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HD target

HD target. HD target overview. Characteristics of polarized HD target. Polarization Method HD target is polarized by the static method using “brute force” at low temperature (10 mK) and high magnetic field (17 T). It takes about 2-3 months to polarize the target.

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HD target

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  1. HD target

  2. HD target overview

  3. Characteristics of polarized HD target Polarization Method HD target is polarized by the static method using “brute force” at low temperature (10 mK) and high magnetic field (17 T). It takes about 2-3 months to polarize the target. 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. Polarization H : 90 % D : 60 % Relaxation Time 30 days at 200 mK and 1 T during the experiment. Target Size 25 mm in diameter 50 mm in thickness

  4. RCNP Osaka university HD target transportation Transfer Cryostat 1 From RCNP to SPring-8 Storage Cryostat BL33LEP SPring-8 Experiment In Beam Cryostat Transfer Cryostat 2 Dilution Refrigerator K+ g HD Target K-

  5. Dilution refrigerator Leiden Cryogenics DRS-3000(He3-He4) Cooling power 3000μW at 120 mK Lowest temperature 6 mK Magnetic Field 17 T Homogeneity of Magnetic Field 5×10-4 for 15 cm

  6. Two Transfer Cryostats Right : used at RCNP Left : used at SPring-8

  7. IBC（In Beam Cryostat） for BL33LEP 2.5cm Al wire

  8. NEXT • Develop NMR system • To advance the dilution refrigeration • pure HD gas • To advance the connector from target to cooling system

  9. Temperature calculation of HD target

  10. Temperature calculation of HD target by M. M. Lowry. M M Lowry, F Lincoln, L Miceli, T Saitoh, A Sandorfi, X Wei, C Whisnant. Progress on the LEGS polarized HD target. Int'l workshop on polarized beams and polarized targets, PST 2001, Vol Sept 2001, (2001)

  11. Q Area T1 Al （W/k-m） Q = heat flow rate = 0.5 μW ΔT = temperature difference =T2 -T1 L = the length of aluminum wire = 5 cm A = (section area of one aluminum wire) × (number of aluminum wire) = × (Diameter of wire)2 × (Number of wire) T2 Thermal conductivity of Aluminum L

  12. T0 Al T1 ΔL T2 TN Aluminum wire temperature We cut the aluminum wire to N part κ(figure) = κAl / TAl κAl = κ(figure) ×TAl ΔL = (the length of aluminum wire ) /N ...

  13. T of wire at ring 17 mk 3cm T of wire at top of HD 17.359 mk 2.5cm T of wire at middle of HD 17.653 mk 2.5cm T of wire at end of HD 17.941 mk Q = Ortho Decay Heating = 0.5 μW Wire material = 99.999% Al Number of wire = 2000 Diameter of wire = 50.8 μm Thermal conductivity of Al wire = 600 W/m/K^2 T of wire at ring 17 mk 3cm T of wire at top of HD 113.249 mk 2.5cm T of wire at middle of HD 152.539 mk 2.5cm T of wire at end of HD 183.604 mk Q = Ortho Decay Heating = 0.5 μW Wire material = Al 5056 Number of wire = 3000 Diameter of wire = 38.1 μm Thermal conductivity of Al wire = 0.7 W/m/K^2 T of wire at middle of HD

  14. HD temperature next to aluminum wire Kapitza resistance = Thermal boundary resistance =Contact resistance

  15. HD temperature next to aluminum wire A. Honig, Q. Fan ,X Wei, A. M. Sandorfi, C. S. Whisnant, Nuclear Instruments and Methods in Physics Research Section A 356 39-46 (1995) Q (A. Honig) = heat flow rate = 2.8×10-8 (W) Dwire (A. Honig) = diameter of wire = 50 μm Nwire (A. Honig) = number of wire = 60 L wire (A. Honig) = length of wire = 5 cm A surface (A. Honig) = (surface area of one aluminum wire) * Nwire = π × (Diameter of wire) × (Length of wire) × (Number of wire) = π × (0.000050) × (0.05) × (60) (m^2) = 0.000471 (m^2)

  16. HD temperature next to aluminum wire • The Kapitza resistance is 405422304 (W/ (m^2) (mk^3)). • The error of kapitza resistance is 32802524 (W/ (m^2) (mk^3)) • Q = Ortho Decay Heating = 0.5 μW • Wire material = 99.999% Al • Number of wire = 2000 • Diameter of wire = 50.8 μm • Length of wire = 5 cm • TAl = 17.653 mk • Asurface = π × (Diameter of wire) × (Length of wire) × (Number of wire) • =π × (0.0000508) × (0.05) × (2000) (m^2) • = 0.0159593 (m^2) • THD = • = (mk) • = 19.9619 ±0.186813 (mk) T of wire at middle of HD

  17. thermal conductivity of HD time →∞ , c→ 0 Where α, β, γ, δ, σ are constants, which given by REF3, α=0.099, β=1.32×10-3, γ= 0.57, δ=0.0031, σ=3.34 ×10-3 Where “T” is the temperature of HD. Where “c” is the (J=1) concentration. J = rotational quantum number o-H2 (J=1) p-H2 (J=0)

  18. HD temperature farthest to aluminum wire J. H. Constable and J. R. Gaines, Phys. Rev. B 8,3966 (1973)

  19. HD q ri Al ro HD temperature farthest to aluminum wire this boundary conditions T = Ti at r = ri T = To at r = ro

  20. HD temperature farthest to aluminum wire ...

  21. Use computer to calculate temperature

  22. T of wire at ring 17 mk 3cm T of wire at top of HD 17.359 mk 2.5cm T of wire at middle of HD 17.653 mk • T of HD next to HD 19.9619±0.186813 mk 2.5cm T of HD farthest of wire 20.0952 mk T of wire at end of HD 17.941 mk Q = Ortho Decay Heating = 0.5 μW Wire material = 99.999% Al Number of wire = 2000 Diameter of wire = 50.8 μm Thermal conductivity of Al wire = 600 W/m/K^2 Volume ratio ( Al /(HD+Al)) = 0.00825805 Calculation of various HD target

  23. purify HD

  24. purify HD

  25. Distillator top D2 solid, H2 gas, HD liquid middle D2 solid, H2 gas, HD gas bottom D2 solid, H2 gas, HD gas

  26. HD～99.999％ H2 H2～50％ H2～2％ 2 week 2 week HD～50％ HD～96％ H2～4~6％ HD~95% D2～2％

  27. principle of concentration sensor • use filament to ionize gas H2+ AMP (amplifier) sensor ionize gas here HD+ digital data D2+ In amplifier, use different gain for each gas PC

  28. pressure controller concentration sensor bottom middle top throw gas out pressure monitor Distillator

  29. concentration measurement D B F A H I C gas here gas here gas here E gas here gas here 0. A ,Bshould closed, open D and G, measure background. 1. open A, get gas for top of Distillator. J G 2. close D, open B, then close B, now gas in C. gas outside 3. open D, then close D, now gas from C to E 4. control pressure by F, see J the pressure should be 9.0x10-7 mbar 5. measure gas concentration by RGA (Residual gas Analyzer) 6. close the software RGA 7. open G, then close G throw the gas away

  30. Physics objectives • To investigate the ss content in the nucleon by the gp -> fp (gn -> fn) reaction To know the structure of the proton and neutron correctly is the fundamental desire. • To determine the spin-parity of Q+ particle Although I do not follow recent theoretical studies, to fix the initial nucleon spin and photon polarization must be important. 3To study the reaction mechanism of the hyperon photoproduction Recently some interesting results measuring the double polarization observables appeared. Advanced studies need the polarized nucleon target.

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