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

@ PST05, Nov.14-17, 2005

• T. Kageya1,2
• n 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

Performances of frozen-spin polarized HD targets for Nucleon spin experiments.

Motivation Motivation

Nucleon Spin Sum Rules

Gerasimov−Drell−Hearn

Nucleon spin strucure at Q2=0 LEGS covers ~65% Measurement down to pion threshold is important

Forward Spin−Polarizability

Test of chiral perturbation theories LEGS covers ~90% Measurement down to pion threshold is important

γ

dE

3 γ

E

3/2

σ

• 1/2

σ

∞

π

m

∫

2

π 4 1 = γ

γ

dE

γ

E

3/2

σ

• 1/2

σ

∞

π

m

∫

2

π 4 1 =

2

κ

2

2m α

• Multipole Amplitudes

Double polarization observables

Asymmetries E and G Neutron channels πon 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

H 2

Ortho -> Para Para

Polarize H at 12mK, 15 T

Spin exchange

Polarized H in HD H 2

Ortho Para

HD : L = 0

L =1 L = 0

No spin exchange to HD (Frozen Spin)

H H H H H H H H H H H D D D D

12 mK, 15 T Age: ~ 3 months

(Half in 4.5 days)

20 40 60 80 100 10 20 30 40 50 60 70 80 Equilibrium Polarization [%] T [mK] HD at 15 Tesla H vector D vector D tensor

Expected Polarizations

12 milli−Kelvin and 15 Tesla

HD target Produced, Calibrated,

Polarized and On the beam

Down to 10 - 4 of H2 in HD

PD: 2 K, 2 T DF: 12 mK, 15 T IBC: 0.3 K, 1 T : TC: 2 K, 0.12 T

Polarized and Aged Distillation (1) HD ice production TE calibration (2) Polarization Measure. (3) Polarization Measure. On Beam Monitor Polarization T1 Measurements

Cross-Coil NMR for Measuring Target Polarization

H D

Typical NMR Scans for the SPHICE Target at TE

Hydrogen Deuterium

Up Down Up Down

NMR Signal =

Summary of HD target polarizations during recent runs at LEGS

Fall 2004 17 days + 7 % + 53 %, - 26 % Year Duration P(D) P(H) Spring 2005 32 days + 31 % + 30 %, -7 %

100 200 300 400 500 Time +hrs/ 0.2 0.2 0.4 0.6 0.8 n

• i

t a z i r a l

• P

Target #3 Polarization during November 2004 Run T1#D' 238 day T1#H' 241 day T1#D' 292 day T1#H' 883 day p in PD p in QIBC d in PD d in QIBC

Summary and Rationalization of Fall and Spring Data v1.nb 1

Spin transition: H H Allowed fast passage RF transition

mD = - 1 mD = 0 mD = + 1 a b c mH = -1/2 mH = +1/2 d e f

!

• "#

• ✆

!

$

!

!

• "#

• ✆

!

$

%

$,"

# $

&

Fall'04: P(H) = 53%, P(D) = 7%

Spin transition: H D Saturated Forbidden RF Transition

mD = - 1 mD = 0 mD = + 1 a b c mH = -1/2 mH = +1/2 d e f

Nd > Nb, Ne > Nc Nd = Nb, Ne = Nc

200 400 600 800 Time +hrs/ 0.2 0.4 0.6 0.8 n

• i

t a z i r a l

• P

Target #4 Polarization during April 2005 Run T1#D' 345 day T1#H' 187 day T1#H' 243 day

7O cccccccc 2 O cccc 2

H in PD H in QIBC D in PD D in QIBC

Summary and Rationalization of Fall and Spring Data v1.nb 1

100 200 300 400 500 600 700 800

• 200-150-100 -50

50 100 150 200 helicity 1/2

! + D

empty cell full cell 100 200 300 400 500 600 700 800

• 200-150-100 -50

50 100 150 200 helicity 3/2

! + D

empty cell full cell 100 200 300 400 500 600 700 800

• 200-150-100 -50

50 100 150 200 E

"# Missing Energy (MeV)

helicity 1/2

! + D LEGS production run #2, deepUV-1 (Spring'05)

D(!,"

#n)

P

! = 92% P D = 31%

E! = 341 MeV $

cm(" #n) = 105

• 100

200 300 400 500 600 700 800

• 200-150-100 -50

50 100 150 200 E

"# Missing Energy (MeV)

helicity 3/2

! + D

• 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

• 1.0
• 0.5

0.0 0.5 1.0 30 60 90 120 150 180

E

asy

286 ±7 MeV

• 1.0
• 0.5

0.0 0.5 1.0 30 60 90 120 150 180

E

asy

!Lab (deg) 349 ±5 MeV

• 1.0
• 0.5

0.0 0.5 1.0 30 60 90 120 150 180 D(",#

$n) LEGS run#2, deepUV-1

D(",#

$n) T.S.-H. Lee [Impulse]

n(",#

$n) SAID[FA04K]

!Lab (deg) 396 ±7 MeV

D(",#

$n)

P

D = 30% (avg)

Spring'05 2

nd Production run % %

• very preliminary -

LEGS exp schedule FY05-06

Experiment schedule - through 2006 : ! FallÕ04: ! H ! ! D(! " ,# o) to extract ! H(! ! ," o) and ! H(! ! ," +) ! FYÕ05: ! H ! ! D(! " ,# o) to extract ! D(! ! ," o)

¥ SeptÕ05-JanÕ06: install Time-Projection-Chamber ¥ FebÕ06 ÐAprÕ06:

H2(! ," +) , D2(! ," ±) calibrations

¥ MayÕ06 ÐJuneÕ06:

! H ! ! D(! " ,# ±) - run 1

¥ AugÕ06 ÐSeptÕ06:

! H ! ! D(! " ,# ±) - run 2

extract:

! D(! ! ," #), ! D(! ! ," +), ! H(! ! ," +)

¥ OctÕ06: expected end of LEGS experiments

Figures of merit table - Schaerf/Sandorfi Ð NovÕ05

Figures of merit for Butanol and HD

target Low-resolution and Low- Intensity !-beam

(a)

high-resolution Low-Intensity !-beam

(b)

High Intensity !-beam

(c)

Nuclear- background-limited High Intensity !-beam

(d)

Atomic- background-limited High Intensity !-beam

(e)

Figure

• f merit

"eff (P eff)2 1.4 " eff (P' eff)2 (P eff)2 (P eff)2/A (P eff)2/Z2 p in C4H9OH 0.017 0.110 0.23 0.0031 0.0069 n in C4D9OD 0.010 0.010 0.18 0.0021 0.0070 p in HD 0.019 0.067 0.45 0.1500 0.4500 n in HD 0.010 0.014 0.46 0.1500 0.4500

(a) count rate is beam-limited; reactions on p, n distinguished; bound vs free not distinguished; Peff = P¥f (b) count rate is beam-limited; reactions on p, n distinguished; bound vs free distinguished with cut; Peff = P¥[ Pfree / (Pfree + 0.2¥Pbound) ] (c) beam flux can be increased as needed; count rate is limited by accidentals; Peff = P¥f (d) beam flux can be increased as needed; count rate is limited by dead time from nuclear events; Peff = P¥f (e) beam flux can be increased as needed; count rate is limited by dead time from atomic electrons; Peff = P¥f

complete set of exp

Complete set of measurements with longitudinal target polarization: target beam (1a) P1(H) P1(D) CR , CL , L (1b) Ð P1(H) P1(D) CR , CL , L (2a) P2(H) P2(D) CR , CL , L (2b) Ð P2(H) P2(D) CR , CL , L separates separates

r H and r D

Dvector and Dtensor

• bservables
• bservables
• example: ! + HD " #o (from LEGS/BNL)

separates !, G, E

Separate reactions to n from p with TPC + n

• p +

• n +

+ p

• n +

+

• p +

Separate !

Central tracking_OctÕ05

Central tracking with magnetic analysis in a Time-Projection Chamber

¥ isolate neutron reactions: ! + n " #Ð p separate D(!, "Ð p) from D(!, "+ n) measure the #± charge TPC Large-bore 2 tesla solenoid p " - " +

LEGS spin experiments

• 1. Compton backward-scattered polarzied γ beam
• 3. Polarized HD solid target

0.17 < Eγ < 0.42 GeV < Pγ > ∼ 90 %

• 2. 4 π detector

(σ1/2 − σ3/2)/ Εγ ;

Total cross sections

The LEGS-Spin Collaboration

¥ Brookhaven National Laboratory

• A. Caracappa, S. Hoblit, O. Kistner, F. Lincoln, L. Miceli, M. Lowry, A.M. SandorÞ *, C. Thorn, X. Wei

¥ Forschungszentrum JŸlich GmbH

• M. Pap, H. GlŸckler, H. Seyfarth, H. Stršher

¥ James Madison University

• C. S. Whisnant

¥ Norfolk State University

• M. Khandakar

¥ Ohio University

• C. Bade, K. Hicks *, M. Lucas, J. Mahon, S. Kizigul

¥ Syracuse University

• A. Honig

¥ University di Roma - Tor Vergata

• A. DÕAngelo *, A. dÕAngelo, D. Moricciani, C. Schaerf, R. Di Salvo, A. Fantini

¥ University of South Carolina

• K. Ardashev, C. Gibson, B. M. Preedom *, A. Lehmann

¥ University of Virginia

• S. Kucuker, R. Lindgren, B. Norum, K. Wang

¥ Virginia Polytechnic Institute & State University

• M. Blecher, T. Kageya

37 people from 10 institutions in 3 countries

LSC list MayÕ05

Post-Docs (NSF) Grad Students * LSC Executive com

γ γ γ γ e e′ ′ ′ ′ Laser-Electron-Gamma-Source (LEGS)

4ω ω ω ω Nd-YLF ring laser

Ar-Ion laser λ λ λ λ(nm) 263 300 351 488 515 Eγ

γ γ γ

(max) 471 MeV 421 MeV 368 MeV 275 MeV 262 MeV NSLS Ee = 2.8 GeV

200 250 300 350 400 Intensity (arb. units) E

(MeV) 263 nm & 351 nm 263 nm only

Eγ

γ γ γ

400 300

γ γ γ γ beam energy determined by e′

′ ′ ′ tagging

Eγ

γ γ γ = Ee - Ee′ ′ ′ ′ , ∆

∆ ∆ ∆Eγ

γ γ γ = 3 MeV

E

tag

(min) = 150-180 MeV

SASY SASY Current Current Setup Setup γ

Separating H and D data

Separating ! H and ! D data with spin flip

• example, !o production

Run A:

! H ! ! D with parallel spins

Run B:

! H ! " D with anti-parallel spins ! !

" L A = !

" p(! " ,# o) $ % & ' + ! " D(! " ,# o) $ % & ' ! "

" R A = !

" p(" " ,# o) $ % & ' + ! " D(" " ,# o) $ % & ' ! !

" L B = !

! p(! " ,# o) $ % & ' + ! " D(! " ,# o) $ % & ' ! "

" R B = !

! p(" " ,# o) $ % & ' + ! " D(" " ,# o) $ % & ' !"(p) = " 3/2 # " 1/2

( )p = " !

$ R B # " ! $ R A

% & ' ( + " "

$ L A # " " $ L B

% & ' (

from "p # !op $

!"(D) = " 3/2 # " 1/2

( )D = " !

$ L A # " " $ R B

% & ' ( + " !

$ L B # " " $ R A

% & ' ( from "D # !oX

• similarily, runs with different PD separate Vector and Tensor D-observables
• in general, one fits out different observables from runs with different polarizations

!,"

#

"

#

!,"

#

!,"

#

$ µ ! ! "

#

Before After After

D

Before

H

Forbidden Adiabatic Fast Passage

Efficiency of transfer = 67%

!

! "#

! "# $

• %, &,

#

(!)

HD target cycle:

target injection into dilution fridge; ~min 45 days at 15 Tesla / 12 mK

loading In-Beam-Cryostat

¥ 0.25!K and 1.00 Tesla extraction with Transfer-Cryostat ¥ 2.5!K and 0.120 T

5 cm

HD target cycle-OctÕ04