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

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

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.

Budker Institute of Nuclear Physics Novosibirsk State University Many components developed in BINP+NSU are used in advanced versions of PIS

Requirements to the polarized source. Requirement of ion sources intensity was decreased for many orders by development of charge exchange injection, capable to accumulate beams during tens thousand turns. High intensity ~ 5·10 11 H - /pulse at 200 MeV after the Linac. At booster beam intensity acceptances are limited by about 1·10 11 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 P 4), 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.

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-energy collider ring Ion source SRF linac Prebooster (accumulator ring) Large booster Medium-energy collider ring Cooling V. Morozov Report

Existing Sources Parameters Universal 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.

First polarized-proton sources described at the INTERNATIONAL SYMPOSIUM ON POLARIZATION PHENOMENA OF NUCLEONS Basel, July 1960 Sources of Polarized Ions a review of early work SOURCES OF POLARIZED IONS BY W. HAEBERLI ANNUAL REVIEW OF NUCLEAR SCIENCE Vol. 17, 1967 The status 40 years ago: W. Haeberli, PSTP-2007, BNL, USA

Method based on 1968 proposal (NIM 62 p. 335)  = 22x cm 2 at 2keV -> 100x cm 2 at 10eV   A.S. Belov et al. (INR-Moscow) - 20 yrs development work Intense beam of unpolarized D - from deuterium surface-plasma ionizes an atomic Beam (2x10 17 H 0  sec pulsed) Pulsed 4 mA H -  95% Polarization BELOV “ W. Haeberli, PSTP-2007, BNL, USA

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 + POLARIZED H + AND H - DONOR: OPTICALLY PUMPED CHARGE EXCHANGE BB “SONA” TRANSITION W. Haeberli, PSTP-2007, BNL, USA

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

ABPIS with Resonant Charge Exchange Ionization and Surface-Plasma D- generation Muons, Inc. INR Moscow H 0 ↑+ D+ ⇒ H+↑+ D 0 D 0 ↑+ H+ ⇒ D+↑+ H 0 σ~ cm 2 H 0 ↑+ D− ⇒ H−↑+ D 0 D 0 ↑+ H− ⇒ D−↑+ H 0 σ~ cm 2 A. Belov, DSPIN2009

Main Systems of INR ABPIS with Resonant Charge Exchange Ionization Muons, Inc.

Ionization of polarized atoms Resonant charge-exchange reaction is charge exchange between atom and ion of the same atom: A 0 + A + →A + + A 0 cross -section is of order of cm 2 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: H 0 ↑+ D − ⇒ H − ↑+ D 0

Details of ABIS with Resonant Charge Exchange Ionization

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

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

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. 18

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

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

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. 21 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 molyb­denum polycrystalline with a tungsten layer on the surface, 2) (110) molybdenum, 3) a molyb­denum polycrystalline, and 4) an LaB6 polycrystalline.

Probability of particles and energy reflection for low energy H particles

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);

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

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)

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!

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

Schematic diagram of IUCF ABPIS with resonant charge exchange ionization (was tested for long time injection of D-)

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

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

Schematic of JINR ABPIS (SPI) with resonant charge exchange ionization (polarized H+,D+)

General view of JINR ABPIS (SPI) with resonant charge exchange ionization (polarized H+,D+)

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 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.

Long pulse arc-discharge plasma generator with LaB 6 cathode (heating prevents polarized particles adsorption and desorption as negative ions) Version with one LaB 6 discVersion with several LaB 6 discs Metal-ceramic discharge channel is developed Can be lower gas density, Higher He++ beam current

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.

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+…)

Highly transparent fine precise extraction system A four-electrode multislit extraction consists of three 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.

BNL Polarimeter, **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.

Schematic 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

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

INJECTION OF BACKGROUND GAS AT DIFFERENT POSITION ATTENUATION OF THE BEAM IS DEPENDENT FROM THE POSITION OF THE GAS INJECTIOJN NOT MANY EXPERIMENTAL DATA AVAILABLE D.K.Toporkov, PSTP-2007, BNL, USA Fine art of intense atomic beam formation (intensity limitation)

Cryogenic Atomic Beam Source Liquid nitrogenCryostat 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

Focusing magnets Permanent magnets B=1.6 T Superconducting B=4.8 T       sr  rad   sr  rad

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 P zz =0.4, target thickness viewed by the detector 8x10 13 at/cm 2 13x14x400 mm Inner diam. 44 mm Dmitri Toporkov Summary of the 10 th Workshop on SPIN2004 Polarized Sources and Targets PST2003 Yuri Shestakov (BINP) High Density Polarized Deuterium Gas Target for the VEPP-3 Electron Storage Ring

3 He ++ Ion source with Polarized 3 He Atoms and Resonant Charge Exchange Ionization A.S. Belov, PSTP-2007, BNL, USA

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.

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 two lifetimes ~10 µs and ~350 µs. *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 1s2s2p 4Po5/2.

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)

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, (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.

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: Δ 53 = MHz, Δ 51 = MHz.

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).

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).

Polarized 3He- ion source BINP High brightness arc discharge ion source with K 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.

Polarized 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.

References have been found It was suggested earlier that the differential metastability of the (1s2s2p) 4P levels would provide a 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 Muons, Inc.

Polarized 6Li+++ Options and 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 µ A 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= , I = 1 Bc = critical field m/mN= magnetic moment, I = Nuclear spin Muons, Inc.

Production of highest polarization and reliable operation are main goals of the proposed 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.

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>70% Muons, Inc.

Summary Optimized versions of discussed 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.

Back up slides Muons, Inc.

G.I. Budker, founder and director of INP

Round table BINP King Arthur Pub Round table of BINP is the method of problems solving

Traditional Siberian folk’s handicrafts in BINP: Electron cooling; Siberian Snakes; Negative ion sources; Neutral Beam Injectors; Superconducting wigglers; Sources of Polarized particles: Industrial accelerators; Storage Rings; Muons colliders……. The electron cooling force in a magnetized electron beam with an anisotropic electron velocity distribution was derived by Derbenev and Skrinsky in 1978 [1]. [1] Ya. S. Derbenev and A. N. Skrinskii, Magnetization effects in electron cooling, Sov. J. Plasma Phys. 4(3), May–June 1978,

HELICAL SIBERIAN SNAKES There are several methods to reduce the depolarizing effect of the resonance field harmonics, but the Siberian snake technique was demonstrated to be most effective in maintaining beam polarization. A snake is a configuration of magnets that, in the orbit frame, rotates the spin by 180 o about an axis which lies in the horizontal plane. This proposal has been made by Y.S.Derbenev and A.N.Kondratenko[1,2]. [1]. Ya.S.Derbenev and A.N.Kondratenko, Proceedings of 10-th International Conference on High Energy Accelerators, Protvino, USSR, [2] Ya.S.Derbenev and A.N.Kondratenko, Proc. Int. Conf. on High Energy Physics with Polarized Beams and Polarized Targets, Argonne, III, (1978), p. 292ff.

Workshop on high –energy spin physics, Protvino, IHEP, September,1983 Confirmation of feasibility of polarization preservation by Siberia snake Workshop on high –energy spin physics, Protvino, IHEP, September,1983 Confirmation of feasibility of polarization preservation by Siberia snake Ya.Derbenev- “Siberian snake”.

EIC Design Goals  Energy Center-of-mass energy between 20 GeV and 90 GeV energy asymmetry of ~ 10,  3 GeV electron on 30 GeV proton/15 GeV/n ion up to 9 GeV electron on 225 GeV proton/100 GeV/n ion  Luminosity up to cm -2 s -1 per interaction point  Ion Species Polarized H, D, 3 He, possibly Li Up to heavy ion A = 208, all striped  Polarization Longitudinal polarization at the IP for both beams Transverse polarization of ions Spin-flip of both beams All polarizations >70% desirable  Positron Beam desirable Muons, Inc. 66 Yuhong Zhang For the ELIC Study Group Jefferson Lab

ELIC (e/A) Design Parameters IonMax Energy (E i,max ) Luminosity / n (7 GeV x E i,max ) Luminosity / n (3 GeV x E i,max /5) (GeV/nucleon)10 34 cm -2 s cm -2 s -1 Proton Deuteron H He He C Ca Pb * Luminosity is given per unclean per IP

Motivation for high polarization We need particle sources with a highest polarization because polarization can be preserved during acceleration by Siberian Snake and by Figure-8 rings. Ion sources for production of polarized negative and positive light and heavy ions will be considered. Atomic bean ion source can be used for generation of polarized H-, H+, D-, D+, He++, Li +++ ions with high polarization and high brightness. References: Belov A.S., Dudnikov V.,et. al., NIM A255, 442 (1987). Belov A.S., Dudnikov V.,et al.,. NIM A333, 256 (1993). Belov A.S, Dudnikov V., et. al., RSI, 67, 1293 (1996). Bel’chenko Yu. I., Dudnikov V., et. al., RSI, 61, 378 (1990) Belov A.S. et. al., NIM, A239, 443 (1985). Belov A.S. et. al., 11 th International Conference on Ion Sources, Caen, France, September 12-16, 2005; A.S. Belov, PSTP- 2007, BNL, USA; A.S. Belov, DSPIN2009, DUBNA, Russia; A. Zelenski, PSTP-2007, BNL, USA; DSPIN2009, DUBNA, Russia source of polarized negative hydrogen ions with a resonant charge-exchange plasma ionizer Author(s): Belov, AS; Esin, SK; Netchaeva, LP; et al: REVIEW OF SCIENTIFIC INSTRUMENTS,: 67 : 3,: , source of polarized negative hydrogen ions with a resonant charge-exchange plasma ionizer Muons, Inc. 68

Cross-section vs collision energy for process H  + H 0  H 0 + H   = cm 2 at ~10eV collision energy

Destruction of negative hydrogen ions in plasma H  + e  H 0 + 2e  ~ 4  cm 2 H  + D +  H 0 + D 0  ~ 2  cm 2 H  + D 0  H 0 + D   ~ cm 2 H  + D 2  H 0 + D 2 + e  ~ 2  cm 2 H  + D 0  HD 0 + e  ~ cm 2

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, -2 Different 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:

BNL OPPIS, A. Zelenski

Enhanced OPPIS with BINP injector

BINP Injector for OPPIS

Cross-section vs collision energy for process He ++ + He 0 →He 0 + He ++ σ=5 ⋅ 10-16cm 2 at ~10eV collision energy A.S. Belov, PSTP-2007, BNL, USA