Performances of frozen-spin polarized HD targets for Nucleon spin - PDF document

Performances of frozen-spin polarized HD targets for Nucleon spin experiments. @ PST05, Nov.14-17, 2005 T. Kageya 1,2 on behalf of LEGS Spin Collaboration 1. Brookhaven National Lab., Upton, NY, USA 2. Virginia Polytechnic Institute and State University, Blacksburg, VA, USA * * Supported by a research grant from the U.S. Department of Energy and the U.S. National Science Foundation

Motivation Motivation Nucleon Spin Sum Rules Gerasimov−Drell−Hearn ∞ ∫ σ σ α - 1 κ 1/2 3/2 2 - = dE γ π 2 2 E 4 2m γ m π Nucleon spin strucure at Q 2 =0 LEGS covers ~65% Measurement down to pion threshold is important Forward Spin−Polarizability ∞ ∫ σ σ - 1 γ 1/2 3/2 = dE γ π 0 2 3 4 E γ m π Test of chiral perturbation theories LEGS covers ~90% Measurement down to pion threshold is important Multipole Amplitudes Double polarization observables Asymmetries E and G Neutron channels π o n and π − p

Attractive Features Polarized HD Target 1. Pure Solid Targets * Only unpolarizable nucleons associated with target cell which can be measured separately and subtracted in coventional way 2. Long Spin-Relaxation time ~ 1 year in beam 3. H D : Higher D polarization 4. H D Can Select H D H D

Polarize H in HD using polarized ortho -H 2 Ortho HD : L = 0 Spin exchange H H H L =1 H D D H Para H H L = 0 Polarize H at 12mK, 15 T H 2 Age: ~ 3 months 12 mK, 15 T Ortho -> Para (Half in 4.5 days) H H D H D H Para Polarized H in HD H 2 No spin exchange to HD (Frozen Spin)

Expected Polarizations 12 milli−Kelvin and 15 Tesla HD at 15 Tesla 100 H vector D vector Equilibrium Polarization [%] D tensor 80 60 40 20 0 0 10 20 30 40 50 60 70 80 T [mK]

HD target Produced, Calibrated, Polarized and On the beam Down to 10 - 4 of H 2 in HD Distillation PD: 2 K, 2 T (1) HD ice production DF: 12 mK, 15 T TE calibration (2) Polarization Measure. Polarized and Aged (3) Polarization Measure. IBC: 0.3 K, 1 T On Beam Monitor Polarization T1 Measurements : TC: 2 K, 0.12 T

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Summary of HD target polarizations during recent runs at LEGS Year Duration P(D) P(H) Fall 2004 17 days + 7 % + 53 %, - 26 % Spring 2005 32 days + 31 % + 30 %, -7 %

Summary and Rationalization of Fall and Spring Data v1.nb 1 Target #3 Polarization during November 2004 Run 0.8 p in PD p in QIBC d in PD 0.6 d in QIBC T 1 # H ' 241 day 0.4 n o i t a z i r a l 0.2 T 1 # D ' 292 day o P T 1 # D ' 238 day 0 T 1 # H ' 883 day � 0.2 Time + hrs / 0 100 200 300 400 500

Spin transition: H H Allowed fast passage RF transition mD = - 1 a mD = 0 mH = -1/2 b mD = + 1 c mH = +1/2 d e f

✆ ✆ ✞ ✁ ✡ ✠ ✝ ✞✟ � ☞ ✝ � ✂ ✄ ✄ ✂ ✁ ☛ ✌ � ✓ ✕ ✔ ✞ ✎ ✞ ✍ ✒ ✞ ✖ ✠ ✏ ✂ ✎ ✂ ✍ ✍ ✏ ✠ ✂ � ✆ ✞✟ ✝✠ ✡ ✁ ✞ ☛ ☞ ✌ ✞ ✍ ✍ ✏ ✄ ✠ ✑ ✒ ✓ ✘ ✚ ✛ ✞✔ ✕ ✏ ✠ ✎ ✞ ✍ ✝ ✂☎✎ & ✗✙✘ ✂☎✆ ✁✂☎✄ ! "# $ ! ! $ # $ , " ! "# ! Fall'04: P(H) = 53%, 7% % $ P(D) =

Spin transition: H D Saturated Forbidden RF Transition mD = - 1 a mD = 0 mH = -1/2 b mD = + 1 c mH = +1/2 d e f Nd > Nb, Ne > Nc Nd = Nb, Ne = Nc

Summary and Rationalization of Fall and Spring Data v1.nb 1 Target #4 Polarization during April 2005 Run 0.8 7 �O O cccccccc cccc 2 2 H in PD H in QIBC D in PD 0.6 D in QIBC 0.4 T 1 # D ' 345 day n o i t a z i r a T 1 # H ' 187 day l o P 0.2 T 1 # H ' 243 day 0 Time + hrs / 0 200 400 600 800

LEGS production run #2, deepUV-1 (Spring'05) # n) D( ! , " P ! = 92% P D = 31% # n) = 105 o E ! = 341 MeV $ cm ( " 800 800 700 700 helicity 1/2 helicity 3/2 ! + D ! + D 600 600 500 500 400 400 full cell full cell 300 300 empty cell empty cell 200 200 100 100 0 0 -200-150-100 -50 0 50 100 150 200 -200-150-100 -50 0 50 100 150 200 800 800 700 700 helicity 1/2 helicity 3/2 ! + D ! + D 600 600 500 500 400 400 300 300 200 200 100 100 0 0 -200-150-100 -50 0 50 100 150 200 -200-150-100 -50 0 50 100 150 200 E "# Missing Energy (MeV) E "# Missing Energy (MeV) - target cell and Al wires contain the only unpolarizable nucleons; - background is sampled in runs with an empty cell D(g,pi0n)341MeV105 full&empty_FS

- very preliminary - % % $ n) D( " , # 1.0 P D = 30% (avg) 286 ±7 MeV 0.5 Spring'05 asy nd Production run E 2 0.0 $ n) LEGS run#2, deepUV-1 -0.5 D( " , # $ n) T.S.-H. Lee [Impulse] D( " , # $ n) SAID[FA04K] n( " , # -1.0 0 30 60 90 120 150 180 1.0 1.0 349 ±5 MeV 396 ±7 MeV 0.5 0.5 asy E 0.0 0.0 -0.5 -0.5 -1.0 -1.0 0 30 60 90 120 150 180 0 30 60 90 120 150 180 ! Lab (deg) ! Lab (deg)

Experiment schedule - through 2006 : ! ! ! ! D ( ! H ( ! H ( ! H ! " , # o ) to extract ! , " o ) and ! , " + ) ! FallÕ04: ! ! ! D ( ! D ( ! H ! " , # o ) to extract ! , " o ) ! FYÕ05: ¥ SeptÕ05-JanÕ06: install Time-Projection-Chamber H 2 ( ! , " + ) , D 2 ( ! , " ± ) calibrations ¥ FebÕ06 ÐAprÕ06: ! ! D ( ! " , # ± ) - run 1 H ! ¥ MayÕ06 ÐJuneÕ06: ! ! D ( ! " , # ± ) - run 2 H ! ¥ AugÕ06 ÐSeptÕ06: ! ! ! D ( ! D ( ! H ( ! ! , " # ) , ! , " + ) , ! , " + ) extract: ¥ OctÕ06: expected end of LEGS experiments LEGS exp schedule FY05-06

Figures of merit for Butanol and HD Low-resolution high-resolution High Nuclear- Atomic- and Low- Low-Intensity Intensity background-limited background-limited Intensity ! -beam ! -beam High Intensity High Intensity ! -beam ! -beam ! -beam (b) (c) (d) (e) target (a) (P eff ) 2 (P eff ) 2 /A (P eff ) 2 /Z 2 " eff (P eff ) 2 1.4 " eff (P' eff ) 2 Figure of merit 0.017 0.110 0.23 0.0031 0.0069 p in C 4 H 9 OH 0.010 0.010 0.18 0.0021 0.0070 n in C 4 D 9 OD 0.019 0.067 0.45 0.1500 0.4500 p in HD 0.010 0.014 0.46 0.1500 0.4500 n in HD (a) count rate is beam-limited; reactions on p , n distinguished; bound vs free not distinguished; P eff = P ¥ f (b) count rate is beam-limited; reactions on p , n distinguished; bound vs free distinguished with cut; P eff = P ¥ [ P free / (P free + 0.2 ¥ P bound ) ] (c) beam flux can be increased as needed; count rate is limited by accidentals; P eff = P ¥ f (d) beam flux can be increased as needed; count rate is limited by dead time from nuclear events; P eff = P ¥ f (e) beam flux can be increased as needed; count rate is limited by dead time from atomic electrons; P eff = P ¥ f Figures of merit table - Schaerf/Sandorfi Ð NovÕ05

Complete set of measurements with longitudinal target polarization: target beam (1a) P 1 (H) P 1 (D) C R , C L , L (1b) Ð P 1 (H) P 1 (D) C R , C L , L separates ! , G, E (2a) P 2 (H) P 2 (D) C R , C L , L (2b) Ð P 2 (H) P 2 (D) C R , C L , L separates separates r r H and D D vector and D tensor observables observables - example: ! + HD " # o (from LEGS/BNL) complete set of exp

� � ✁ � ✁ � ✁ ✁ Separate reactions to n from p with TPC -- + n p + 0 n + Separate ! + + p n + 0 p +