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
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