Advisors: Rurng-Sheng GuoWen-Chen Chang

Graduate: Su-Yin Wang2009/06/19, NKNU

Polarized Hydrogen-Deuteride (HD) Target

for Strangeness Production

Experiments at SPring-8/LEPS

2

Outline

IntroductionPHYDES01 ProductionNMR MeasurementSignal Distortion (Appendix)AnalysisConclusion and DiscussionAcknowledgement

Introduction

Motivation

4 Kinds of Mechanisms of

The γp →φp Reaction

Diffractive production within the vector-meson-dominance model through Pomeron exchange

One-pion-exchange

OZI

uud uud

ss

ss-knockout uud-knockoutA.I.Titov et al. Phys. Rev. C58 (1998) 2429 4

5

Cross sectionCross Section at Eg = 2.0 GeV

Vector-meson-dominance model

One pion exchange

ss knockout

uud knockoutA.I.Titov et al. Phys. Rev. C58 (1998) 2429

Pomeron exchange is more ten times than others. Only the Pomeron exchange is clear.

The experimental data are fromH. J. Besch, G. Hartmann, R. Kose, F. Krautschneider, W.

Paul, and U. Trinks, Nucl. Phys. B70, 257 ~1974!.

6

}]][][[

]][][[{

][

2/112/11

2/102/10

2/1

ssuud

ssuudB

uudAP

Beam-Target double spin asymmetryat Eg = 2.0 GeV

Strangeness content is assumed to be 0%(Solid), 0.25%(Dashed), 1%(Dot-dashed). (0,1) is the relative phase between the strange and non-strange amplitudes.

A.I.Titov et al. Phys. Rev. C58 (1998) 2429

Beam target asymmetrymore sensitive to understand the components of cross section

2/32/1

2/32/1

BTC

7

Identification of Exchange Particle

Example: t-channel exchange of Λ(1520) photoproduction Exchange particle is clear to see, if …

▪ Fix the spin and orientation of initial state particles.▪ The spin and orientation of final state are measured.

Introduction

HD Overview

9

Why we choose HD

Polarized this

Symmetry requirement

hetero-HD (boson “D” and fermion “H”)no Symmetry requirement

polarization is low

18.6 days 6.3 days

10

Small Concentrations of ortho-H2

B0

11

HD Target at Other Laboratories At Institut de Physique Nucleaire de Orsay (IPN

Orsay) Magnetic field ~ 15 Tesla Temperature ~ 10 mK PH~ 60%, PD~14%

12

HD Target at Other Laboratories

At the Laser Electron Gamma Source (LEGS) at Brookhaven National Laboratory Magnetic field ~ 15 Tesla Temperature ~ 15 mK The initial :PH~ 59%, PD~7% With Saturated Forbidden Transition

(SFT): PH~ 32%, PD~33%

13

HD Target Goal

We can use both proton and neutron. Temperature ~ 10 mK Magnetic field ~ 17 Tesla The target production take 2~3

month. The target relaxation time ~1 year. Use the brute force: PH~ 90%,

PD~30%

HD target cell Advantage and Disadvantage

HD molecule does not contain heavy nuclei such as Carbon and Nitrogen.

Good for experiments observing reactions with small cross section

The HD target needs thin aluminum wires (at most 20% in weight) to insure the cooling.

Target Size 25 mm in diameter; 50 mm in thickness

14

15

Cryogenic and Magnet Systems

Distillator

Distillator purify the HD gas up to 99.99%.

16

Cryogenic and Magnet Systems

Dilution Refrigerator System (DRS)

DRS is mainly for making the polarized HD target.T=10mK, B=17T

17

Cryogenic and Magnet Systems

Storage Cryostat (SC)

SC is to keep HD polarization on the way of the transportation from RCNP to Spring8.

In normal case, we measure polarization of HD in SC only.

T~1.2K, B=2.5T.

18

Cryogenic and Magnet Systems

Transfer Cryostat (TC)

The TC1 is mainly for moving the target from the DRS to the SC.

The TC2 is mainlyfor moving the target from the SC to the IBC

T=4.2K, B=0.15T

TC2

TC1

19

Cryogenic and Magnet SystemsIn Beam Cryostat (IBC)

IBC is to cool the target during the experiment at SPring-8.

T=0.3K, B=1T.

20

Transport of Polarization HD Target

0.5 hour

s 3 hours

0.5 hour

s

21

Main Issues are …

TC1 SC TC2 IBC

Magnetic field 0.15T 1.08T 0.15T 1.08T

Temperature 4.2K 1.2K 4.2K 300mK

Time 0.5 hours 3 hours 0.5 hours 100 days

Could we keep the polarization at…

Could we achieve high polarization?

Polarized HYdrogen-DEuteride target for Strangeness (PHYDES)

PHYDES01 Production

HD Purify

H2

HD

D2

Extraction

HD

D2

Extraction

HD

HD

[H] = 1.26%In PHYDES01 [D] =

2.07%[HD] =97.66%

23

Solid HD Production

Normal

production No TC

production

Since TC1 can not

work now

solidify

solidify

24

25

PHYDES01

Process Solidify HD

PHREF

measuring

Aging time

IBC condition

SC condition

TC ~conditio

n

PDREF

measuring

Magnetic field

0T 1.08T 1.08T 1.08T 1.08T 0.15T 7.26T

Temperature

14~22K

4.2K 14mK 0.3K 1.2K 4.2K 4.2K

Time 20081111

20081112

20081114~

20090105

20090105~

20090119

20090119~

20090122

20090127~

20090129

20080217

Time

[HD]=97.66%; 0.68 HD was solidified for PHYDES01.

After 53 days aging, the relaxation time in three conditions are measured.

NMR Measurement

27

Principle of NMR Measurement

nuclear magnetic resonance

0HE

hE

hH0

hH 0

28

The Dispersion Part The net absorption or emission of electromagnetic radiation

by the nuclear spin system can be modeled macroscopically as the imaginary component of complex magnetic susceptibility:

χ(ω) = χ’(ω) + iχ”(ω), Real part = Absorption part.Imaginary part = Dispersion part.

The vector polarization, P, can be written as which forms the basis for the area methods used to determine polarization.'

"

29

Single coil methodCold finger

Cancellation Circuit

When receiver coil receives the signal, the signal come from transmitter but not nuclear magnetic resonance can be canceled easily by cancellation circuit.

Single coil method uses one coil to work as both transmitter and receiver

coil.

16MHz15MHz14MHz30

31

Flow Chart

Shape Distortion

Appendix

33

Account of NMR shape width

The smallest width of the NMR shape can be estimated from the uncertainty principle.

Precision of frequency. The non-uniformity of the local magnetic

field in a superconductor The non-uniformity of the local magnetic

field from the induced current of aluminums wires and cold finger.

1 ;

EE

Cold finger

34

Non-uniformity of Magnetic Field

real012

23

34

4center )PPPP(PB Bxxxx

Breal

ΔBBcenter

ΔBBcenter

Magnetic field uniformity profile Measurement value Fitting by 4th-order polynomial

Simulation

35

Analysis

37

Analysis outline Preparation of Analysis

Unification of the Signal Amplification Magnetic Field Adjustment Data Position Shift Unification of Bin Size Phase Adjustment

Extracting the Signal Area (Relaxation Time) Histogram Method Model Method

Extracting the Signal Area (Polarization) Histogram Method Model with Deviation Method

Error Estimation Relaxation Time Estimation Polarization Estimation

Preparation of Analysis–

Unification of the Signal Amplification

The original data with the sensitivity = (1mVrms/-47dBm)

The signal is 10% of original one. We also change the signal shape to positive. 38

39

Preparation of Analysis–

Magnetic Field Adjustment

B-1 B0 B1 B3B2B-3 B-2 ~ B50B-50 ~

101

50

500

i

iBBreset

40

Preparation of Analysis–

Data Position Shift

After Peak Shift

41

If bad phase … If good phase …

Preparation of Analysis–

Phase Adjustment

Quadrature

In Phase In Phase

Quadrature

PhaseIn

Quadraturecossinsincos

'PhaseIn 'Quadrature

42

Preparation of Analysis–

Remove the Background

Fit each signal in background region

After removing background, for each pulse, start analysis

43

Extracting the Signal Area (Relaxation Time) –

Histogram Method Fit only in

background region fitting

44

D:IBC,18hours,θ=0.4H:IBC,332hours,θ=0.75

Extracting the Signal Area (Relaxation Time) –

Model Method H model

increase

decrease

increase

decrease

D model

Extracting the Signal Area (Relaxation Time) –

ComparisonHistogram Method

45

Model Method

Extracting the Signal Area (Relaxation Time) –

ComparisonHistogram Method

46

Model Method

Histogram method

Two method comparison–

Comparison-big signal Model method

H, TC, increase , 47 hours

47

Histogram method

Relaxation time estimation –

Comparison-small signal Model method

D, TC, decrease ,46hours

48

Extracting the Signal Area (Polarization)–

Necessary to Take AverageZoom in each signal

Average of 73 signals

Average of “Error of each signal” = 2.05E-3

Error of average signal = 2.72E-4Signal height ~ 1 .5E-3

49

Can not shift the position of each signal before taking average.

Extracting the Signal Area (Polarization) –

Model Method

Bad fitting by signal deviation

50

51

Extracting the Signal Area (Polarization) –

Consider Smearing of Signals

52

Extracting the Signal Area (Polarization) –

Smearing Model MethodGauss deviation=2.6094655E-04

D model at 300mK, 1.08T

D model with Gauss deviation

BackgroundNormalization

Sigma of Smearing

BackgroundNormalization

Extracting the Signal Area (Polarization) –

Flow Chart

53

Extracting the Signal Area (Polarization) –

ComparisonHistogram Method

54

Smearing Model Method

55

Polarization and Relaxation Time

1

1

)0()(

)0()(

targetthermal_eqtarget

target

targetthermal_eqtarget

ref

targetreftarget

Tt

Tt

eAAtA

areasignalonpolarizatiN

eNNtN

AAP

P

polarization at thermal equilibrium state polarization decay function combine two function

56

Fill histogram

Fill histogram

left

right

combine

Original

New error

Estimation of Statistical Error

sizebin bin ofnumber 000863.0Area of 0.000863 valueRMS Bin Each of

stat

stat

EE

57

Estimation of Systematic Error

2decreaseincrease

aveAAA

22 )()( avedecreaseaveincreasesys AAAAE

sysstatfinal EEE 22

) )2

( ( 2decreaseincreasesys

AAE

58

D

Result

Good consistency

Bad consistency

59

Result When extract the signal area of polarization,

peak up the smearing model method. When extract the signal area of relaxation

time, peak up the histogram method.

[M]

[M]

Conclusion

and Discussio

n

61

HD Target GoalGoal PHYDES01

Temperature during aging 10 mK 14 mKMagnetic field during aging 17 Tesla 17 TeslaTime of target production 2~3 month 53 daysRelaxation time of target ~1 year T1

H=106 days; T1D=73

daysPolarization of H 90% Theoretical ： 85 ％

Measured ： 41.4 ％Polarization of D 30 ％ Theoretical ： 25 ％

Measured ： 13.1 ％

62

Back to the Main Issues

TC1, TC2 SC IBCMagnetic field 0.15T 1.08T 1.08TTemperature 4.2K 1.2K 300mKTime 0.5 hours 3 hours 100 daysT1

H 147 hours 281 hours

106 days

T1D 48 hours 303

hours73 days

Could we keep the polarization at…

Could we achieve high polarization?

PH PD

41.4% 13.1%

63

Conclusion The production of polarized HD target succeeded. But

the polarization degrees measured are much lower than those expected from the thermal equilibrium state of the aging condition. Non-linear relation between the NMR signal height and the polarization degree is considered to be a main source of the low polarization degree.

The relaxation times in the SC and TC condition are found to be long enough compared with the staying time needed for the transportation of the HD target.

The relaxation time in the IBC condition is found to be long enough to produce a new polarized HD target for replacement in continuous experiments.

64

Discussion

Study of Aging Time Lower Polarization NMR Measurement Improvement of D Polarization From Success of Polarized HD Target to Using the Polarized

HD Target in LEPS Experiment

65

NMR Measurement-Frequency Sweeping or Magnetic Field Sweeping

For sweeping magnetic field, one need to break superconductor-state of magnet, and turn the magnet to drive-state. It waste a lot of liquid helium.

If the polarization of D and H are both measured, the magnetic field sweep from 1T to 7T will generate a lot of heat and waste a lot of liquid helium.

The significant change of magnetic field, make the polarization of HD unstable.

Cannot be avoided

Can be avoided easy by separating the cancellation circuits of H and D,

Study of Aging Time-Data comparison (consider [O-H2])

66

67

From Success of Polarized HD Target to Using the Polarized HD Target in LEPS Experiment

There are still many subjects that we have to work on: Installation of HD target system in the

LEPS experiment hutch. The transit of HD target from RCNP to

SPring-8/LEPS. Acceptable trigger rate for data taking.

68

Acknowledgement

Whole HD Members, especially for : 藤原　守、與曽井 優 郡　英輝、太田 岳史 福田 耕治、國松 貴之 上田 圭祐、森崎 知治

Advisors: 郭榮升 章文箴

End

Thank you for your kind attention.

70

71

72

Advanced Simulation The PHYDES01 use 0.68 mole HD only. The smallest cell

size is 34 mm. The biggest size is 80 mm (the length of aluminums)

This result shows the most likely cell position around -14 cm and cell length around 46 mm.

73

Lower Polarization

The polarization degree expected by the aging process is about PH~ 85% and PD~25%.

The polarization degree was obtained as about PH~ 41% and PD~13%.

Bad Linearity of the NMR Signal Height Improvement of Thermal Conduction

Make a new target cell with high purity aluminum wires.

Develop the single crystal HD target.

Improvement of D Polarization Forbidden Adiabatic Fast Passage (FAFP) and Saturated Forbidden Transition

(SFT)

D. Babusci et al., LEGS expt. L18/L19 (1994).

The time linefrom LEGS group

74

75

Improvement of D Polarization

The Difficulties of FAFP and SFT The concentration of o-H2 can not be handled easy

now. The concentration of p-D2 can not be handled easy

now. (p-D2 should be ~0)

The amounts of heat depend on the amounts of HD and RF power.

The relation between concentration of o-H2 and the relaxation time of H is not well known enough.

76

Target temperature ?

H DPolarization 41.4% 13.1%Temperature estimate by the polarization(Assume B=17T)

~40mK ~27mK

Bad linearity of the NMR signal height.

Bad Thermal conductivity of Al wires or Kel-F NMR coil supporter

"')41(

11

0

g

iLL

LjCj

Z

ZIV

21 ;575.42

1 ;5356.6

1885.0)1()1(

2

2

HH

DD

HHH

DDDH

D

I

I

IIII

g

g

gg

Remained Polarization TC1 SC TC2 IBC

Magnetic field 0.15T 2T 0.15T 1TTemperature 4.2K 1.2K 4.2K 300mK

Time 0.5 hours 3 hours 0.5 hours 100 daysH Relaxation time ~147 hours ~277 hours ~147 hours ~2546 hours

Remained Polarization of Init PH 99.66% 98.58% 98.24% 38.27%Init PH = 41.4 % 41.46 40.81 40.67 14.62

D Relaxation time ~48 hours ~303 hours ~48 hours ~1740 hoursRemained Polarization of Init PD 98.96% 97.98% 96.96% 24.41%

Init PD = 12.2 % 12.07% 11.83% 11.83% 2.95%

77

78

HysteresisHysteresis from cold finger and aluminum wire

79

Extracting the Signal Area (Relaxation Time) –

Histogram Method

80

Next improvement

NMR system – to correctly measure the polarization.

NMR system – to increase Signal/Noise ratio.

Al wires or NMR coil supporter -to decrease the HD temperature.

Distillator- to improve the purity of HD

81

Next progress Practice of transferring the target by using a solid H2 target A polarized HD target after the aging of 2~3 months will be ready for

the experiment. install the HD target system in the LEPS experiment hutch. (

Support frames for the IBC and TC2 will be constructed. IBC and TC2 will be transferred from RCNP to SPring-8/LEPS.

Circularly polarized ultra-violet laser beam will be prepared. Check the polarization of the HD target can be kept when the photon

beams of ~1 M γ‘s hit the target. Check trigger rate for data taking is acceptable.

82

Histogram area

Relaxation time estimation –

Comparison-big signal Histogram model

D, IBC, decrease ,69hours

83

Resonance frequency 48.395 MHzH D

gyromagnetic ratio 42.575 6.536Resonance magnetic field 1.1366 7.4044polarization 41.4 ± 3.1% 12.2 ± 1.7%IBC (300mK, 1.0758T)After 53 days aging.

Relaxation time 2546 ± 380 hours (106.1±15.8 days)

1907 ± 273.3 hours(79.5± 11.4 days)

χ2/ndf 1.529/6 0.3354/2SC (1.2K, 1.0758T)After 67 days aging.

Relaxation time 237.5± 12.8 hours (9.9± 0.5 days)

290 ± 44.2 hours(12.1± 1.8 days)

χ2/ndf 1.141/2 0.003523/1TC (4.2K, )After 75 days aging.

Relaxation time 141.4 ± 2.5 hours (5.9± 0.1 days)

44.0± 4.6 hours(1.8± 0.2 days)

χ2/ndf 0.01367/1 0.6168/2

Model method

Resonance frequency 48.395H D

gyromagnetic ratio 42.575 6.536Resonance magnetic field 1.1366 7.4044polarization 41.4 ± 3.1% 13.8 ± 2.2%IBC (300mK, 1.0758T)After 53 days aging.

Relaxation time 2546 ± 380 hours (± days)

1740± 167.6 hours(± days)

χ2/ndf 1.529/6 2.794/2SC (1.2K, 1.0758T)After 67 days aging.

Relaxation time 281.2± 25.6hours (11.7±1.1 days)

302.5 ± 28.6 hours(12.6±1.2 days)

χ2/ndf 1.141/2 0.01654/1TC (4.2K, )After 75 days aging.

Relaxation time 147.3± 3.842 hours (6.1±0.2 days)

47.8± 5.6 hours(2.0± 0.2days)

χ2/ndf 0.7588/1 1.059/2

Histogram method

H Polarization & IBC dataC. Morisaki, Master thesis of Osaka university (2009).

84

Data comparision

85

Cross sectionCross Section at Eg = 2.0 GeV

Vector-meson-dominance model

One pion exchange

ss knockout

uud knockoutA.I.Titov et al. Phys. Rev. C58 (1998) 2429

Pomeron exchange is more ten times than anothers Only the Pomeron exchange is clear.

The experimental data are fromH. J. Besch, G. Hartmann, R. Kose, F. Krautschneider, W.

Paul, and U. Trinks, Nucl. Phys. B70, 257 ~1974!.

86

Scattering angle

LEPS data :LD2

LAB angle

CM angle

87

Beam target asymmetrymore sensitive to understand the components of cross section

PA

PABTC

bca

cbacba

AP

AP

A

P

222

Cancel the systematic error

P

A

g

g

p

p

88

p A (g:+1 p:+1/2) (g:+1 p:-1/2)

S=+1

S=+1

S=+2

S=-1/2 S=-1/2

S=+1

S=-1

S=0

S=+1/2 S=+1/2

S=+1

S=0

S=+1

S=-1/2 S=-1/2

S=+1

S=0

S=+1

S=+1/2

S=+1/2CANCELCANCEL

p: polarization of proton is parallel with polarization of target A: polarization of proton is anti-parallel with polarization of target

g g pp

AP

APBTC

content ss

89

Experimental ConditionsPhoton beam polarization

Circular polarization

Photon beam energy E=1.5-2.4 GeVPhoton beam intensity 106 γ's/secSpectrometer Standard LEPS magnetic spectrometer

Tagger, SC, AC, SVTX, DC1, DC2, DC3, and TOF wall

90

Phase adjustment

PhaseIn

Quadraturecossinsincos

'PhaseIn 'Quadrature

θ=0

θ=0.8

θ=0

Reference signal peak up

Appendix

92

Ref signal peak up

93

Ref signal peak up

94

Ref signal peak up

95

Ref signal peak up0212 increase

Big range Small range

96

Ref signal peak up

97

Ref signal peak up

98

Ref signal peak up

99

Ref signal peak up

100

Ref signal peak up

101

Brute force Magnetic field=17T Temperature=17mK

Cooling pow

er

DRSThermal sensor

HD target

102

Get empty cell

the

Log P

Time

Empty cellHD