontinue her theoretical investigations. While she is on leave of absence from Princeton, we are only re-sponsible for her stipend. We plan to support one other graduate student from the NCSU physics programto work on UCN spin manipulation, as well as contributing to the β-asymmetry measurement as it beginsto yield data. Two other students will also contribute to this project: S. Wang will recieve his support fromthe Nuclear Engineering department, and S. Hoedl will be a collaborator.

Travel: Our work requires extensive travel funds. We have reduced our lodging costs by a factor oftwo to three by maintaining an apartment (for $600 per month) in Los Alamos. This amounts to a fixedcost of $7200 per year. Each month, on average, there are one or two trips taken by some member of thecollaboration to Los Alamos. From our previous two and a half years of experience, we make a crudeestimate of the average cost per trip of about $550 (the Los Alamos trips can be made quite inexpensivethrough the use of the apartment and minimizing per diem charges), giving us a yearly domestic travelexpenditure of about $10,000. We are therefore requesting a total of $17,200 per year for domestic travel.We also typically participate in one measurement per year at ILL and attend one or two internationalconferences. These trips are expensive, so, once again based on our previous experience, we request$5,000 per year for international travel.

Equipment: We will be responsible for construction of several large pieces of equipment, includingthe polarizer/AFP spin-flipper for the UCNs (and instrumentation required to characterize the magneticfields within the spin-flipper) and low energy proton detector development. These projects, as well asour ongoing contributions to source development and depolarization studies at ILL, require about $3,400per year in materials and supplies, and $20,000 per year in equipment. The equipment can roughly bedivided into two categories: polarizer development and detector development. The digital scope, filterand frequency synthesizer are a part of a flexible, pulsed NMR facility we plan to construct to measuremagnetic field inhomogenieties to high precision inside our polarizer/spin-flipper (almost identical to onein use by the Princeton atomic physics group). Since the natural width of the NMR line in water (1/T2)is about 30 Hz and the gradients we wish to measure have widths of about 4 kHz, we should be ableto characterize our gradients well. From experience we expect ample signal from cells with dimensionsof 1 to 5 mm, making high resolution spatial scans possible. We already have, in our collaboration, thenecessary rf amplifier, and the few necessary rf circuit components can be built or purchased as supplies.We note that the scope is a general purpose instrument which will also be quite helpful in our detectordevelopment efforts and as a data-acquisition system for some applications.

The dry pumping station, ion source and power supply are a part of a proton detector development

1

program we are interested in initiating. All that is required is about 100 protons/sec, at energies of about20 keV, incident on our detectector geometries. If we use thin carbon “converter foils”, we will requireacceleration fields beyond these foils of about 40 keV. The proposed equipment budget should permit usto pursue this promising project.

The Ar+ laser is useful for characterization of source gases, and represents the only piece of equipmentnot covered by polarizer development or detector development. Please see below for a breakdown of theexpense for each piece of equipment.

Miscellaneous: We also include $1,500 per year in publication fees, and $3,000 per year for tuitionfor the NCSU student (the “other” line item).

Cost Sharing and Other Support: The NCState physics department is providing $28,200 per yeartowards the support of a post-doctoral fellow. The nuclear engineering department has pledged support forone graduate student, S. Wang, for one year, with continued support subject to the availability of funds.

Permanent EquipmentJanuary 1, 2001 – December 31, 2001

1 1 1GHz Digitial Scope with 2 Mb/chan memory (Model LC574AM)

LeCroy Research Systems700 Chestnut Ridge, NY 10977-6499

(914) 578-6013 $18,900

Total $18,900Permanent Equipment

January 1, 2002 – December 31, 2002

2 1 Two channel High Pass / Low-Pass Butterworth Bessel Filter (Model 3940)

Krohn-Hite Corporation255 Bodwell StreetAvon, MA 02322-1161

(508) 580-1660 $2,700

2 1 Frequency Synthesizer (Model PTS-160)

Programmed Test Sources, Inc.9 Beaver Brook RoadLittleton, MA 01460

(978) 486-3400 $6,225

2 1 100mW 488nm Argon Ion Laser(Model NLC 800A)

National Laser175 West 2950 SouthSalt Lake City, Utah 84115

(801) 467-3391 $6,599

2

3 1 3-Axis Flux-gate magnetometer (Model 520)

Applied Physics Systems1245 Spacepark WayMountain View, CA 94043

(650) 965 - 0500 $5,800

Total $21,324

Permanent EquipmentJanuary 1, 2003 – December 31, 2003

4 1 10W 100kV Reversable Polarity Power Supply (Model SL)

Spellman475 Wireless Blvd.Hauppaugne, NY 11788

(631) 630-3000 $3540

4 1 Duoplasmatron Ion Source (Model PS-100)

Peabody ScientificP.O. Box 2009Peabody, MA 01960

(978) 535-0444 $9,500

4 1 Dry Pumping Station consisting of:A70 MacroTurbo Turbo pumpMV2V Diaphram pumpPump controller unit

Varian Vacuum Technologies121 Hartwell AvenueLexington, MA 02421

1 800 882 7426 $7,800

Total $20,840

3

Current and Pending Support(See GPG Section II.D.8 for guidance on information to include on this form.)

The following information should be provided for each investigator and other senior personnel. Failure to provide this information may delay consideration of this proposal.

Investigator:Other agencies (including NSF) to which this proposal has been/will be submitted.

Support: Current Pending Submission Planned in Near Future *Transfer of Support

Project/Proposal Title:

Source of Support:Total Award Amount: $ Total Award Period Covered:Location of Project:Person-Months Per Year Committed to the Project. Cal: Acad: Sumr:












Source of Support:Total Award Amount: $ Total Award Period Covered:Location of Project:Person-Months Per Year Committed to the Project. Cal: Acad: Summ:

*If this project has previously been funded by another agency, please list and furnish information for immediately preceding funding period.

NSF Form 1239 (10/99) USE ADDITIONAL SHEETS AS NECESSARYPage G-

Albert Young

Low Energy Nuclear Physics Using the Princeton Cyclotron,Lasers and Ultra-Cold Neutrons

National Science Foundation667,000 08/15/98 - 02/01/01

Princeton University9.50 0.00 0.00

Development of a Polarizer/Adiabatic Spin-Flipper forUltra-Cold Neutrons


North Carolina State University0.00 0.00 0.00

US-Japan Cooperative Science: Optical Pumping of HighDensity, Low Temperature Gases: Exploring New Applications


Princeton University0.50 0.00 0.00

Nuclear Structure Research at the Triangle UniversitiesLaboratory

U. S. DOE530,000 05/05/00 - 05/04/01


A Measurement of the Neutron Beta-Asymmetry Using Ultra-ColdNeutrons Produced in a Superthermal Solid Deuterium Source



11





















Charles Mayo

A New Paradigm for Automatic Development of Highly ReliableAutomated Control Architectures for Future Nuclear Plants

U. S. Department of Energy291,736 10/01/99 - 09/30/02


Coincident Prompt Gamma Neutron Activation Analysis

U. S. Department of Energy264,959 10/01/98 - 09/30/01


22





















Bernard Wehring

Experimental Study of Ultra-Cold Neutron Localization andSub-barrier Penetration

U. S. Department of Energy, NEER123,652 07/01/98 - 06/30/01

University of Texas at Austin0.00 4.00 0.00

33

SECTION H — FACILITIES AND EQUIPMENT

NCState physics department offers a number of resources to our project, with a cryogenicslaboratory for nuclear targets, extensive laser laboratory resources, two computing clusters andplentiful access to a supercomputing facility. The 1 MW PULSTAR research reactor facilityat NCState provides us with a source of thermal neutrons for radioactive source fabrication, aswell as expertise in neutron and gamma transport issues. Finally, the NCState University physicsprogram shares, with two university partners, a unique, synergistic relationship with the TriangleUniversities Nuclear Laboratory (TUNL). Although the most valuable resource at TUNL may bethe pool of excellent students it attracts, it also has a very strong infrastructure for low energynuclear physics research, making TUNL investigators ideal collaborators in demanding researchprojects.

NCState Physics DepartmentWe bring, from our effort at Princeton, considerable laser resources, including low power

diode lasers and an ND:YAG pulsed laser, optics, and numerous detectors. We now have a high-throughput Raman spectrometer with a cooled PMT for photon counting applications. Theseresources will be augmented through collaborative efforts with the NCState optics group (prof.H. Hallin), giving us access to Ar 5 and tunable Ti:saph laser systems as well. These resourcesprovide us with tools for optically probing the composition of our source materials, and may inthe future be used to evaluate the concentration of defects and cracks in cryogenic solid samples.

A major piece of equipment we will supply for the experiment is the polarizer/spin-flipperfor UCN. This instrument is currently being fabricated by American Magnetics, Inc., and shouldbe available early next year. We also have access to a cryogenics laboratory at NCState, with adilution refrigerator at NCState, as well as our own 1K optical cryostat.

The physics department has access to at least two Beowulf clusters and large allotments oftime on a local supercomputer facility. This is especially attractive to students on this project,as it provides them with extensive computing resources to assist in routine laboratory chores, aswell as compute-intensive tasks.

PULSTAR 1MW Research ReactorThe PULSTAR facility at NCState provides unique access to a resarch nuclear reactor. With

a flux of 1013 neutrons/cm2s at the face of the core, it is possible to create calibration sourcesof radioactive Xe sources with a few hours of irradiation. These sources can be produced andshipped to Los Alamos when needed to for in situ calibration of our beta-asymmetry spectrom-eter. This facility will also provide support for a student working on this project, as well asexpertise in neutron and gamma transport which we plan to utilize in constructing our spallationUCN source.

TUNLTUNL is one of the best equipped and staffed low energy nuclear laboratories in the country.

There is also extensive infrastructure for cryogenics (there are two functioning dilution refrig-erators at TUNL), large machining projects, electronics, and detector development. Access to asubstantial pool of well-qualified and interested students is one of the great strengths of this labas well. There are also some computing resources available.

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