a +i,:++++° ++0. _/.i +/_.+_,_+_+++

s+,+rs++n°+su+,,oo4_"+ ++_+++:_++?__ +"_:('+i:.++_' _ lss°ciati°n f°_ +of_+_at_°nua+d Image Management

+"@._+_++++++ ' ++,_+_+ +rx,++0>2" "+_% ++++_:;++"_

e_ ++++_-._'.. MPlNUFPlCTUREOTO IqITM ST_NDRRDS /_"x'b'_.. +*'++'.++BY RPPLIEO IMRGE. INC. (b_._% +_

..Calculation of _uou Background

o

The _on background from charged pion and g decay was calculated from

ZSK production data [3.8] ac center of mass energies of 31 and 53 C_V. Special

care was taken in parameCrizing this data co be sure the behavior ac high trans-

verse momentum PT was correctly described, since event selection depends ac

least in part on htSh-pT muons. Comparison of the model with data ac rapidity

ym0 are shown for pions and K's in figs. _v-la and IV-lb. The model also works

well for nonzero y ouc co very near the edge of phase space.

d2 a/dpdpTLaboratory cross sections were chart calculated with this paramac-

rizacion on a grid of p, PT" In each bin of this srid the fraction of pion or

g decays per meter ta then m/Ccrp), where T is the lifetime of the decaytns

particle of mass m. In each bin of P'PT of interest a number of monte carlo

decays (T -_ _v, g _ _v) wart seneraced proportional to the number of parent

decays in the bin. The resultlns intesral muou spectra are plotted vs. PT in

lisa. 9,10 for several cuts ou lab momentum p. Note chat the contributions

from pion and K decay are comparable for PT > 1.2 GeV/c.

An independent check on this calculation was provided by a cape [12 ]

of 360 GeV _'p bubble-chamber events. Charged cracks from these real events

were assumed to be pious, and monte carlo decays were generated. The muou yield

from this approach agrees with the above calculation to better than 10Z°

For the background estimates in Section D, i_ is necessary co know the• °

number of muons from secondary interactions in the emulsion passing the muon

P'PT cuts° The lab momentum spectrum of pions from 800 GaV interacttous is

known from the production model described above. It was assumed that this modal

" is also approximate1)- correct for interacting pions down to 10 C_eV/c, and. the

_.'

|Lll ,6

t.

muon background program was run for "beams" with selected momenta between 10

and SO0 GeV/c, corresponding to the interacting secondaries. The yield of muons /I

passing the cuts for each such bin of secondary momentum was then weighted I

by the momentum spectrum of pions from 800 C,eV interactions. The largest coutrib-I

ut£on to muons passing the cuts was from secondaries of o_der 100 CeV/c, which

make about 6 charged prongs per interaction. We thus estimate thac limiting

charm decay vertex candidates to < 7 prongs will eliminate 40X of this interac-

• finn background.

The probability of a muou from a secondary interaction passing the P'PT

and prong cuts was found to be 0.13 times ttmt of a muon from the primary

vertex. This number must be multiplied by the probability of a secondary interac-

tion. We assume 9 charged prongs plus 2 long-lived neutral hadrons per 800

GeV interaction, and use the pion mean free path [17] og 50 cm and an effective

path in emulsion of 0.75 cm rio obtain 0.165 secondary interactions per event.

o o o. "-:0 " -- 0

• (_Aeglqw) dp/.op 3j-

•. A-69

REFERENCESi ,

_o

1. N.Ushida et al., Phys.Rev.Lett. 4__5, 1049(1980); N.Ushida et al., Phys.Rev.Lett. 4__5,1053(1980).

2. S.M.Errede, Ohio State University Ph.D. Thesis(in preparation).

3. M.J.Gutzwiller, Ohio State University Ph.D. Thesis(1981).

4. D.Andrews et al., Phys.Rev.Lett. 45, 219(1980);G.Finocchiaro et al._ Phys.Rev.LetC. 45, 222(1980).

5. M.Kobayashi and K._'_skawa, Prog.Theor.Phys. 4_9, 652(1973).

6. See, e.K., John Ellis, "Status of Gauge Theories," CEEN preprlnC Th-2701(1979);S.K.Nandi and K.Tanaka, Phys.Lett. 9_._, 107(1980); J.A.Harvey, P.Ramond andD.B.Reiss, Phys.Lett. 92B, 309(1980).

7. H.Tye, "B Decays in the Weiuberg-Salam Model," Cornell preprinC CBX-81-9(1981).

8. E.H.Thorndike, "First Results on Bare b Physics," Proceedings of XXInternational Conference on High Energy Physics, Madison Wisconsin(1980),P.705; CLEO collaboration, "Charged and Neutral Kaon Production at theUpsilon 4s," CLNS 81-483(1981). It should be noted, however, that thelarge kaon sisal at the upsilon 4S is not unambiguous evidence for dominantB_ charm(B.Gittelman, private communication), so that this upper limit on Blifetime is not rigorous until this important experimental question is settled.

9. V.Radeka and R.A.Boie, IEEE Trans.Nucl.Sci.2__7, 351(1980).

10. See, e.g., review by J.N.Marx in "Proceedings of Summer Institute on ParticlePhyslcs," SLAC Report No.239(1981), p.215.

11. S.L.Stone, ecal., Nucl.Inst.and MeCh. 15__1,387(1978); See also Ref.14 .

12. We wish to thank J.Whltmore of M/chlgan State for providing us a tape of360 GeV ,'p events from the 30-Inch bubble chamber. For 800 GeV deslgnstudies, these events were given an appropriate Lorentz boost, and wereaugmented by extra tracks generated by Monte Carlo to give the correctaverage multiplicity. Neutral pions(and their decay gammas) with the same

P' Pt distribution as charged tracks were also generated by Monte Carlofor each bubble chamber event.

13. The EGg calculations were performed w_th lead rather than tungsten becauselead parameters were '"aard wired" into the program. Tungsten radiators willgive even less shower spread than lead.

14. See, e.g., review by H.A.Cordon and S.D.Smith in "Proceedings of SummerInstitute on Particle Physics," SLAC Report No.239(1981), p.241.

15. T.A.Gabriel and _.Schmidc, Nucl.Instr. and MeCh. 13__4, 271(1978).

16. A.Zichichi, in talk presented at Physics in Collision Conference,Blacksbur8, Va.(}Lay, 1981).

17. The measured interaction mean free path for 20.9 GeV protons in emulsion is35.5 _ 0.8 cm (J.Hebert, private communication). The M_T for hlgh energyplons will be larger by a factor of about 1.5.

18. B.Alper et al., _ucl.Phys. BI0____O0,237(1975)

19. J.Kirkby, "Review of e+e- Reactions in the Energy Range 3 to 9 GeV," inProceedinss of the International Symposium on Lepton and Photon Interactions,Fermilab(1979) p.107.

20. H.Winzeler, Nucl.Phys. 69, 661(1965).

. .. :':0

, , References continued "' +-A-_Oeh

4. /[-' .

• v _q_,

• ° ,;

21. S.l.Amendolia'" et al., "A Multtelectrode Silicon Detector for High Energy"" Physlcs Experiments," ¥1SA 80-2(1980); Nuci.lhsC. and Mech. _176,457(1980). O

22' - E.H M.HeiJne. el: al., "A Silicon Surface Barrier Mtcrostrip Dec"ec_£Dr Designed "'• , . _. , . .

• _or_..._o_.HiShEn.rsyPhy,_cs,"C_IS.FI_,_ 80-6(.1980);Nuc1,_nsc.r..._dMec_,_I___7.8... .

23. J.B.A.England el: al., "Capaci'taCtve Charge Division Read.-Ou.c.wiCh a Silicon 'Strtp Detector," CEI_-EP/80-218(1980).

. _ r"

• O

" _ '.'" B-I

APPENDIX B

AGREEMENTE-653

"MEASURINGCHARMANDB DECAYSVIA HADRONICPRODUCTIONIN A TAGGED

EMULSIONSPECTROMETER"

This is an agreement between the Fermi National Accelerator Laboratory

and the experimenters of E-653. This agreement pertains to the completion

of data taking and analysis at Fermilab for an experiment which tags charm

and B particles by observing their decay lengths. It contains an enumera-

tion of the major items needed for proper execution of this experiment.

A summaryof current experimental objectives is included as Appendix

I, a list of experimenters as Appendix II, experimental layouts as Appendix

III, emulsion facility requirements as Appendix IV and PREPand computer

requirements as Appendix V.

A. Personnel

1. Experimenters are given in Appendix II, together with a summary

of other experimental commitments.

2. Nevtlle W. Reay ts the scientific spokespersonfor this

experiment.

3. The deputy spokespersonis Ronald J. Ltpton.

4. The presently assigned liaison physicist for Fermtlab is

B. Beamb

1. Energy: Up to 1000 GeVdiffracted protons. A 5-150 GeVvariable-

energy low intensity beamalso ts necessary for in-place

• caltbration.

2. Intensity: Variable between103/second and lO7/second.

3. Spot Size: 3K3 mm2 with reasonablyuniform density and divergence

less than 1 mllliradian.

4. Halo: Less than I/3 of the central beam flux within an area 9x9

Inches2 centered on the beam. For example, if central beam intensity!

is 2000 particles/mm2/sec,the halo must be less than 0.03 particles/

mm_/sec. This may require extensive passive and/or active muon

shielding.

5. Beam Height: At least 2 meters above the building floor.

6. Momentum Spread: Tagged to I% rms by hodoscopes.

7. Beam Particle Tagging: Particle identificationmay prove desirable

should experimentalresults indicate non-protoninteractionsmight

be interesting.

8. Access. Access is needed hourly to change emulsion. A designated

yellow access area with a beam plug controlled by the experimenters

Is crucial. Tuning the beam from the switchyard for low rate :

emulsion runningwould be prohibitivelycostly in time.

. C. Equipment

Note: The values of presentlyexisting items are shown in parentheses.

I. The Fermilab experimentalareas departmehtw111 provide:

a. A new N-3 charged beam'in the neutrino area satisfy-"

Ing the specificationsof section B.

b. A building with floor space at least 40 feet transverse

to and 60 feet along the beam line. This clear area

must be maintained at least to a height 18 feet above the

bulldlng floor. The bullding should be temperature-con-

trolled to -+5°Cwith less than 50% humidity. Dust control

also is requlred,as is an In-house W.C. A minimum of :

B-3

70 KVA of llO VAC and 208 VAC power should be provided.

c. Within the building a portionwill be defined by a uni-

strut and herculite structureprovided with light and

power to function as a clean assembly area for the Liquid

Argon calorimeterno later than July I, 1983. Further, an

I-beam support structure for a I0 ton lift capability chain'

hoist with 15-foot span transverseto the beam line will be

required for Argon calorimeterinstallation.

d. Four portakampsor equivalent area will be required during

setup and running for fast electronics,computers, repairs,i

short term storage and office space.

e. Constructionof a Fermilab emulsion developing facility and

an upgrade of the existing Fermilab emulsion pouring facility

as specified in Appendix IV. This requires the E-531 village

space plus additions for the developing laboratory.

f. 193 tons of muon and calorimetersteel, already existing in

E-531.

g. "Square" Torold: 90K

Estimate I00 tons @ $600/ton for cutting and machining,

$5,000 for coils, $I0,000 for the power supply and $15,000

for mlsc. controls,etc.

h. Continued use of the SCM 104 magnet currently on loan to

Ohlo State by ANL. Technical support also will be required

while modifying to a smaller gap an_ for field mapping.

Pole tip modificationswill be provided by experimenters.

Associated water, power and field monitoring as provided

during E-531 also are required.

I. Beam-line control and display unit.

_I.Rigging for

i) SCM 104 magnet

ll) Gamma calorimeter

Ill} Hadron calorimeterand muon steel

iv) Portakamps

v) Computer installation

k. Surveying for equipment (twomen for one month)

2. The Fermilab ComputingDepartmentwill provide: !k

a. PREP electronicsas estimatedin Apendix V.a.

b....Peripheralsand maintenance for a VAX/750_computingsystem, !

includingtwo 6250 magnetic tape drives, as specifiedin

Appendix V.b.

c. Computer time equivalent to I000 hours on the Fermilab

CYBER/175 computer

3.. Fermilab Research Services Division will provide:

a. 4000 channels of Liquid Argon calorimeterreadout elec-P

tronlcs of the type now being oesigned by T. Droege for E-706

b. 1000 liter Argon storage dewar and vacuum-lnsulated

transfer line

c. 5000 liter Nitrogen storagedewar and vacuum'insulated

transfer line

d. 02 monltor

e. Argon gas purifier

4,. U. of California at Davis experimenterswill provide:

a. 12 double-gap dr|ft chambers 240K

b. East electronics EOK

• , , ]3-5

c. Minicomputer 40K

d. Operating costs • 50K

SUBTOTAL 350K

5. Carnegie-Mellon Experimenters will provide:

a. Liquid Argon calorimeter assembly, consisting of:

foam dewar, 28 radiation length detector assembly,

lifting & positioningsystem, & calibrationsystem 356K

b: VAX/750 computingsystem . 60K .., v

'c. Small computer/devicecontroller 40K

d. Stands, cables, misc. equipment (3OK)

e. Droege electronics development/test support 20K

f. Operating funds 50K___ _ = i

EXISTING VALUE (3OK)

NEWCOSTS 526K IfL ,,,, ,, ,- • i i

5S6K• SUBTOTAL

6. The Nagoya and Osaka-Kobe Emulsion Collaborations will provide:(We assume an exchange rate of 250 yen per dollar)

a. 100 liters of Fuji Emulsion @ 5K/liter £OOK

b. Associated chemicals for pouring and processing 60K

c. Emulsion fabrication hardware (5OK)70K

d. Emulsion scanning and measurement, including at least

25 people and manual, semiautomatic and automatic scanning

capability. (The400X includes costs for an automatic

B-6 .... o.

and additional semiautomaticscanning stations.) (864K)400K

e. Precision stand with electronic readout (exposes

emulsion in strips by moving it through the beam) 160K

f. SSD prototyping 36K

g. Operating funds . 25K

EXISTING VALUE (gI4K)

NEW COSTS 1251K

SUBTOTAL 2165K

7. University of Oklahoma Experimenterswill provide:

a. Spectrometermagnet modification, participation

In field mapping 8K

b. Eight solid state microstrip beam detectors,with'

mounts 36K

c. 2000 channels of SSD readout, @ 50/channel lOOK

d. Eight beam drift chambers,with mounts 20K

e. 100 DC readout channels, @ 80/channel 8K

f. 14 planes of hadron-calorimetertube chambers, @

2K/plane E8K

g. 1400 tube chamber amplifiers,@ 20/amp 28K "

h. Time of flight counters, 50 scintillatorsand

I00 photomultiplierswith bases 65K

I. Minicomputer / 40K\

J. Operating funds 50K i

SUBTOTAL 383K

" ..... B-7

8. The Ohio State University experimenters w|11 provide:

a. Scintillator counters

t) Muoncounters from E-531. 90 counters @6001counter (54K)

ti) TPtgger counters 3K

1t._) 25 tubes and bases 1OK

tv) Various support stands 5K

" b. Upstream spectrometer solid state mtcrostrip detectors

1) 21 detectors wire-bonded to circuit boards @8K/unit 168K

tt) Electronics, 10,000 ltnes @50/line (including

amplifiers, analog multiplexing, cables, power

. supplies, etc) 500K

ttt) Precision support stand, wtth RF shield.and tem-

perature control, on-line position readout) 30K

c. Ortft chambers

t) Upstreamspectrometer;:chambers,two ..

measuring X and one Y, each sampltng4 times along

the beam, @4K/chamber 12K.

tt) 4X, 4U, 4V chamberseach sampltng4 times along

the'beam tn the central region and 2 times along

.the beamtn the wings, @6K/chamber 72K

ttt) 1400 readout ltnes@ 80/ltne, tnclOdtng interface 112K

tv) Precision structure and pressure vessel for drift

chambers, Including on-ltne po_ttton readout 40K

B-8 .... ,

. v) Readout for Davis chambers,800 channels @

d

$100/ channe1 (80K)

d. Fast electrohics (2OK)20K

' e. Eight megabytebuffer memorystorage, including

temporarybuffers,interfaces,etc. 75K

f. Minicomputer 40K

g. Operating costs 50Kj_ j ii

EXISTINGVALUE(154K)

NEWCOSTS l 137Ki,, i i

SUBTOTAL 1291K

Summar_of ComputingAlV,alilab.leformOlf.f!ill],e,Anal_/sis

1. Universityof Californiaat Davis

VAX II/780 1200 hr/year

2. Carnegle-Mellon

VAX I1/780 I100hr/year

3. The Ohio StateUniversity..

• Amdahl470 500 hr/year

4. Universityof Oklahoma

VAX 11/780 1200hr/year

IBM 3081 300 hr/year

.' .... B-9

D. Fundtng

1. Funding SummaryExtsting Value NewCosts Total

Ferm|lab ExperimentalAreas Department

Fermflab ComputingDepartmentFe_nllab Research ServicesDtvtsion

SUBTOTALS

University of California, Davis 350K 350K(Not shownare lOK of funds already

spent prototypJ ngFy83drift31oKchambers)FY 84 40K

Carnegie-Hell on University (3OK) 526K 556KFY 82 20KFY 83 39¢KFY84 ll2K

Nagoyaand Osaka-KobeCo11aborat ions (914) 1251K 2165K

FY 82 156KFY 83 350KFY 84 400KFY85 .345K

• University of Oklahoma 383K 383K(Not shownare 43K of funds alreadyspent prototyplng SSD's)

FY83 383K

The Ohto State University (154K) 1137K 1291K- - - (Not shownare 200K of funds already

spent pr.ototyptng SSD's and drift• chambers)

FY 82 95K(Dependenton 1982 supplementaryrequest submitted to DOE)

FY83 570KFY 84 462KFY85 lOK

m i ml I III III I _111 IImlll I I II i

SUBTOTALS " (1098K) 3647K 4745K

TOTAL

o.,. .

• B-IO .....

2. The University of California at Davis will provide funds for

items listed in C.4 out of FY 83 and 84 funds provided by DOE,

Contract DE-AMO3-76SFO0034.

3. Carnegie-MellonUniversitywill provide funds for items listed

in C.5 out of FY 82, 83 and 84 funds provided by DOE, Contract

BIN DE-ACO2-76ER03066.

4. The Nagoya and Osaka-KobeCollaborationswill provide funds for

items listed in C.6 out of FY 82, 83, 84 and 85 funds provided

by the Japanese government.

5. The University of Oklahomawill provide funds for items listed

In C.7 out of FY 83 funds provided by DOE, Contract DE-ASO5-80ERI0629.

6. The Ohio State Universitywill provide funds for items listed in

C.8 out of FY 82, 83, 84 and 85 funds provided by DOE, Contract

• DE-ACO2-76EROI545,and the State of Ohio. •

• 7. Fermllab will provide funds for the items listed in C.l and C.2

out of FY 83 and 84 funds.

8. The budget codes of experimenters are: University of California

at Davis (BIY); Carnegie-Mellon University (CIB); Nagoya and

Osaka-Kobe Collaborations (JAA); The University of Oklahoma (IDS)

and The Ohio State University (CIA).

m

, EXPERIRENTALPLANNINGHILESTONES. " .

Dat__.ee Track ,Detectors .Ga.mmaDe.tecto _ Xuon System Fe_qt ]ab

current low-noise amps and softwarefor 1 on x 1 on sillcon :stripdetectors (SSD). Bench testof capacitive charge division.

9/82 Fit tracks tn full-size Finish design of(2.6 cm x 3.4 on) beam SSD full-depth LestBench test 5 cm x 5 cm vertex SSD.... modu!e. Study Droege

electronics prototypes.

10/82 finish studtes of- replace SCM-11-cell muon drift polepieces.chamber prototypes.

11/82 finish 1-cell prototype complete constr_ctton start mappinghigh-resolution drift of test module. Begin SCH-104.chamber. Prepare electronics testing on ft.LAHPFbeamtests,

•I

1/83 Butld full-size DC proto- Test full-depth module finish full- start butldtng _type. Test final 5 x 5 cm at SLAC. Start mechanical size prototype, emulsion-SSD. Begin readout construction on full-sized processing lab,el ectronics construction, dewar,

3/83 Bench test full-size DC. design limited streamer start torotdBegin construction of tube (LST) array for construction,15 modules, hadron calorimeter.

Finish p-trigger software.

4/83 Begin PC board start experimentalfabrication, halI construction.

5/83 Set up DC assembly. line and begin

building 12 modules

7/83 Assemble SSI), electronics ftntsh cryogenicand cables onto precision controlsmounts.

Date Track Detectors GammaDetector Huon System Fermil abi i ii i

8783 recetve LeCroy high- build clean hut for assemble LST Hove SCH-104,resolution readout, detector assembly in toroid, range steel

experimental hall. into building.

10/83 Begtn equipment Begin detector assembly, test DCmodules Install VAX ininstallation, with computer, counting room.

11/83 begin calorimeter complete PREPtests, allocation.

Deliver firstbeam for focusIhalo studies.

1/84 begin DC installatlon.

;£/84 Detector complete.

4/84 INSTALLATIONCOMPLETE;-BEGIN SYSTEMCHECKOUTi-J

Summer, 84- E653 FIRST DATARUN

o

.. °

Ii

• '' " B-13

This Agreement is mutually acceptable both to the experimenters

and Fermilab. Circumstancesand needs may change as the program

develops. This Agreementmay be amended,if necessary.

Peter F. Koehler (Date)Fermi National Accelerator Laboratory

Nevllle W. Reay (Date)Ohio State University

z _ - , i _ ,

Ronald ,I.Lipton (Date).Carnegie-MellonUniversity /

' B-14 .... .

APPENDIX I

EXPERIMENTERSGOALS

E-653 is a collaborationof scientists from the United States

and Japan which will study the hadronic production of charm and beauty

using a hybrid emulsion spectrometer.

Lifetimes as short as 10"15 seconds can be measured in emulsion.

The downstream spectrometerwill be used to preselectand locate interest-

ing events from interactionsin the target produced by protons of the

highest availableenergy. The minimal trigger will require a several GeV

muon originatingin the target. Short-liveddecays containing the muonwill be tagged off-line by a very high resolution vertex detector composed

of 21 planes of slliconmicrostrip detectors (SSD), with an estimated

precision for resolving secondaryvertices of 8 microns RMS transverseto

the beam direction ahd 350 microns RMS parallel to it. The emulsion targe_

will then be scanned for these decays. The anticipatedyield from a lO0

liter exposure is 15,000 charm and 200 beauty particles. In addition, the

experimentwill have a several event/nanobarnsensitivityfor tau decays

and for new particle states with lifetimesin the range 10"11 to 10"15

seconds.

A primary goal of the experiment is measuring both charged and

neutral B-meson lifetimes,which most theories predict are so short that

they can be observed only in emulsion,

Physics ef tnter,=st in the charm system ircl,d=.s measuring l i fe-ral=.=times very precisely and setting stringent limits on DO-D° mixing, Wewill

- " be able to study branching ratios and excited states of charmed particles

in a nearly background-freeenvironment. Furthermore,we shou.ldbe able to

locate several dozen F . T . X sequentialdecays.

The apparatus is designed to have applicationsbeyond that pro-

" posed for E-653. In particular,the very high resolution of the SSD vertex

detector makes a study of charm or similar particlesfeasible without a

visual target under certain circumstances. The copious yield of events

from E-653 should prove very fruitful in designingfurther experiments.

APPENDIX II

E-653Participants

Universityof Californiaat Davi's

I(o,W.*Lander, R.Moktarani,A.Rumiansiv,G.Yager,P.Post DocSecondGraduate Student

*50%on PEP-9during1983.

CarnegieMellonUniversity

Edelstein,R.*Forsyth,C.Gamarnlk,K.Lipton,R.+Nichol W.Russ, _:+Winkler, L.Post Ooc

*On sabbatical leave 1982-83.. +Quartertime commitment.tofinishE-515analysisduring1982-83.

KOBE-OSAKACOLLABORATION

KobeUniverslt_

Fujloka,G.Fukushima,H.Hara,T.Takahashi,Y.Tsuzukl,Y.Yokoyama,C.

OkayamaUniversity

Moriyama,K.Shlbata,H.

B-16 ....

APPENDIX II

Page 2

Osaka City University

Kusumoto,O.Noguchi, Y.Okusawa, T.Teranaka,M.

Science EducationCenter of Osaka Prefecture

Okabe, H.Yokota, J.

All except Okusawa have a half-timecommitment to complete E-531horizontalemulsion scanning in 1982-83. Okusawa will devote 50% timeto E-653 and 50% to Tristan.

NAGOYA COLLABORATION

Aichi University of Education

Ushida, N.

University Of Gifu

Tasaka, S.

Nagoya Un!yersit_

Chiba, K.Hoshlno, K.Kaya, R.Hiyanishi, M.Nakamura, M.Niu, K.Niwa, K.Ohashi, M.Shibuya, H.Torii, N.Yamakawa, O.Yanaglsawa, Y.

Toho U_niversity

Kazuno,M.

Yokohama National University: -- -- ii ,,

Maeda, Y.

"° •

B-17e' t • e t

APPENDIXI IPage 3

Prior to summer, 1983, all of the above will have a 60g commitmentto E-531 second run analysis, a 15% commitment to E-653, and a 25% com-mitment to CERNWA 75 and miscellaneous smaller experiments. Aftermid-1983, E-531 analysis will be complete. Integrated over all followingtime, the commitment wtll be 60% to E-653, 40% to WA75 and other smallerexperiments. Upon receipt of E-653 exposed emulsion, the commitment tothat experiment will increase to 70%.

University of Oklahoma

Bol, K.Kalbfleisch, G.Skubic, P.White, J.Willis, S.Post Doc

All of the above are 3/4 time on E-653 and 1/4 time to a varietyof commitments.

Ohio State University_ ,i, _ .-

Dunlea, O.GauthJer, A.

• Kalen, O.Kuramata, S.01eyntk, G. t"Reay, N.Reibel, K. tStdwe11, R. t"Stanton, N.

Has a 1/4 time commitment to compiete E-531 analysts tn 1983.

Solid State Detector prototyping for a CERNLEP-3 experiment is proceedingat lower priority until completing the first run of E-653.

• •

APPENnIXI II, CONTINUED

- 4 -5 -2 -I 0 I 2 5 4 5 6 7 8 9 I0 II METER

E655 ELEVATION VIEW

• o

i i i i

. B-20 '

APPENDIX IV

Necessity of Pouringand Processing Emulsion at Fermilab

In Experiment 531, all emulsion modules remained in place for months.

In Experiment 653 the exposure time is much shorter, an hour for the

vertical modules and a few pulses for the horizontalmodules. Because of

stringentrequlrements in spatial registration,the horizontalmodules will

be marked by x-rays at the time of exposure, necessitatinga somewhat

fragile design. Uhless the pelliclesare removed and stuck to lucite plates

quickly after exposure they can easily be distorted by changes in temperature

and humidity.

Further, if we pour the emulsion just before exposure and process

Immediatelyafter, we can avoid unnecessarybadkground tracks and get higher

grain density. This is extremely important for high track _ensity exposures.

By improvingthe Fermilab's pouring facility and constructinga pro-

. cessin.qfacility,we also can avoid problems associatedwith transportation

(refrigerationduring moving, etc.). Most importantly,we can concentrate

our manpower at Fermilab.

Improvementof Pouring Facility

For the second run of E-531, we produced about 30 liters of emulsion

target in one month. This ability is enough for E-653. However,we need to

make improvementson uniformityof air flows and humidifiers.

Constructionof Processin9'Faclllt¥

The processing facility requires a chiller water-coolinqsystem with a

capability of 4000 liters/day of 5 ~ 7°C water, because the solutionsmust

be kept cold to reduce distortion of thick emulsion. This makes the thick

emulsion processing system different from the system for the usual photo-

graphic films. Furthermore,thick emulsion takes longer to process. We have

to process a fair amount of emulsion at one time to reduce the total processing

time.

...... B-21

The processing of 600 pm thick emulsion hor|zontal type pellicles

has the following steps:

presoak (2 hours)

develop (12 hours)

stop (2 hours)

ftx I (2 hours)

fix II (2 hours)

flx III (4 days)

ftx IV (same tank as fix II) (2 hours)

ftx V (same tank as fix I) (2 hours)

wash (6 days)

dry I (2 hours)

• dry II . (2 hours)

• dry I I I (2 hours)

dry IV (6 hours)

• Ftx III and washing stages take longer,thus, we need more tanks

. for these two stages. With thts system wecan process 3 liters of

emulsion per day, which exceeds our E-531 rate tn Ottawa by 50%.

Based on the above considerations, the processing factltty ts

designed as follows.

o

a

Room Size Dark Room Floor* Dratn A/C Ventilation Pure Water Water** Electricity

Preparation 24' x 12' X X X X X 2 C/H 10 K1V

Processing 30' x 12' X X X X X X 2 C/H 10

klashtng 18' x 12' X X X X 3 C/H 10 KW

Drying 18' x 12' X X X X 2 C/H 10 Kk#

Chtller 12' x 12' X 4 C 70 KW

Storage 18' x 12' X

X Must be tncluded in room construction.

* floor - waterproof (water can be thrown away on the floor) Ib.)

** C/H - cold and hot water supply (15 - 20 liters/rain.)

v

"* •

,i

B-23

The Purpose of Each Room

Preparation-

Hake various solutions.

Fumes from the fixing solutton are toxic in high concentrations, thus

a large room with good ventilation is needed.

Processing-

Process the emulsion.

Washing-

Wash away the remains of fixer.

Drying-

Dry the emulsion using different concentrations of an alcohol-water

solution.

Chiller-

Houses the chiller system.

Storage-

To process 3 liters of emulsion per day, we use about 500 kg of hypo.

The used fixer (900 Liters) will be retrieved.

Used fixer will be sold to companies in order to recover the silver in Tt.

The storage room is used for the temporary storage of these chemicals and

used fixer.

COst ,,Estimate ,for,,,the,,,Proces,stng System

Chiller system $ 25 K

Tank @ 1.2 K x 17 20.4 K

Piping 5 K

Water purifier S K (2-31iters/min.)(7~ 8 MIZ-cm)a

Butldtng

Electricity

Water Supply• .:

G_ B-24 "BUILDIN AYOUT " "

50' " 12" 18'i iiii i ii - iiI [ I ii •................ ,, • _,

PROCESSING ROOM CHILLER WASHING

12' 9 TANKS 4 TANKS(DetQil below)

i illI l I l I III i................ • -- __

-4' CORRIDORi .... i i i i ii

PREPARATION STORAGE DRYING

12' 4- 5 DRUMS TO CHEMICALS 4 TANKSMIX SOLUTIONS USED FIXER

•, ,.II [ _ , .... ill

24' 18' 18'

• PROCESSING ROOM DETAIL

50'• I Ill I II I I I _ Illlll I I I I . II II Ill

IFI I i;1,_1TABLE- ,2,3%

DOUBLE DOOR

This room must be a dark room with a waterproof floor and drains.

APPENDIXV.A

pREP.REQU! REMENTS•

Item Hodel # # Needed Untt Cost Totall

PH HV Supply LRS 4032 6 $4000 $24.0 K

8 channel disc LRS 620D 30 700 21.0 K

12 channel ADC LRS 2249A 18 1400 25,2 K

8 channel TDC LRS 2228A 28 900 25,2 K

CAHACcrate & PS 7 1800 12,6 K

Type A cont roller 7 850 6.0 K

1,5 m CAMACcables 6 200 1.2 K

vls. branch terminator JoergerVBT I 400 0.4 K

quad disc LRS 621 8 800 6.4 K

mean timer LR$ 624 2 1000 2,0. K

logtc units LRS 365AL 19 700 13.3 K

gate generator LRS 222 6 800 4.8 K

lo91c fan in- fan out LRS 429 10 500 5.0 K

12 channel scalers LRS 2551 6 1000 6.0 K

rtse time compensated LRS 825 2 1500 3.0 K5 fold disc

multiplicity log|c LRS 380 4 800 3.2 K

quad linear fan in LRS 428 4 450 1.8 K

NIM/TTL converter LRS 688 5 700 3.5 K

llnear gate LG 105/N 3 450 1.4 K

NIM crates & PS 15 600 9.0 K

PREP. (cont.)

Item Model # # Needed Unit Cost Total

NIM fans 15 100 $ 1.5 K

NIM extender 2 100 0.2 K

presetscaler Jorway1883 2 400 0.8 K

dual visualscaler Jorway1880 20 500 I0.0 K

QVT Le Croy 1 3000 3.0 K

x I0 linearamplifier LRS 612A 4 800 3.2 K

Predetbox Fermi 2 500 1.0 K

pulsegenerator 2 500 1.0 K

Neg.MWPC PS 70 channels 28,0 K(digitalreadout,computercontrolled)

Pos.MWPC PS 20 channels 8.0 K• (as above)

outputregister Jorway41 1 300 0.3 K

ADCprocessors LRS 2280 3 2500 7.5 K

24 chart. ADC LRS2285A/15 55 1500 82.5 K

CAMACextender - 2 100 0.2 K

coincidence register LRS2341 2 800 1.6 K

FASTBUScrates 5

FASTBUS/CAMACinterface 1

FASTBUScratecontroller 5

Oscilloscope Tektronix484 2 4000 8.0 K

storage oscilloscope Tektronix R 5103 1 2000 2.0 K

digital voltmeter Fluke 3 600 1.8 Ku i

$336.0 K

B-27APPENDIXV.b.

COMPUTERREQUIREMENTS _

The host computer must perform at least four separate tasks: on-ltne

event filtering, correlated monitoring, tape-writing and network handling. The

speed and memory requirements of all these tasks cannot be satisfied by a

computer smaller than a VAX/750, which will be provided tn a mtntmal configur-

ation by the experimenters. We request that Fermtlab provide additional

peripherals for thts computer, and maintain the entire host system.

Our Justification of the VAX is as follows:

The hardware trigger, which requires a muon candidate penetrating 4.5

GeV of tron absorber, wtll generate 20 events/see wtth 26 k-bytes of data per

event. With a 20 second spill once per minute and 6250 byte/inch tapes wtth

effective densities of 4800 BP], one tape of data would be produced every 13

minutes, an unacceptablyhigh rate. A factor of 4 enrichment can be obtained

from on-11ne filterlngif the host computer has sufficient speed and memory to

process an event every 150 msec. The filtered events would contain only high-

qualitymuon candidates with P >8, P_>O.2 GeV/c. Thls Is done by reconstructing

muon .candidateson either side of an iron torold and then checking for the pre-

dicted track within tight slope and position tolerances upstream, in the middle

of the calorimeterand In the spectrometerdrift chambers. The estimated

number of track candidates Is I-3 at the torold and I-5 In the predictedwindows

upstream. This filterlng task w111 be dominated by the tlme required to do the

"3 hits In 4 planes" problem In typlcal1¥8 groups of planes. Our experience

In a slmllar situation In E366 projects about 25 msec on a CDC 6600 for this

task, which translates approximatelyto 100 millisecondson a VAX/750 and 250

milliseconds on a PDP 11/45.

" The speed requirementof the filtering task Is possiblewith the VAX/750,

whlle the PDP 11/45 appears to be too slow by more than a factor 2. However, the

situationwlth the PDP 11/45 is really much worse than thls because, as we

shall show, the memory requirementsof a11 the tasks leave no room for resident,.

I

o

. B-28F4 , t e

overlays via memory management but force real overla From disk at approxi-

mately 40 msec per overlay, an intolerablepenalty.

Although the individual subsystems in the experimentwill be monitored

by the dedicated minicomputers,a considerableamount of correlatedmonitoring

must be done by the host computer due to the extraordinaryprecision require-

ments in the vicinity of the target and the continuousmovement of the emulsion

stack. It is essential, for example, to continuouslyreconstructand fit beam

tracks through the whole system of detectors. Efficlencies,global checks, event

display and precision alignmentmonitoring will require at least 26 k-bytes of

buffers and 50 k-bytes of code and array storage. In fact, it is reasonable

to anticipate that the memory requirementsof the correlatedmonitoring of

E-553 will exceed those of the total monitoring of the much simpler E-531,

which was I00 k-bytes.

Additional storage is required by the tape-wrltingand network handling

tasks, which are continuouslyactive. We have estimated the total memory

requirementson a PDP 11/45 as follows:

• "BARE BONES" SPACE REQUIREMENTS

(k-bytes) Code & Run Time Buffers TotalEnvironment

L

PDP11/45 Total Memory 248 k-byte

Operating System (RSXIlM)* -124 k-byte

[Ne ........ yie]t Available for Users 124 k-b, ,

Network Handling 40 - 40 k-byte

Tape Writing 18 26 44 k-byte

Monitor Experiment + 50 26 76 k-byte

Filtering 47 10 57 k-byte

Net Program Size 217 k-byte-- i, i , i ,i L

' " B-29

*This system ts required to support FOP,TP_N77(F4P), whosefloattng point per-

formance ts 4-11 times faster than RT-11 FORTRAN.Comparisonwith an existing

RSXllM 4,0 systemindicatesthat approximatelyhalfof the realmemorywillbe occupiedby RSX and systemservices.

+Impliesat least2 overlaysfromdisk.L i

Thus,the neededuser programspaceis nearlytwiceas largeas

is availableon the PDP ll/4S,implying(at the very least)extensivereal

overlayingfromdisk whichthe filteringtaskcannottolerate. This constraint

is liftedby the 2 M-bytememoryof the VAX.

ComputerConflguration

The experimentersintendto providethe followlngcomputerto serveas host:

VAX/750with 2 M-bytememory

RKO/ disk (28M-byte)

LargeWinchesterdisk (414M-byte)

8-11netermlnalmultlplexor

FP750floatlngpointprocessor

VMS operatingsystem

Igerequestthe followingfrom Fermilab:

2 6250 BPI magnetictapedrivesand controller

6 CltTterminals,2 with graphics(VT52/VTIO0compatible)

Line printerwith graphics

FORTRANIIcense

Systemmaintenancefor 3 years.

NOT___[:6250 BPI magnetictapesmay be interfacedvia UNIBUS,MASSBUS,or

computerbackplane.SomeUNIBUSinterfacesimposesuch severesystemload as

to crippleotherdevices. If the chosenconfigurationdemonstratesthis

problem,a secondUNIBUS-to-backplaneinterface(DW750)will be required.

.... C-I

Appendix CThe SSD Prototyping and Testing Program

_rhe SSD prototyplng and testing program has basically three goals:

a) Check charge collection,' b) Check track point resolution,

c) Check vertex reconstruction resolution.

All of the above checks have been made with the OU testing of five I c= 2 LBL

(Walton) detectors instrumented with 160 prototype amplifiers. The result is

that the detectors perform as theoretically expected. A discussion of the

basics, the amplifier design etc. is to be found in the 1981 Fermilab SSD

Workshop. I A description of the Fermilab H5 beam test (Hay-June, 1982) is

appended as a subappendix to this Appendix C.

In addition, OU and Ohio State have been cooperating on testing of 8 cm2

Centronic detectors (LAMPF beam test in progress, data taking to commence

Nov. 27--Dec. 15, 1982). In addition, six 25 cm2 United Detector Technology2

and six 2S cm Centronic's detectors square in cross-section built on three .

inch silicon disks SSD's should be in hand in two or three months: At that time

we will bench test them and subsequently beam test them. The ultimate twelve

sided regular polygonal 35 cm2 (on 3" Si disks) SSD's should be specified

and or dered early next year (with delivery expected late in the year)•

The charge collection results are shown in Figures C-1 and Figure C-2.

Plgure C-I shows the charge distribution of 46 GeV/c pions comparled to a Landau

distribution convoluted with a 0.25 £c noise distribution. The shape and the

magnitude of the charged collected (1.7 gc observed vs. 1.8 fc predicted ) agree

well. Figure C-2 shows 650 4eV/c protons in excellent agreement with the

theoretlcal shape (Landau convoluted with a momentum spread o£ 7q and a noise

of 0.2S fc). And the observed ratio of the pulse heights of 650 MeV/c protons to

o

%

i_I

l,a.

...... I .......I I ....

l

C-4 ....

550 MeV/c pions of 2.7 _ 0.2 agrees well with the theoretical ratio of 2.6.

Assuming that the spatial track point accuracy is given by the microstripe

spacing (pitch) divided by the_, the observed chisquare distribution for

the fits of straight through beam tracks for all 5, 4, and $ point 46 GeV/ce,

pion tracks are shown in Figure C-5. The average (x2/VOF) for this data is

1.2 _ 0.2. This implies that the accuracy is within (I0 _ 10)_ of the

theoretical pitch/_value including residual misalignments of the detector ar-

ray. The detector arr_saligned better than _ the pitch of 80 microns both

rotationally and translationally.

The transverse resolution of through beam tracks extrapolated from the SSD's

to the position of the veto counter is illustrated by the data in Figure C-4.

The veto would ideally cast a rectangular shadow on the downstream SSV's.

Beam divergence _orresponding to less than _ 80 _), the veto angular misalign-

merit (_ 60 _), multiple scattering in the copper target pieces ('40 _) and

the'errors in the fitted parameters (-20 _) put a slope on the edge of the

shadow of ($ II0 _). The data have a sloped box shape with a slope of "I00_.

However please note that the shadow edge goes from fully bright to fully

dark in one stripe width!

Finally multiprong interactions are observed in the SSD's. A typical three

track event is displayed in Figure C-5. The "dashes" represent stripes

connected to their own amplifiers. The letters of the alphabet represent

proportionally the charge deposited on the appropriate strip for those stripes

which have a signal larger than the pedestal plus three noise standard

deviations. The numbered lines represent the tracks. One sees that the three

tracks intersect nicely in a small region (triangle). The estimated vertex

errors from the fitted track parameters are _ .01 mm transversly and ± 0.4 mm

Iongitudally. The transverse errors are roughly independent of the event

J

!

Figure C-3

X2 Distributions6

o _ ¢o _" IO .5" I0

1_z(I co_,5 _" (ZDo_') ._,.(_.0o#.5

• •o

C-6 ....

Figure C-4

Transverse position of 46 GeV/c pion tracks at

the z-positions of the VETO counter (its "shadow").

o

C-8 ....

details for vertices close to the detector array. The longitudal errors should

be linear in the pitch, the reciprocal of the (largest) opening angle of the

tracks_ and the distance from the SSD array to the interaction point (i.e.

vertex). Alternatively, the R_tS deviation of the pairwise intersections of

the tracks from the overall fitted vertex can be examined in lieu of the

calculated transverse and Iongitudal errors for events with 5 or more tracks.

The RbtS for the transverse direction averages 20 _, as compared to the track

point standard deviation of pitch/_]'_ = 25_ in this set up. The _ for the

Iongitudal direction depends strongly On the reciprocal of the opening angle

and averages 500_ for an opening angle of 50 mr. Monte Carlo shows that bottom

and charm decays from hadronic production at Tevatron energies will have an

average opening angle between pairs of 70mr. The actual SSD's for E-655

will have a pitch of 40_. Thus we expect an _ Iongitudal error in predicting

vertices in the emulsion of E-655 of 500/2/_'2 = 200_, as advertised in the

proposal (Appendix I, page 12 ).i

The above results show that SSD's perform as theoretically expected. We

have gained needed experience in SSD'sllow noise amplifiers, charge sharing,

and the diverse software required to analyze the data from such a system. The

- - SSD's are we1_ understood. Thus we can proceed to prosecute this experiment,

- having SSD technology well in hand.

I. Kalb£1eisch, George R., "Status of Some of the Silicon Detector Developmentin the United States," in Silicon Detectors for High Energy Physics,Proceedings of a Workshop held at Fermilab, Ocotober 15-16, 1981, page 45.

•ql •

D •

• • o,

• ' • , • C-9 .. !0, 19$2.GRK/LFo

• , •

". • . "_ ' Enclosure 1 .

• " . • ..gf Appendix C . . .• Q

• * Q.

(LBL- J. Wa'Iton, R. Ely . -OU-HEP- G. R. Kalbfleisch, P. Skubic, S. Hillis, T. Hicol, R. Palmer, J. h_ite,

• N.'Ho, D. blaher_ F. bJaher, g. Palmer, L. Palmerp R. Sirochman)

", .. OU-HEP and LBL-Berkele), have continued prototype SSD testing. Eight devices

wore made in Aprl.l 1982 at LBL. Two of these are still at LBL for bench testing,

one was accidentally broken and the other five are being tested in the MS beam

..at Fermilab (E653, May 1S-June 14, 1982). Some preliminary results from 2000

: .%rlggcrs of so_.e 50.000 taken (or to be taken) are presented here.

---_V's .. " " .

• These J_rL1 1982 devices are 3 c_ diameter 1SOp thick p-type (2 Kf_cm "

• Tesistivity) silicon wafers, with 48 .stripes (each I0 _n lone) 20p wide spaced•

• on 80p centers. Forty stripes are wire bonded to the P.O. card ffanout (see

Appendix I E-653 Proposal 3une 1981). The dev'lces which were wired to the 160 ,

channel amplifier setup at OU had flew faults. 0f 240 stripes examined two had

disconnected wire bonds, and (due to crossover-fanout problems" from the silicon

" disks at 2 x 80 = 160p spacing at 20 rail (1000p) standard P.C. card traces)

. ? pairs were shorted together. Thus 99 percent of the stripes worked.• 4 • ,

" .o • ' ' ."

•_lt fiefs - ". . .

• In setting up at "_'test beam in short order in _d-.May, some amplifier

channels failed or were too noisy and it was not possible to fix some o£ them.

:. The SSD's were arranged in five planes on flour quadrants (quadrant flour has two

detectors C1 and. 2) on it). There are 152 stripes (16, 24, 32, 40, and 40 stripes

were on p.lanes I, 2, 3, 4, S respecti_ eiy) off the Y-SSDts connected (with 140

uorking channels) and in addition 8 - l_un pitch x-stripes on a crossed SSD. "

• The standard d:v/atton of _he noise off the amplifiers is less than 0.2fc (femto-

coulombs; l.e._

I •

". C-10 .....

layers Of 1.6 _a brass (Scm x 3cm) spaced by 4.8 mm respectively as shown in

'Fig. la. A trigger was provided by F1 ° S1 • VET----Oto gate 168 channels o£

LRS 2280 ADC's, readout by a"CRO_MCOcomputer on'to 5" diskettes. An event

is displayed in Fig. lb. The VETOhole, SSD's 1-5 and S1 were aligned

(translationally and rota'tionally) with a transit. Some alignment data runs

were made to check it. Some few small adjustments were made. Final adjustmentsQ

•will be made in the final analysis in the software.

Pr.e!iminary Data Analysis

Some 2000 events have been partially analyzed at this time. A scattergram

• o£the hits on SSD plane 4 vs SSD plane 5 is shown in Fig. 2. The enhancement•

on the diagonal from stripes 15 through 27 represents the shadow o£ the

l.O +. 0.I m_ high hole o£ the VETOon planes 4 and 5. The fifteen stripe width

•(13 to 27) is IS x 0.08 = 1.2 _. The narrowness perpendicular to the diagonal

shows that the alignments (translational and rotational) o£ the VETO and planes

4 and $ are all good to 1 stripe width (80_) over their 10 Cto 12) mm lengths:

A scan £or (interaction) event candidates (2 oF more tracks pointing to the

target with at least 5 points each) was mde. These tracks were fitted and a '

vertex found (XV and ZV}; an example was shown above in Fig. lb. Plots of XV

and ZV should show the height of the hole in the veto counter and the position of

the brass target pieces respectively. The resolution DXV is better than 0.02 nun.

The resolution DZV depends inversely on the opening angle of the tracks as well

as on how far upstream the event occurred (the average opening angles get smaller

_or interactions occurring farther upstream). Please remember that the maximum

" Opening angle is very small (averaging some 25 milli_adians (,less than 2 degreesI)).

• The distributions in XV and ZV are shown in Pig _. 3a and 3b. We see the VETO

hole (Pig. 3a) and the downstream brass pieces (Fig. 35] clearly. The upstream

brass pieces are not resolved ez_ (horizontal bars in Fig. 3b represent the

&ver_ge DZV at the ZV). With greater statistics in the final analysis o£ the

• total sample, we can cut on the larger opening angles (smaller DZV's] and see all

the brass pieces. The slopes o£ the edges of the XV and ZV peaks will give an

experimental measure of the resolution to compare to the (theoretical) calculated

values (such as those printed out in Fig. lb]'. At this level o£ statistics such

agreement appears to exist. -.

Q

4, ° •' e

,

4' " C'12 . ' ' * '

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• AGAle WITH ANOTHEAFILE ' '

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SCATTERGRAH• PLANE 2 )

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ts " " _ " .'t " . "'• tg 1 . . '.. "1.'1. z"11`8 " \..1 1 1.1 ,"1 :121 .:'1 .1 .1. 1 . '_,t 2:2. '2 1 "1 '22 . '1 .'. --1.0 1 ' .. " " " '23 .'1"8 1 71 .

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,,....,, ,, ,,• " 28 3 • . .1 .1 " I '7-.1 12g .'Z 4 .... • '1. '1 ,;L, a _'! _ "_. '3`8 - 3" " ,. _,_ 1 ._.1 '31 . _ _.1. " ' :1'--1"3Z . ,1 J I "1 133 3 "" "1 • I ..l "%._ .,2 4 1 1 '64 1' 1 " 'l Cl. :1 _' Z 1.1.'1 "

" $516 . ..2 " . " '1 • 1 '-,,,. 14

17 "? 1 "1 .'1 " I" 1 . "1 .I ",; 1. Z •18" • ,1 .Z 1 ' " 3" I' .'l "I 1:'1.39" • "1 1 2 -1'2 '1 I I '1 "'2S/_ t HIT EVENTS-PLANE 4 ' "%,, .

39 554 312 356 119 39 472 ?8 1259 .1`824 "',• ".69 ":39 2838 3694 822 1598 .1923 436 3484 ' 1952 ""-.

Z'.13 629 429 159 2933 1878 1848 646 624 575 '• &68 695 556 744 155 "" 480' 7,83 358 547 `8

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• . !It 668 21911 3818 .|576 3114 1691 1384 2811 157' ' e , l

e

FIGURII2 •• ..m,

D-I

: , APPENDIX D

LETrER OFXNTENT

JanuaryZZ,198Zi t

We intend to propose an experiment for LL _ which has unique features for IdentifTln8photons, electrons and muons with momentum resolution of = I% at 50 GeV/c. Hadzon energy

flow will be measuMd. Vertices of particles will be obtained with a precision vertex chamber.

PARZICXPAIING IN_NS AND CONTACT FSI_)NS**

University of Lund, Sweden Guy yon Dardel

: Untverstt7 of Sie|tn, Germany Albert IL Walenta

Max Planck Institute, Germany s Eckart Lorenz

N.LK.H.LF., The NetheHands Plete_ Duinke_

LT.IL, Zurich, Svitserland Hans Hofw

University of Geneva, Switzerland Ronald Mwmod

Untverstt_ o! Lausanne, Sudtserland Raymond Weill

• . L.A.P.P. Anaecy, France Lm_ Massoanet

- Laboratori Nuionall di Frucafl

and Univmtty of Florence, Italy _Ptero Spillanttni

Junta de Enersia Nuclear, Madrid, Spain Juan Antonio Ruble

Institute of High Enersy Physics, BeiJing, China Hsiao-wei Tang

University of Science and Technology, Hofei, China Tzu--tmmf Hsu

University of Hawaii, Honolulu Robert Conce

California Institute of Technology, Pasadena Harvey Newman

University of Oklahoma, Norman George Kalbfleisch

Ohio State University, Columbus William Reay

Carnegie-MeUon University, Pittsburgh Arnold Ensler

PHnceton University, Princeton PteJn.e Piroue

Yale University, New Haven Michael ZeUa_

Harvard University, Cambridge Karl S_auch

Massachusetts Institute of Technolo_, Cambridge Ulrich Becket

ePending Institute approval.**November 1982: Additional institutions have Joined since January 1982.

t

D-2 PAGE 1i + i +

INTRODUCTIDN

Our present understanding of elementary particles is based on two principles, gauge lnvariance

and symmetry breaking. GauSs invariance is wen understood and has been explored by experiments

witness the successes of QED, QCDt and the standard electroweak theory. LEP will significantly

improve out knowledge in this direction. The meaning and the rules of symmetry breaking remain at

mystery. Symmetry bresklng is supposed to generate the tomes of all particles, including neutrinos.

The same phenomenon underlies CP violation, P violation, the 8eneration of weak mixing aneles, the

renormalisability and predictive power of gatqje theories, etc. The cornerstone of symmetry breaking

is the predlctim of the existence of new scalar particles. There m_y be Just one (the mgfrs particle

Ho) or many (the chareed and neutrel tightly bound pseud_calam of teclmicolo_ models). Contrery to"8augeland", "lcalorlaDd" remains essentially unezplored. Vast theoretical efforts of the past two

decades have not led to any scheme bearing the eppealin8 uniqueness of truth. Experiment, so fer, has

only given sn indirect clues the ratio of charged to neutral weak current amplitudes. It is clear that

one of the 8reatest hopes for LEP lies in the exploration of "scalarlend'. This requi_es detectors able

to do precise measurements of clean channels with mall brmschin 8 ratios. Detectors built with these

dem andinj characteristics in mind may also be the beat s_dted to des/with surprising results.DESIGN CONSIDlm_T/ON8

independently of any theoretical speculations, recent history on major discoveries in particle

physics f_m both p_ton accelerators and e+e" colUdtnf beams wu made with detectors specially +.

derlened to measure very precisely both the lepton and the photon chennel_ This is because the

single photon and/re, leptonic channels provide a clean siemd with a mall background which is easier

to undmtmad and to control The discovery of new families of particles such as J _ e+e" andem

T _ _t+Lt , was pomdble only because the mass resoluttun of detectors reached AM/M

D-3

PAGE Zill. Resolution tests muth Germanate crystals (BGO) conducted with silicon diode

readouts to permit the operation of the crystals in mNjnetic fields. Tests were also made on a

sampling calorimeter consisting of teflon tubes filled with liquid scintillator sandwiched between lead

foils. Tests ca hackon calorimeters with proportional chamber readouts operating in a limited

streamer mode are being carried out.

iv. High precision large area (3 z 6 mz) drift chambers with control of systematic errors to

= 30 ¼. l:_ototypes were built to study the construction, the alignment, the survey problems, and the "

gas amplification typical of this type of chamber operating in a magnetic field. Tests were also done

on cross talk, on the systematic errors and resoluticzs, and on alignment with ionization lasers. About

200 such chambers have been used over the past few years at ISR and PETRA by some o! us. Valuable

experience has been gained in the construction and all_ment of these chambers.

Most of the results of these technical developments have been oe are being published in

• Nuclear Instruments and Method_ and other journals. These results yield sufficient information for us

to design a first generation LEP detector.

PROPOSIm DrflCCTOR

We propose to builds

- a large volume low field solenoid mqnet

- a small central tracking detector with very high track resolution

• - a high resolution e.m. calorimeter encapmdatiug the central detector

- a hackon calorimeter acting also as sue= filter

- high precision muon tracking chambm

- a tagging device for 2 photon processes acting also as a precision luminosity monitor

The detector is basically arranged in a cylindric geometry (octagonal shape} with fiat endcaps

as displayed in Fig.1.

We present a description of the components and describe brieily tests and alternative solutions

under study. .

A. Magnet _. Conventional raN|nets _e economically Limited to fields of about 0.S T, and

must be large to obtain good resolution. The total BL2 is 16 T. m 2, resulting in a BL2=7.2 T" m 2 for

the muon spectrometer. The absence of cryogenics, the simple construction (without nested pressure

vessels, heat shields, thin sWuts, etc.}, and the stut_iy, modifiable mechanical construction will allow

quick servicing of the experiment. Furthermore, a conventional magnet can be turned on and off

quickly. Fig. 2 summarizes further parameters of the magnet.

L Co___ We choose high cu_ent to minimize the number of Joints that will have to be made.

Exactly how the coil would be joined (by bolting, riveting, or welding) would depend mainly on the

time schedule and ventilation of the experimental area. The main enKineering problem will be to

reduce the fabrication and assembly cost. Fi_ 2 shows a coil design out of rectangular slabs.

li. Magnet Steel One could use truncated iron pyramids, cemented or tack welded together.

Construction would be like a building but with more iron and less concrete. One could also build the '

magnet out of rough--cut plate as shown in Fig. 2. Fig. 3 shows the assembly sequence. Such a

magnet can be constructed economically.

B. Vertex , Detector. It is well knowl that a minimum ionizing particle leaves along its track a

number of well separated ionization clusters, Just Like the individual bubbles in a bubble chamber.

The best position measurement of the charged particle is achieved when the position of all clusters is

determined. This is the principle of operation of the proposed time expansion chamber, ha a normal

D-4 PAGE 3

,. d3r,i_t chamber the sisxtal is _rmined by the arz4val of the fhrst ,on from several clusters left

by the incoming particle. The proposed time expansion chamber measures the coordinates of

individual clusters in the following ways

I) The drift field is separated from the gas ampUflcatlou region by a fine 8rid (see Fig.4a) and

the drift velocity is adjusted low enough (S IJ/ns) so that the anode signal can follow the duster

structure of the ionization {see Fig.4b).

Z) The dHfarence signal from two pick-up wires close to the anode wire 8ires the oeIKinale

coordinate of the cluster (see Fig.4c). Fig,4 shows a track making an angle 0 with respect to y to

Ulustrate the principle.

i. Layout. The detector is subdivided in to two concentric parts (Fig. 58vb)! the inneur one

from rI = 65 mm to rZ = 125 mm having 12 segments and an outer resion from r3 = IS0 mm to

r4 = S00 mm having 24 sesmants. The small dimension of the inner chamber insures that the requ/redmechanical precision can be reached. The main function of the inner chamber is to meam_e

secondary decay vertices. The outer chamber together with the high precision information of the

inner part of the detector 8ives a measurement of the momenta of the charged particles. "Pattern

recognition wires' are interleaved between sets of precision wires and are equipped with charge

divlsioa readout to measure the coordinate along the whre with a resolution of about I_ of the wire

lanztb.

li. Test_ Test measurements have concentrated on investigating the novel features I) and 2)

of the proposed chamber.

Feature I): In a test chamber the width of the anode siKnal from individual clusters produced

by soft X-ray was measured. It was found to be in affreement with the expectations based on

dHfusion data. Signals from two minimum ionizin8 t_acks close tosether are shown in Fig.6a. They

• can be separated if their mutual distance exceeds Ax • Z00 _t as expected from the diffusion data.

Feature Z): The dHference sisnal from two pick-up wires (200 _t away from each side of the

anode) foe a single cluster from X-rays was clipped to Z0 ns FWHM. The amplitude distributions for

ionization produced on three dHferont field lines and arriving under different angles a at the anode

are shown in Fig.6b. An angular resolution of Aa =S°FW_M is achieved, widch is better than needed

for the quoted position resolution.

These tests were made without magnetic field. Tests with a maEnetic field are planned. A

prototype foe a time expansion chamber is under development.

lti. Calibration. A calibration system will be used in which the position of the laser beam will be

stabilized with a precision of = 5 W. The beam can be displaced by movable reflectors controlled by alaser inte_ferometer.

iv. An Im1_oetant Imp_vement. Recently there has been rapid development of solid state

detectors. We present here as an improvement a solid state vertex detector (Fig. 7) to replace the

inner time expansion chamber. This vertex detector is based on the use of high spatial resolutions

microstrip devices. These devices will resolve 10 IJ rms., will separate particles more than Z.S mr

apart without rlSht-left ambiguities, and give two-dimensional coordinate readout at points radialJy

separated by a fraction of a millimeter.

The detector is ootasonal in shape with four double-s/ded readout planes per side, the inner

6 cm and the outer 11 cm from the beam. Slots are opened every 90 ° to permit extraction of leads

foe those strips runn/n 8 1_ansvewse to the beam. The construction details of a micros1_rip detector, in

D-5 PAGE 4

a beams-eye view, appea_Wig. 7. The stzlps are spaced at and using charge di_ision_'only every fifth strip need be sampled. Spatial resolution will be comparable to that obtained in

reading out every strip, provided amplifier noise is kept below 0.2 femtocoulombs rms. Fewer than

6_ of the tracks will have multiple Mlts in any IS0 M region. On-board multiplexing will reduce

external connections to about 1000 channels.

The solid state material will convert L2% of all T 's, or about 1/4 7 per event. The transverse

resolution per view at the vertex Klven by the solid state detectors is "

Ax = _ ( _ )2 + (15)21 1/2 microns (p in GeV/c)where the first contribution comes from multiple scattering and the second from intrinsic resolution.

The estimated contributiou to A x due to errors in momentum determination is less than 5 M. Usin 8 a

2 GeV/c track as typifying charm decays, we obtain Ax =43 1_ in each view. The error in decay

lensth for the typical charm decay would be roughly 80 IA. By using a 2a cut separating production

and decay vertices, and by demanding that the sum of decay charged-particle momenta be cc_dste_st

with a parent particle m'igdnating near the production vertex, we expect to resolve more than 1/3 of

all charm decays.

The detector also will enhance T lepton identification by providing a 2a me_ment in each

view for the typically 30 _i lepton impact parameter.

Present detectors _e unaffected by 1013 minimum-ionizing parttcles/cm 2, though receipt of

an equivalent number of heavily ionizing particles would be damaging. Below neutron threshold, such

detectors have survived 5 Megarem of X-radiation. P type silicon may increase radiation resistance

by another order of mqnitude.

. Intensive development work is underway and we plan to fit vertices in a Fermilab beam by Fall

1982 using large area devices.

C. CalortmetL zT" The proposed detector entails separate calorimetry for 7, e, and ha-drons.

i.. Elec_oma_etic Calorimeter. Fo_ the energy and position measurements, a high resolution

e.m. calortmete_ of Bismuth Germanate crystahs (BGO) would be the ideal choice because of its

excellent optical properties, high density, and insensitivity to humidity. This calorimeter consists of

approximately 12000 individual crystals of about 22 Xo pointing towards the interaction region. Thecrystals are arranged in a bsreel configuration with fiat endcaps (Fig. 8). The inner cavity has a

diameter of 100 cm and a length of 100 cm. The outer dimensions of the barrel ere 160 cm diameter

and 160 cm leas. This includes readout, thermal shielding, and support. The total volume of BGO willbe 1300-1400 liters.

We will use a silicon photodiode readout which works in a magnetic field. In order to obtain

information about the energy deposition along the crystal, we will mount an additional photodiode on

one crystal side, which will only see the last 1S Xo. This Is of importance for e/hadron discrimination '

where we will make use of both the longitudinal and transverse shower development. For isolated

showers we expect a spatial resolution of approximately o = 2 mm (depending on the energy), 'z,y

resulting in an ansular resolution of _0,4, = 4 mrad. Two neighboring showers can be separated downto a 50 mrad opening angle, thus limiting Y/w° discrimination to

D-6 _ PAGE 5" _p_roximate sdse end uniformit? of _ 1% have sh.eady b_btalned. Furthe.- tests on BGO

will be cazried out at CERN and PETRA. Tests of the readout with standard commerdal lazEe area

silicon photodiodes resulted in a o noise =I.Z MeV and a sensibLUt7 of 850 photoelectrons per MeV

deposited energy.

. iii. Hadron calorimeter. The e,m. calorimete: is surrounded by a conventional hadron calori-

meter extending radially from 80 to Z00 cm (includ|ng support structure}. To provide a satisfactor7

muc_ filter a total of ? nuclear absorption lenr, hs _o are necessary (I _o e.m. calor/meter + 3,_5• Ohad:on calorimeter + ?,.$ _ additional absorber).O

We have chosen a sandwich calorimeter with ?,.$ cm Cu plates 12 mm apert intel_paced with I

cm tube chamber operating in the limited streamer mode (Fig.9). The signals sure branched off the

cathode planes etched in a pattern defining a tower geometry pointing to the interaction region. The

number of towers is not yet finalized but win range between 1000 and 3000 depending on spatial

_ resolution tests. The expected hadronlc ener_r resolution is o/E=TS%/_but might be furtherimproved when weighting the information of the high resolution e,m, calorimeter properly. To fuUy

: absorb hadrons, the calorimeter is backed b7 3 additional coppw plates each IZ cm thick (0.8 _o)interleaved with proportional counters to_ muon tzacking and detection of late developing had:onic

showe_.

•. The globa] eneriD' resolution of the combined calorimetezs is expected to be better than 7% at

the Zo_ thus allowing a very efficient and simple tzdlme: for • .e" =_-tl, tlation events or the detection

• .! of events with subtantial energy carried awa7 by neutrinos.

:: iv. _. The 4: calmdmeter a_angement together with a Z-photon tag&dng device _ g/re

us a very powerftd tool to discriminate between the =nnihilation-induced and two photon-induced

events. A compact tag&dng dev/ce will be made by extending a fine _ BGO calorimeter to angles

very close to the beam axis in a staggered a_angement along a flared beam pipe (First section shown

in Fig. 8). H large diameter superconducting IR quads arre available we plan to tag through the tint

]_ quad as dose as 8 mrad off the initial beam axis. This device a_tows us to tag a substantial

faction of Z _ processes and serves as a luminosity monitor. It also will detect some of the initial

state radiative p,rocesses where T quanta ere emitted dose to the beam dlrectlon. The device wiU betlm

sensitive down to photon energies of approximately 50 MeV with an intrinsic resolution better than

10 MeV and w£11have a spatial resolution of less than I ram. T-dust=7 tests show that BGO loses about

• I0_ of its scintillation efficiency alter X-ray exposu=e of 3 Megarem.

D. Option= a lead-Uq_d S.cintillator Electromagnetic Calorimeter. Shouid the required

amount of BGO not be available in time, a possible alternative is to use a liquid scintillator

calorimeter already developed for a dta_ct photon experiment at CERNI prototype tests were

successful The main advantages of this construction are high spatial resolut.ton, two-photon

. separation power, and low cost.

L La_ The proposed geometry is a bar:el 160 cm long, 100 cm inner diameter, and Z5 cm

, thick. The elements (teflon tubes) axe wound in two sets of helices, alternating rii_ht and left

windtng_, interspaced with sets of elements parallel to the axis to provide a third view (Fig. 10). The

teflon tubes, which extend outside of the fldudal volume as defined by the lead, are then bundled on

either side of the barrel and viewed by a long Light guide (several meters) which brings the Light out

of the magnetic field. This light guide is based on the same design as the calorimeter itself,

consisting of a Liquid with a high refraction index contained in a teflon tube of large diameter

(20-30 ram). One photomuitiplier is attached at the end of each Light guide, with a total of about

D-7 PAGE 6

4000 photom_tipliers and ADC's when both ends are . With this geome_-y, a

circular region of 50 cm radius is left free for the end caps, whose design is still under study.

iL Performance. Test results of the prototype showed that the performances of this design can

be predicted accurately by simulation. It is therefore relatively safe to expect:

a) Energy resolution. Two terms participate: the normal sampling resolution, which is here

about 0.14/,/_, and the residual resolution due to calorimeter inhomogeneity, calibration e__ors, etc.,

which we est/mate to be about ?.$%. The resolution is limited by the spread in the attenuation length

from element to element. Measurements have slow= that this attenuation length is reasonably large

(around 170 cm), With a spread oZ 1% for straight tubes.

b) Spatial resolution. A fit to the shower profile with 1 cm width elements has shown that

the position can be determined to a < 0.8 ram. We expect that with S mm width elements the

accuracy will be better than 0.S ram.

c) Two-shower separation. Fits on 16 GeV/c data with 1 cm width elements have shown

that two photons can be resolved ff their separation is larger than 16 ram. With 5 mm elements, we

expect to resolve two photons distant by more than 10 ram. At a distance of 50 cm, this allows a

positive identification of lr° 's with momenta smaller than 14 GeY/c.

E. Mu..onChambers-

i. Layout. It is presented in Fig. l_b. The design is optimized for 1.25% mass resolution at

I00 GeV dimuon mass. Three stacks of ¢Iadft chambers measure the sagitta of the magnetic bend to

1.8%_ The wires ue 6 m long, supported in the middle, and parallel to the 4.5 kgamm field. To,.improve the resolution each chamber contains matched clusters of N wires.

• The accuracy of the chambers relies on the precise relative positioning of the clustered wires.

This is achieved by pulling all wires over an optically fiat (8 _) glass edge. The glass pieces are

mounted on the aluminum end plates which are precision machined on a computerized lathe. They are

identical foe all chambers and can be precisely checked by overlay. For simplicity of const_tction

and surveying, the chambers are boxes of uniform length. Honeycomb walls keep multiple scattering

small Thin layers of superinsulation provide thermal shielding.

Fig. 11 gives details of the "cluster chamber." Electrostatic and mechanical details are

derived from a 5.4 m long module with 9 wires operating in magnetic field, and from a 96-wire

chamber built by NIKHEF. Both were extensively tested in the last two years in the AGS-BNL 6 GeVproton test beam.

i/. Technic_ Developments , and Test Results: The two essential chamber features are the

performance of long wires with single-ended elec_onic readout in magnetic field and the improve-

memt of the track position as 1/V_. Fig. 12 shows the 5.4 m long test chamber (A) located

horizontally in a solenoid, and in front of it another chamber (B) mounted vertically,

(a) A-Chamber Results: Fig. 13a gives results for a 63:37% mixture of Argon: Ethane at "

atmospheric pressm.e. At B = 0 with l.Z KV/cm drHt field we measttre a saturated drift velocity of

§.I cm/tl s. At B = 0.5 T the electrons drift under the influence of the Lorentz force with an angle at "

towards the wires. The diagram of displacement x versus delay (Fig. 13a) yields the projected driftvelocity from which we determine ct = 18°.

Comparing the results of the resolution measurements shows that each individual wire provides

a position resolution o = 180 ,. This is obtained by comparing a given wire information with the

fitted information from the other $ wires. Contributions from knock on elecl_ons (tail of Landau

distribution) can be seen in Fig. 13b. Applyin 8 a loose cut equivalent to the lines in Fig. 13b excludes

I D-8 th_ PAGE 7" _bss than 10% of the tndivi wire measurements and improves resolution to O= 130 (180) tl for

drift distances of 0.6 (S.0) cm respectively.

(b) B-Chamber Resuits: Measurements in the BNL test beam are shown in Fig. 13c. The

paraliel tracks were analyzed in the following manner: A straight line wu fitted through the first

and last Z5 points in the chamber; 36 wires in the center of the chamber were used to study the

deviation _ obs and the resolution a with respect to the straight Line fit; average points were

calcu/•ted from groups of 1, 4, 9, 16, ZS, and 36 wires;, the distance _obs was determined for theaverage points of the groups chosen with respect to the straight Line. We show in Fig. 13c the

accuracy oread (O2ob s = O2real + O2Line) u a function of the number of measuring wires for tracksparallel to the sense wires. The observed II v_ law agnes with Glueckstern's formula. For 36 wiz_s,

accuracies of ZS tt azl reached ; Since no cuts were aFpl/ed these values are very conservative.

Lii. Alignment: UV laser beams can simulate straight (p = m) tracks in drift chambers operating

• .: in a magnetic field. Fig. Ib shows a provision for linking atl chamber layers with small gas tubes

without windows to enable precise relative alignment with survey optical instruments and ionizing

i Lusts. Fig. 14a) shows the profile of a high intensity N2 laser beam as recorded by one wire. In thismeasurement , the bum was at S0 mm pars/lel to the 96 sense wires. The centroid of the

" distribution can be determined to < 15 ¼, which is more than sufficient. Fig. 14b) shows a schematic- r

of • chambe comparable in size to those of Fig. I. At each of the 4 corners and the two edges of the

i. middle support, a Charge Coupled D...evice with ZS6 cells of 13 x 13 ¼2 size detects relative motion• o

• against a stress-free reference system carrying focused light sources. The digdts/ information is

_. insensitive to temperature, pressure, etc., and is recorded on disk calibration files. After extended

running, motor drive= wedges operating in fields up to 0.S T may execute a computer controlled

compensation. The top graph of Fig. 14c} shows the long term warping of the frame from the

complicated stress tensor. As seen on the bottom graph the compensation confines all deviations to

.. less than 13 ¼, keeping the system reproducible over long periods of time.

iv. Gases: Extensive studies of gas mixtures have been carried out in magnetic field and the

results appear in Fig. 1S.

In summary, these tests have shown:

a) Long wires are stable and work with good resolution o = 200 IAat B =0.S T. Thereforeu.

250 _ is a reasonable value for a system.

. b) The I/,f'_rule works down to 2S tt.

c) Long term mechanical reproducibility is demonstrated. Catlbration by ionizing laser iswithin reach.

F. Experimental Area. An experimental hail able to accomodate the proposed magnet should

differ from the standard defined at the Villers meeting by having its ma/n axis parallel to the beam

and providing wide access to at least cue, and prefeably both, end caps. This could for example be

. achieved by rotating one of the hafts.

The insta£1ation of the magnet, or for that matter its dismantling, will require many months,

but we plan a modular structure permitting quick instailaticu and removal of inside components. It

must be noted that the proposed magnet could accomodate almost any alternate detector and the

latter could replace ours in a matte of weeks.4. -

G. Data Analysis. Many members of our collaboration have been engaged in • • physics

experiments (MARK J, Crystal Ball, LENA, CUSP) using calorimetric techniques (photons, electrons,

D-9 _ PAGE 8

hadrons). Others have beq_engaged in studying lepton pair a_charm production with protonaccelerators and storage rings. This experience will be used to develop our existing software into on-

line and off-fine programs for the proposed detector. We estimate that 3 existing VAX computers in

combination with dedicated microprocessors, together with the large computer centers in our home

institutions, will be used for our initial program. The requdrements for CERN computer time and

computer-finks will be submitted at a later date.

H. Costs and Resources. Table I summarizes the estimated cost of the detector and our .i i

resource requests.

L .p..artlcipation. This coUaboration is (and will be) interested in discussion with other

institutions about participat/on.

UNIQUE FEATURES OF THE DETECTOR

This detector is optimised for measm_g photons and leptomk It is ideal to search for rare

decays involving leptons and to do gamma ray spectroscopy down to 50 MeV. Specifically it has the

following unique features_

,%. The Vertex Chamber. The vertex chamber will have a 30 ¼ resolution. One obtains,, _ ,; , J

AP/P =4/9 + 0.5 pZ (%_. The pod double track resolution (=0.Smm), the small volume, and the low

field make the pattern recognition and track reconstruction tasks relatively easier than a high field..

_ large volume solenoid design. Due to the small volume and low field, the curlup momentum is

p = 21 MeV, whereas for a magnet with a r=lS0 cm and B=15 kganss, the critical momentum is worse

by more than an order of magnitude. The vertex chamber will measure the charge of the particles up• 'i

: to 50 GeV/c and allow us to study the more conventional charged hadron spectroscopy.

. B_The Calorimeter. The energy resolution of BGO is A_E=, _ 0.3) %. For hadrons we0.75 ...... _ /'E'+

have _-_E ._ _ . The independent momentum measurement of charged particles in the centraldetector will simplify the calibratims of the e.m. calorimeter and of the hadron calorimeter for at

least 70% of 4w. For B < .8 particle identification is possible by measuring the momentum with the

vertex chamber and cLE/dxwith the first section of the BGO.

Electrons are detected above 300 MeV over 98% of 4 w (99.9% with reduced efficiency).

The e/h rejection ratio will be better than 1/1000 below a few GeV due to (i) double energy

measurement, (ii} shower depth samp/b_, and possibly (iii) dE/dx information from current division

readout of the inner detector. At I GeV Ap/p = 3% from vertex chamber including multiple

- scattering and is = 1% from BGO. The dE/dx separation is better than 40. At high energies the e/h

rejection ratio will be better than l/S00 due to (i) longitudinal shower sampling, (ii) transverse

shower sampling and (iii) hadron calorimeter veto.

The compact central detector system allows efficient shielding against beam-gas interactions

or synchrotron radiation. It will also be possible to position the IR-quads as close as £220(170) cm to

the interaction point. With large diameter superconducting quads one is able to tag as close as •

8 mrad off the initial beam axis. The tagging device will allow us to further purify annihilation

events from the much more abundant Zy events and tag a substantial fraction of radiative processes. •

C. Muon Chamb..ers. Muens above 1.8 GeV are measured over 75% of 4_. The detector has a

small decay volume. The vertex chamber is able to detect very small decay kinks. The calorimeter

acts as a muon filter. For muon momenta of 1.8-10 GeV, the detector has redundant information due

to double momentum measurement in the central and outside tracking chambers. The background

from decay and punch through is estimated to be = 10"3.

For the calculation of momentum resolution we assume a chamber resolution of ZS0 Wper plane and

D-10 PAGE 9

.. that each chamber will on_ average have two bad measu_em, due to 6-rays, background, or

degraded resolution due to distorted electric field. The 16-Z4--16 sampling measurements in the

bending plane are therefore taken to give 14-ZZ-14 good measurements. Using He bags between the

muon chambers, we obt•in the following muon resolutdon:

s Am1.8% •t p z 50 GeV or--_z L3% (improving to 1.1% if u'= 200 _t) for m = 100 GeV.P

D. Resolution. The good energy resolution on photons and leptons enables us to measure theme.

true width of a narrow resonance (tt, Z°) to obtain • superior sigrnd to background ratio. This is

particularly important because the radiative effects distort the upper part of the Z° spectrum by

about a factor of ten. Precise me•statements on final state particles will greatly enhance the

sensitivity of new particles searches and increase the accuracy of Z ° mass, width and charge

asymmetry measurements. The good resolution on leptons will enable us to identify events of the type

e+e "_"Z°+T on an event by event basis by measuring Z°_ £+2," Without accurate final state particle

measurements, radiative corrections can be used but will not improve the signal to continuum ratio.

F. Flexibility.. The modularity and the compactness of the central detector will allow us to

modify it quickly for unexpected requdrements and will permit us to test substantial puts of the

equipment before the start of LEP.

PHYSICS

:. As noted before, in the past major discoveries at particles •cceleraton were totally

• unpredtcted •t the time of their construction, and furthermore some of the present questions may be

resolved in the next few years. Therefore we list only • few examples to identify the unique features• .:

of our detector.•

A. Sintle lepto n states= Inclusive lepton spectra may yield information on new flavors, new

leptons, supersymmetrlc partners of elecwons, muou, and taus, excited leptons ¼=_' ¼ + T and

_ • s ,-e +T, and lonK-ltved lepton8. In Fig. 16 we show an example of our ability to detect naked

flavor from Z°4" t_ at Z0 < Mt < 45 GeV. The difference between the zero-crossing points of the ¼ _Iand

charge asymmetry values is a direct meamlrement of sin2ew, free from corrections such asradiative effects.

B. SinRle photonsc The richness of inclusive photon study at resonance has been very

impressively demonstrated by the Crystal Ball detector. We can use similar techniques here at the

mass of Z° cr of • new onium stat(_ for example by looking for the monochromatic photons from

i) ZoO' Ho . T, which is suppressed in standard model with BR = Z.4 x 10-0 corresponding to

Z4 monochromatic high energy photon events for 107 Z° produced. The main background is themm

continuous spectrum from Z°_" QOT where the photons tend to be close to the direction of one of the

O's.

ti) Topontum t_ _' HOT, which has • branching ratio = 1% for MHO < 0.9 Mt_. The backgroundagain is the continuous spectrum from t_ _'Y a and is of magnitude similar to the signal beforekinematic outs.

In either case the signal to background ratio is proportional to the energy and spatial resolution of the

photon. With AF..y/Ey < 1% and spatial resolution of 2 ram, we estimate the background to be less

than 50% of the Z° _. Ho + Y and neglisible for the case of t_ "_Ho + Y f_ MHo < 0.9 Mt_. Thus theproposed detector has a chance of discovering such particles in these channels.

(iii) Neutrino counting through reaction e+e" * Z°+ T'_ if LEP tuns slightly higher than the

Z° peak.

(iv) Study the bound and open t_ states with Y spectroscopy.

D-If PAGE 10

c. ....(i) Precise measurements of e+e" and ¼+ "I_ final states around the Z ° resonance determine

its mass, width, and charge asymmetry parameters (Fig. 17).

(ii) The precise measurement of the width gives information on the number of neutrinos. With

10 S events and A M/M 8 1%, we expect A r = 40 MeV, which is to be compared with the v partial

width of _vo _ 180 MeV for each flavor.(ili) Precise measurement of onia leptontc decay.

D. Multilepton states: An unorthodox theory of Gelminl-RoncadelLi predicts the existence of

a family of particles T++, T., and T° which decays into _ I_, IJT, or Tr predominantly. For example,T++we have Z° _ + T'"

4. 4.

For M T • Z0 GeV, we determineM T to an accuracyof 160 MeV.

When some of the muons are replacedby taua,the signatureisthen leptonstogetherwith low

bad, ms multiplicity and large missing ener_ (see Fig.X8).

E. Dile_ton and hadron Jets. Our detector can meum, e leptons and Jets accurately. An

interesting example is the search for Higgs via e+e" _, H° + Z°e•,./,+/,'.

,. Fig. 19 gives the missing mass resolution and rates.

F. Lifetim e of lon_lived particles. The average decay lengths, resolutions, and the distribu-

_. at,us of the vertex distance from the interaction point fer various particles a_e shown in

: Fig. 20. As seen, we can measure lifetimes in the range 10"13 to 10"10sec.

OPT/ONS

"_ A. Superconducting mini-a can be installed at Z.2 m from the interaction point and with minor

modifications to the detector they can be placed at L7 m. It is interesting to note that an

uymmetrica/mini-B arrangement has been successfully applied at CESR.

B. The calorimeter ca= be partly or entirely removed to study individual particles in jets with

high moment