Advisors: Rurng-Sheng Guo Wen -Chen Chang Graduate: Su-Yin Wang 2009/06/19, NKNU

1. Polarized Hydrogen-Deuteride (HD) Target for Strangeness Production Experiments at SPring-8/LEPS Advisors: Rurng-Sheng Guo Wen-Chen Chang Graduate: Su-Yin Wang 2009/06/19, NKNU

2. Outline • Introduction • PHYDES01 Production • NMR Measurement • Signal Distortion (Appendix) • Analysis • Conclusion and Discussion • Acknowledgement

3. Introduction Motivation

4. 4 Kinds of Mechanisms ofThe γp→φp Reaction OZI ss uud uud Diffractive production within the vector-meson-dominance model through Pomeron exchange One-pion-exchange uud-knockout ss-knockout A.I.Titov et al. Phys. Rev. C58 (1998) 2429

5. Cross section Vector-meson-dominance model Cross Section at Eg = 2.0 GeV The experimental data are from H. J. Besch, G. Hartmann, R. Kose, F. Krautschneider, W. Paul, and U. Trinks, Nucl. Phys. B70, 257 ~1974!. One pion exchange ss knockout Pomeron exchange is more ten times than others. Only the Pomeron exchange is clear. uud knockout A.I.Titov et al. Phys. Rev. C58 (1998) 2429

6. Beam target asymmetrymore sensitive to understand the components of cross section Beam-Target double spin asymmetryat Eg = 2.0 GeV Strangeness content is assumed to be 0%(Solid), 0.25%(Dashed), 1%(Dot-dashed). (h0,h1) is the relative phase between the strange and non-strange amplitudes. A.I.Titov et al. Phys. Rev. C58 (1998) 2429

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.

8. Introduction HD Overview

9. Why we choose HD Symmetry requirement polarization is low 6.3 days 18.6 days Polarized this hetero-HD (boson “D” and fermion “H”) no Symmetry requirement

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%

14. 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

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 mainly for moving the target from the SC to the IBC TC2 TC1 T=4.2K, B=0.15T

19. Cryogenic and Magnet Systems In 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 3 hours 0.5 hours 0.5 hours

21. Main Issues are … Could we achieve high polarization? Could we keep the polarization at…

22. Polarized HYdrogen-DEuteride target for Strangeness (PHYDES) PHYDES01 Production

23. HD Purify [H]=1.26% In PHYDES01 [D]=2.07% [HD]=97.66% HD HD Extraction H2 HD D2 HD D2 Extraction

24. Solid HD Production Since TC1 can not work now solidify solidify Normal production No TC production

25. PHYDES01 [HD]=97.66%; 0.68 HD was solidified for PHYDES01. After 53 days aging, the relaxation time in three conditions are measured. Time

26. NMR Measurement

27. Principle of NMR Measurementnuclear magnetic resonance

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 method Cold finger

30. Cancellation Circuit Single coil method uses one coil to work as both transmitter and receiver coil. When receiver coil receives the signal, the signal come from transmitter but not nuclear magnetic resonance can be canceled easily by cancellation circuit. 14MHz 15MHz 16MHz

31. Flow Chart

32. Appendix • Shape Distortion

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. Cold finger

34. Non-uniformity of Magnetic Field Magnetic field uniformity profile Measurement value Fitting by 4th-order polynomial Breal ΔB Bcenter ΔB Bcenter

35. Simulation

36. 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

38. 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.

39. Preparation of Analysis– Magnetic Field Adjustment B-3 B-2 B-1 B0 B1 B2 B3 ~ B-50 ~ B50 reset

40. Preparation of Analysis– Data Position Shift After Peak Shift

41. Preparation of Analysis– Phase Adjustment • If bad phase … • If good phase … Quadrature Quadrature In Phase In Phase

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. Extracting the Signal Area (Relaxation Time) – Model Method • H model • D model increase increase decrease decrease H:IBC,332hours,θ=0.75 D:IBC,18hours,θ=0.4

45. Extracting the Signal Area (Relaxation Time) – Comparison Histogram Method Model Method

46. Extracting the Signal Area (Relaxation Time) – Comparison Histogram Method Model Method

47. Two method comparison– Comparison-big signal • Histogram method • Model method H, TC, increase , 47 hours

48. Relaxation time estimation – Comparison-small signal • Histogram method • Model method D, TC, decrease ,46hours

49. Extracting the Signal Area (Polarization)– Necessary to Take Average Zoom in each signal Average of “Error of each signal” = 2.05E-3 Error of average signal = 2.72E-4 Signal height ~ 1 .5E-3 Average of 73 signals Can not shift the position of each signal before taking average.

50. Extracting the Signal Area (Polarization) – Model Method Bad fitting by signal deviation