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PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources, Targets and Polarimetry (PTSP 2013) the University of Virginia, Charlottesville, USA, September 2013 Muons, Inc. 1

PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

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Page 1: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

PERSPECTIVES FOR HIGHLY POLARIZED ION

SOURCES DEVELOPMENT

Vadim Dudnikov,

Muons, Inc., Batavia, IL USA

The XVth International Workshop on Polarized Sources, Targets and Polarimetry (PTSP 2013) the University of Virginia, Charlottesville, USA,

September 2013

Muons, Inc.

1

Page 2: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

OUTLINE

Features of an Universal ABP ion source are discussed.

The main innovation of this approach is the strong suppression of parasitic generation of unpolarized H-/D- ions by using novel designs of the dissociator, plasma generator, and surface-plasma ionizer, extraction system, which prevent adsorption and depolarization of particles from the polarized atomic beam. The same system with some modifications can be capable of producing positive and negative ion beams of different species including polarized and unpolarized H-, D-, H+, D+, 3He, and Li.

Production of polarized 3He- ion beam with intensity ~ mA will be discussed

Page 3: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

INTRODUCTION

*High beam polarization degree is essential to the scientific productivity of a collider. *A figure-8 shape of booster and collider rings is an optimized solution to preserve ion beam polarization by avoiding spin resonances during acceleration and to ensure energy independence of spin tune. *In addition, a figure-8 shape ring is the only practical way for accelerating and storing polarized deuterons at a medium energy range. If there is no depolarization during acceleration and storage, the final beam polarization is determined by the initial polarization at extraction from the ion source. * Ion sources with performances exceeding those achieved today is a key requirement for the development of the next generation high-luminosity high-polarization colliders.

Page 4: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Budker Institute of Nuclear Physics www.inp.nsk.su

Novosibirsk State University

www.nsu.ru

Page 5: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Requirements to the polarized source.

Requirements to the polarized source.

• Requirement to ion sources intensity was decreased for many orders by development of charge exchange injection, capable to accumulate beams during tens thousand turns.

• High intensity ~ 5·1011 H-/pulse at 200 MeV after the Linac. At booster beam intensity acceptances are limited by about 1·1011 protons/bunch. The intensity excess can be used to reduce transversal and longitudinal beam emittances by a strong dynamical collimation in the Booster.

• Highest possible polarization is required to reduce a systematical and statistical errors in polarization experiments. Double spin asymmetry statistical error is proportional to ~ 1/sqrt(L P4), therefore a 5% polarization increase in the source (or 5% polarization losses decrease in booster and EIC is effectively equivalent to 30% increase in the data taking time.

• Beam intensity and polarization must be equal at spin-reversal and from pulse to pulse.

ΔI/I <10-3 and ΔP/P < 1% need be reached.

Page 6: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

6

Major Components of MEIC Ion Complex

The MEIC ion beam polarization design requirements are:

• High polarization (over 70%) for protons or light ions (d, 3He++, and possibly 6Li+++).

• Both longitudinal and transverse polarization at all IPs.• Sufficiently large lifetime to maintain high beam polarization.

• Spin flipping at a high frequency.

to high-energycollider ring

Ionsource

SRF linacPrebooster

(accumulator ring)

Large booster Medium-energy collider ring

Cooling Cooling

V. Morozov Report

Page 7: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Existing Sources ParametersUniversal Atomic Beam Polarized Sources (most promising, less

expensive for repeating):• IUCF/INR CIPIOS: Pulse Width Up to 0.5 ms (Shutdown 8/02); Peak Intensity H-/D- 2.0 mA/2.2 mA; Max Pz/Pzz 85% to 95%;

Emittance (90%) 1.2 π·mm·mrad.• INR Moscow: Pulse Width > 0.1 ms (Test Bed since 1984); Peak Intensity H+/H- 11 mA/4 mA; Max Pz 80%/95%; Emittance (90)% 1.0 π·mm·mrad/ 1.8 π·mm·mrad; Unpolarized H-/D- 150/60 mA• SPI Dubna up to 10 mA for D+ ( H+) [under

commissioning]The D+ polarization will be up to 90% of the maximal

vector (±1) &tensor (+1,-2) polarization

OPPIS/BNL: H- only; Pulse Width 0.5 ms (in operation); Peak Intensity >1.6 mA; Max Pz 85% of nominal Emittance (90%) 2.0 π·mm·mrad.

Muons, Inc.

Page 8: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

First polarized-proton sources described at theINTERNATIONAL SYMPOSIUM ON POLARIZATION

PHENOMENA OF NUCLEONSBasel, July 1960

Sources of Polarized Ions a review of early work

SOURCES OF POLARIZED IONSBY W. HAEBERLI

ANNUAL REVIEW OF NUCLEAR SCIENCE Vol. 17, 1967

The status 40 years ago:

W. Haeberli, PSTP-2007, BNL, USA

Page 9: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Method based on 1968 proposal (NIM 62 p. 335)

= 22x10-16cm2 at 2keV -> 100x10-16cm2 at 10eV

A.S. Belov et al. (INR-Moscow) - 20 yrs development workIntense beam of unpolarized D- fromdeuterium surface-plasma ionizes an atomic Beam (2x1017 H0sec puled)

Pulsed 4 mA H-95% PolarizationBELOV

W. Haeberli, PSTP-2007, BNL, USA

Page 10: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Zelenski

OPPIS: Zelenski, Mori et al. 20 years of development

1.6 mA H-85-90% Polarization with new proton source 20-50mA possible

L.W. Anderson (Wisconsin) - optically pumped Na as donor (1979)

3 keV H+ POLARIZEDH+ AND H-

DONOR:

OPTICALLY PUMPEDCHARGE

EXCHANGE

B B

“SONA”TRANSITION

W. Haeberli, PSTP-2007, BNL, USA

Page 11: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

A. Belov & V. Derenchuk: IUCF/INR CIPIOS developers

Page 12: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

ABPIS with Resonant Charge Exchange Ionization and Surface-Plasma D- generation

Muons, Inc.

• INR Moscow• H0↑+ D+ ⇒H+↑+ D0

• D0↑+ H+ ⇒D+↑+ H0

• σ~ 5 10-15cm2

• H0↑+ D−⇒H−↑+ D0

• D0↑+ H−⇒D−↑+ H0

• σ~ 10-14cm2

A. Belov, DSPIN2009

Page 13: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Main Systems of INR ABPIS with Resonant Charge Exchange Ionization

Muons, Inc.

Page 14: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Atomic Beam Polarized Ion source

In the ABS, hydrogen or deuterium atoms are formed by dissociation of molecular gas, typically in a RF discharge. The atomic flux is cooled to a temperature 30K - 80K by passing through a cryogenically cooled nozzle. The atoms escape from the nozzle orifice into a vacuum and are collimated to form a beam. The beam passes through a region with inhomogeneous magnetic field created by sextupole magnets where atoms with electron spin up are focused and atoms with electron spin down are defocused.Nuclear polarization of the beam is increased by inducing transitions between the spin states of the atoms. The transition units are also used for a fast reversal of nuclear spin direction without change of the atomic beam intensity and divergence. Several schemes of sextupole magnets and RF transition units are used in the hydrogen or deuterium ABS. For atomic hydrogen, a typical scheme consists of two sextupole magnets followed by weak field and strong field RF transition units. In this case, the theoretical proton polarization will reach Pz = _1. Switching between these two states is performed by switching between operation of the weak field and the strong field RF transition units. For atomic deuterium, two sextupole magnets and three RF transitions are used in order to get deuterons with vector polarization of Pz = _1 and tensor polarization of Pzz= +1, -2Different methods for ionizing polarized atoms and their conversion into negative ions were developed in many laboratories. The techniques depended on the type of accelerator where the source is used and the required characteristics of the polarized ion beam (see ref. [2] for a review of current sources).For the pulsed atomic beam-type polarized ion source (ABPIS) the most efficient method was developed at INR, Moscow [3-5]. Polarized hydrogen atoms with thermal energy are injected into a deuterium plasma where polarized protons or negative hydrogen ions are formed due to the quasi-resonant charge-exchange reaction:

Page 15: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Ionization of polarized atoms

Resonant charge-exchange reaction is charge exchange between atom and ion of the same atom: A0 + A+ →A + + A0

•cross -section is of order of 10-14 cm2 at low collision energy

•Charge-exchange between polarized atoms and ions of isotope relative the polarized atoms to reduce unpolarized background

•W. Haeberli proposed in 1968 an ionizer with colliding beams of ~1-2 keV D- ions and thermal polarized hydrogen atoms:

H0↑+ D−⇒H−↑+ D0

Page 16: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Destruction of negative hydrogen ions in plasma

• H + e H0 + 2e ~ 410-15 cm2

• H + D+ H0 + D0 ~ 210-14 cm2

• H + D0 H0 + D ~ 10-14 cm2

• H + D2 H0 + D2 + e ~ 210-16 cm2

• H + D0 HD0 + e ~ 10-15 cm2

Page 17: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Details of ABIS with Resonant Charge Exchange Ionization

Page 18: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Resonance charge exchange ionizer with two steps surface plasma

converter*Jet of plasma is guided by magnetic field to internal surface of cone;

*fast atoms bombard a cylindrical surface of surface plasma converter initiating a secondary emission of negative ions increased by cesium adsorption.

*An electron blocker collects plasma electrons, decreases electron extraction and H-destruction

Page 19: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

INR ABPIS: Oscilloscope Track of Polarized H- ion

Polarized H- ion Current 4 mA (vertical scale-1mA/div) Unpolarized D- ion current 60 mA (10mA/div)Parasitic H- current without polarized H atomic beam

A. Belov

Page 20: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Probability of H- emission as function of work function (cesiation effect)

The surface work function decreases with deposition of particles with low ionization potential and the probability of secondary negative ion emission increases greatly from the surface bombarded by plasma particles.

Dependence of work function on surface cesium concentration for W crystalline surfaces and relative yield Y of H- secondary emission for W surface index (111), right scale

Muons, Inc.

20

Page 21: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Schematic of negative ion formation on the surface (φ>S)

(formation of secondary ion emission; Michail Kishinevsky)

Sov. Phys. Tech. Phys, 45 (1975)) •Affinity lever S is lowering by image forces below Fermi level during particle approaching to the surface;

• Electron tunneling to the affinity level;

• During particle moving out of surface electron affinity level S go up and the electron will tunneling back to the Fermi level;

• Back tunneling probability w is high at slow moving (thermal) and can be low for fast moving particles; Ionization coefficient β- can be high ~0.5 for fast particles with S<~ φ

Page 22: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Coefficient of negative ionization as function of work function and particle speed

Kishinevskiĭ M E, [Sov. Phys. Tech. Phys., 48 (1978), 773; 23 (1978), 456

Page 23: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Production of surfaces with low work function (cesium coverage)

The surface work function decreases with deposition of particles with low ionization potential (CS) and the probability of secondary negative ion emission increases greatly from the surface bombarded by plasma particles.

Muons, Inc.

23

Dependences of desorption energy H on surface Cesium concentration N for different W crystalline surfaces: 1-(001); 2-(110); 3-(111); 4-(112).

The work function in the case of cesium adsorption in dependence upon the ratio of sample temperature T to cesium-tank temperature TCs for collectors of 1) a molyb denum polycrystalline with a tungsten layer on the surface, 2) (110) molybdenum, 3) a molyb denum polycrystalline, and 4) an LaB6 polycrystalline.

Page 24: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Probability of particles and energy reflection for low energy H particles

Page 25: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Influention of Cs+H co-adsorption to H-/D- reflection

*Conversion Ho/H- by Scattering on W+Cs+H surface *Desorption of H- from W+Cs+H surface *Important for suppression of H-/D- production from depolarized components P. W. van Amersfoort, et al., J. Appl. Phys. 59, 241 (1986);

Page 26: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

The low WF is need to support in dense plasma. It is necessary to inject some Cs (as shown in SNS SPS)

H- beam intensity is raised after casiation but decayed exponencialli during operation

Page 27: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Fortunately, condition of “activation” was found in SNS SPS for efficient operation with very low Cs injection (mg/weeks, instead mg/hour) This “gift of nature” is not understudy in full scale an is not reproducible in different SPS. (Need further development)

Page 28: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

At firs it was hypothesed, that a better cleaning of electrodes surface increases the binding energy and decrease Cs evaporation and sputtering.

But it was recognized that a converter surface is deposited by dark film. Not only cleaning but deposition are important for optimal cesiation. Clean H plasma!

Page 29: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Distributions of elements on the converter cone surface. Sputter time in minutes. 20 min of sputtering is ~20 nanometers

Carbon deposition and Cs intercolation can be important for stable SPS operation with low Cs consumption

Page 30: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Schematic diagram of IUCF ABPIS with resonant charge exchange ionization

(was tested for long time injection of D-)

Page 31: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

The pulsed polarized negative ion source (CIPIOS) multi-milliampere beams for injection into the Cooler Injector Synchrotron (CIS). Schematic of ion source and LEBT showing the entrance to the RFQ.

The beam is extracted from the ionizer toward the ABS and is then deflected downward with a magnetic bend and towards the RFQ with an electrostatic bend. This results in a nearly vertical polarization at the RFQ entrance.

Belov, Derenchuk, PAC 2001

Page 32: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Components of IUCF ABPIS (sextupole, ionization solenoid, RF dissociator, bending magnet, Arc

discharge plasma source,

Page 33: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Schematic of JINR ABPIS (SPI) with resonant charge exchange ionization

(polarized H+,D+)

Page 34: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

General view of JINR ABPIS (SPI) with resonant charge exchange ionization

(polarized H+,D+)

Page 35: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Arc discharge ion source with expansion of plasma jet (Dimov BINP 1962)

Plasma density up to 10 **15 cm-3; Ionization 99.9 %, dissociation 99%, transverse ion temperature 0.005 eV; multi slit extraction (H+, He+ ~2A); H-~16 mA (H2); D-~100 mA (Na); He-~10 mA (Na). 1-gas valve; 2-triggering; 3 cathode; 4-barier washe; 5-woshed channel; 6-anode; 7-extracrion holder; 9, 10 –extraction grids.

Page 36: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Long pulse arc-discharge plasma generator with LaB6 cathode (heating prevents polarized

particles adsorption and desorption as negative ions)

Version with one LaB6 disc Version with several LaB6 discs

Metal-ceramic discharge channel is developed Can be lower gas density, Higher He++ beam current

Page 37: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Fast, compact gas valve, 0.1ms, 0.8 kHz

1 -current feedthrough;2- housing; 3-clamping screw; 4-coil; 5- magnet core; 6-shield; 7-screw;8-copper insert; 9-yoke; 10-rubber washer-returning springs; 11-ferromagnetic plate-armature; 12-viton stop;13-viton seal; 14-sealing ring; 15-aperture; 16-base; 17-nut.

Page 38: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Fast, compact Cesium Supplies

*Cesium oven with cesium chromate pellets (Cs2CrO4+Ti) and press-form for pellets preparation.

• Cesium oven with BiCs2 alloy

• *Cesium oven with Cs getters

• (Cs2ChO4 +Zr+Al+…)

Page 39: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Highly transparent fine precise extraction system

A four-electrode multislit extraction consists ofthree multi-wire grids and a fourth cylindrical grounded electrode. The grids are made of 0.2 mm molybdenum wire. The spacing between wires is 1.0 mm. The wires are positioned on the mounting electrodes by precisely cut grooves and fastened by point welding. The mutual grid alignment accuracy is better than 0.02 mm. The gap between the first and second grids is 1.0 mm, the second and third grids—2.0 mm, the third and fourth—2.0 mm. This design increases the beam brightness relative two grids system.

Page 40: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

BNL Polarimeter, 1.2 10**17 p/s

BNL Polarimeter, 1.2 10**17 p/s

• The H-jet polarimeter includes three major parts: polarized Atomic Beam Source (ABS), scattering chamber, and Breit-Rabi polarimeter.

• The polarimeter axis is vertical and the recoil protons are detected in the horizontal plane.

• The common vacuum system is assembled from nine identical vacuum chambers, which provide nine stages of differential pumping.

• The system building block is a cylindrical vacuum chamber 50 cm in diameter and of 32 cm length with the four 20 cm (8.0”) ID pumping ports.

• 19 TMP , 1000 l/s pumping speed for hydrogen.

Page 41: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Schematic of ABPISSchematic of ABPIS

• The PABIS includes three major parts: polarized Atomic Beam Source (ABS), ionizer, beam formation/separation,and Lemb polarimeter.

• The PABIS axis is vertical and ion beam is bended to the horizontal plane.

• The common vacuum system is assembled from 5 identical vacuum chambers of ABS, which provide 5 stages of differential pumping.

• The system building block is a cylindrical vacuum chamber 50 cm in diameter and of 32 cm length with the four 20 cm (8.0”) ID pumping ports.

• 10 TMP , 1000 l/s pumping speed for hydrogen+ 2.2 kl/s+cryopump

Page 42: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Further ABPIS development

*Intensity and polarization of polarized beams produced by ABPIS can be improved by further optimization of ABS and ionization technique.

*In particular, atomic beam formation should be studied to overcome limitations connected with a beam-skimmer interference.

*Sextupole magnet system parameters should be optimized taking into account results of optimization of atomic beam formation system.

*With these improvements pulsed polarized H-, (D-) ion beams with peak intensity of ~10 mA (~ 20 mA for H+ and D+ ions) and polarization of ~ 95% seems to be possible

Page 43: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

INJECTION OF BACKGROUND GAS AT DIFFERENT POSITION

ATTENUATION OF THE BEAM ISDEPENDENT FROM THE POSITIONOF THE GAS INJECTIOJN

NOT MANY EXPERIMENTAL DATAAVAILABLE

D.K.Toporkov, PSTP-2007, BNL, USA

Fine art of intense atomic beam formation (intensity limitation)

Page 44: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Cryogenic Atomic Beam Source

Liquid nitrogenCryostatCryostat

Two group of magnets – S1, S2 (tapered magnets) and S3, S4, S5 (constant radius) driven independently, 200 and 350 A respectively; Bt~ 4.8 T.

BINP atomic beam source with superconductor sextupoles

Page 45: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Focusing magnets

Permanent magnetsB=1.6 TSuperconductingB=4.8 T

sr rad srrad

Page 46: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Polarized Gas Target, ABS and LDS

Flux of polarized deuterium atoms injected into the cell at/sec. Magnetic poletip field of superconducting magnets up to 4.8 T

Pzz=0.4, target thickness viewed by the detector 8x1013at/cm2

168.2*10

13x14x400 mm

Inner diam. 44 mm

Dmitri Toporkov Summary of the 10th Workshop onSPIN2004 Polarized Sources and Targets PST2003

Yuri Shestakov (BINP) High Density Polarized Deuterium Gas Target for the VEPP-3 Electron Storage Ring

Page 47: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

3He++ Ion source with Polarized 3He Atoms and Resonant Charge

Exchange Ionization

A.S. Belov, PSTP-2007, BNL, USA

Page 48: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Plans of ABPIS development

Review of existing versions of ABPIS components for choosing an optimal combinations;

General design of optimal ABPIS;

Estimation availability of components and materials:

Estimate of project cost and R&D schedule;

Establish cooperaion:

INR, A. Belov

BINP, D. Toporkov, V. Davydenko,

BNL, A. Zelenski,

IUCF, Dubna, V. Derenchuk, V. Fimushkin,

COSY/Julich, R. Gebel.

Page 49: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

3He- sources development

* For alpha particles diagnostics in fusion plasma of ITER under development He- ion source with current ~10 mA and Energy ~1 MeV (He+ current ~3 A with low emittance), Sasao et al..* Autoionization is used for fast Heo production in ground state.Metastable He- have lifetimes ~10 mcs and ~350 mcs.*We start looking for lifetime dependences of hyperfine states for possible using this dependences for polarized 3He- production.* This dependences are exist. And polarized 3He- production is possible.

Page 50: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Polarized 3He- ions production

Polarized 3He- ions production

• Fine and hyperfine structure of 3He- ions

• Different hyperfine components of metastable relative autoionization 3He- negative ions with different orbital and spin projections have different lifetime relative autoionization.

• Components with highest momentum 5/3 have largest lifetime ~350 μsec when components with lower momentum have lifetime ~10 μsec. 3He- ion beam composed only of hyperfine components [5/2, +-5/2> can be produced and then quenching one of the hyperfine levels by an RF resonant field can be produced 3He- beam with polarization ~100%.

(S. Manson, PR A,3, 1,147,1971)

Page 51: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

The decay curve of 4He- measured at 10 K.

The solid curve is a fit to the data. The insert shows a time region in which the decay of the short lived J =1/2 and J=3/2 levels dominate the intensity. (P. Reinhed, et al.,PRL 103, 213002 (2009) )

Temperature dependence of the measured lifetime of the 1s2s2p 4Po5/2 level of 4He-. The effect on the decay rate from photodetachment by blackbody radiation can readily be seen as a decrease in the measured lifetime above 100 K.

Page 52: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Separation of fine components of He- in the magnetic field

Components with highest momentum 5/3 have largest lifetime ~350 μsec when components with lower momentum have lifetime ~10 μsec. 3He- ion beam composed only of hyperfine components [5/2, +-5/2> can be produced and then quenching one of the hyperfine component by an RF resonant field can be produced 3He- beam with ~100% polarization.

The fine-structure results are: 

Δ53= 825.23 + 0.82 MHz,Δ51 = 8663 + 56 MHz.

Page 53: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Separation of fine components of 7 Li* in the magnetic field

Energy as a function of magnetic field for various (1s2s2p) 4P substates of 7Li The positions of the three observed anticrossings are indicated by A.

Production of polarized 7Li through different lifetime of metastable states is also available.(PHYSICAL REVIEW A VOLUME 3, NU MB E R JANUARY 1971, Determination of Energies and Lifetimes of the Metastable Auto-ionizing (1s2s2p) 4P States of 6Li and 7Li by a Zeeman-Quenching Technique, M. Levitt and R. Novick, P. D. Feldman).

Page 54: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

He-/He+ yield and beam intensity vs. He+ energy in K target.

 

With 2 A He+ current from BINP arc discharge source it is possible to have ~ 0.1 A of He- ions. Up to 4 mA of 3He- with high nuclear polarization can be produced.

A. SZANTO DE TOLEDO and 0. SALA, Production of Negative Helium ions, Revista Brasileira de Física, Vol. 7, Nº 1, 1977).

Page 55: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Polarized 3He- ion sourcePolarized 3He- ion source

• BINP High brightness arc discharge ion source with Cs jet charge exchange target (as for BNL OPPIS)

A schematic of the experiment on He- beam production. 1- He+ source, 2 – extraction system, 3 – space charge compensation

Xe, 4 – K (Rb, Cs) target, 5 – bending magnet, 6 – Decay channel with solenoid and RF transition, 7-He+ beam; 8-space

charge compensated beam; 9-He- beam.

Page 56: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Polarized 3He- ion sourcePolarized 3He- ion source

• BINP High brightness arc discharge ion source with Cs jet charge exchange target (as for BNL OPPIS)

A schematic of the polarized 3He- beam production. 1- He+ source, 2 – extraction system, 3 – space charge compensation Xe, 4 – K (Rb, Cs) target, 5 – bending magnet, 6 – Decay channel with solenoid and RF transition, 7-He+ beam; 8-space charge compensated beam; 9-He- beam;

10-Polarized 3He- beam; 11-neutrals of 3He beam.3He- negative ion are separated from 3He neutrals by separating magnets (5). The separated 3He- beam (10) is accelerated for further use and can be converted to 3He++ by stripping in a foil or He gas target. Beam tubes need be cooled below T~150K.

Page 57: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

References have been found

• It was suggested earlier that the differentialmetastability of the (1s2s2p) 4P levels would providea possible mechanism for producing polarized electrons

and nuclei, especially those of 3He (I =1/2, ) and 6Li (I=1).

P. Feldman and R. Novick, in Comptes Rendus du Congres International de Physique Nucleaire, Paris, 1964, edited by P. Gugenberger (CNRS, Paris, 1964), Vol. II, 4a/C144, pp. 785-786.

Muons, Inc.

Page 58: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Polarized 6Li+++ Optionsand other elements with low ionization potential

Existing Technology:• Create a beam of polarized atoms using ABS• Ionize atoms using surface ionization on an 1800 K

Tungsten (Rhenium) foil – singly charged ions of a few 10’s of µA

• Accelerate to 5 keV and transport through a Cs cell to produce negative ions. Results in a few hundred nA’s of negative ions (can be increased significantly in pulsed mode of operation)

• Investigate alternate processes such as quasiresonant charge exchange, EBIS ionizer proposal or ECR ionizer. Should be possible to get 1 mA (?) fully stripped beam with high polarization

• Properties of 6Li: Bc= 8.2 mT, m/mN= 0.82205, I = 1

Bc = critical field m/mN= magnetic moment, I = Nuclear spin

Muons, Inc.

Page 59: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Production of highest polarization and reliable operation are main goals ofthese ion sources development

Development of Universal Atomic Beam Polarized Sources (most promising, less expensive for repeating) .

• It is proposed to develop one universal H-/D-/He ion source design which will synthesize the most advanced developments in the field of polarized ion sources to provide high current, high brightness, ion beams with greater than 90% polarization, good lifetime, high reliability, and good power efficiency. The new source will be an advanced version of an atomic beam polarized ion source (ABPIS) with resonant charge exchange ionization by negative ions, which are generated by surface-plasma interactions.

Muons, Inc.

Page 60: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Realistic Extrapolation for Future

ABS/RX Source: • H- ~ 10 mA, 1.2 π·mm·mrad (90%), Pz > 95%• D- ~ 10 mA, 1.2 π·mm·mrad (90%), Pzz >

95%OPPIS:• H- ~ 40 mA, 2.0 π·mm·mrad (90%), Pz ~ 90%• H+ ~ 40 mA, 2.0 π·mm·mrad (90%), Pz ~ 90% OPPIS intensity can be higher, but Polarization in ABPIS/RX Source can be higher

because ionization of polarized atoms is very selective and molecules do not decrease polarization.

* 3He- ~ 1 mA, Pz>90%

Muons, Inc.

Page 61: PERSPECTIVES FOR HIGHLY POLARIZED ION SOURCES DEVELOPMENT Vadim Dudnikov, Muons, Inc., Batavia, IL USA The XVth International Workshop on Polarized Sources,

Summary

Optimized versions of existing polarized ion sources (ABPIS and OPPIS) and advanced injection methods are capable to delivery ion beam parameters necessary for

Projected high luminosity of EIC.

ABPIS is preferable as universal source

It is possible to start development, design

and fabrication (cost ~1 M$).

Thank You for Your Attention.

Muons, Inc.