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J-PARC でのハイパー核ガンマ線分光実験に向けた Hyperball-J の建設状況

J-PARC でのハイパー核ガンマ線分光実験に向けた Hyperball-J の建設状況. 東北大理、 KEK 、 セイコー EG&G 、 富士電機システムズ 白鳥昂太郎、 田村裕和、 小野浩、 笠見勝裕、 小池武志、 竹内孝行、 千賀信幸、 春山富義、 保川幸雄 and the Hyperball-J collaboration. Contents. Hyperball-J Design Mechanical cooling system Radiation damage R&D Summary. Hyperball-J.

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J-PARC でのハイパー核ガンマ線分光実験に向けた Hyperball-J の建設状況

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  1. J-PARCでのハイパー核ガンマ線分光実験に向けたHyperball-Jの建設状況J-PARCでのハイパー核ガンマ線分光実験に向けたHyperball-Jの建設状況 東北大理、 KEK、 セイコーEG&G、 富士電機システムズ 白鳥昂太郎、 田村裕和、 小野浩、 笠見勝裕、 小池武志、 竹内孝行、 千賀信幸、 春山富義、 保川幸雄 and the Hyperball-J collaboration

  2. Contents • Hyperball-J • Design • Mechanical cooling system • Radiation damage • R&D • Summary 2007 JPS in Hokkaido University

  3. Hyperball-J

  4. E13 experiment at J-PARC Several light hypernuclear g-ray spectroscopy experiments are planned. (4LHe,7LLi, 10LB, 11LB, 19LF) • Ge detector×32 • 70% relative efficiency • N-type • Transistor reset type LN2 cooling ⇒Mechanical cooling ~6% photo peak efficiency @ 1 MeV from geant4 simulation Hyperball-J (half) 2007 JPS in Hokkaido University

  5. Hyperball-J design: “Wall-type” configuration • Wall-type • Large photo-peak efficiency • Compact detector size • Low cost of PWO crystal • Flexibility • Counting rate • Target and Inner detector • Experimental requirements Hyperball 1st 2007 JPS in Hokkaido University

  6. Hyperball-J design: “Wall-type” configuration • Wall-type • Large photo-peak efficiency • Compact detector size • Low cost of PWO crystal • Flexibility • Counting rate • Target and Inner detector • Experimental requirements Beam Hypernuclear g-ray spectroscopy mode Hyperball-J (half) 2007 JPS in Hokkaido University

  7. Hyperball-J design: “Wall-type” configuration • Wall-type • Large photo-peak efficiency • Compact detector size • Low cost of PWO crystal • Flexibility • Counting rate • Target and Inner detector • Experimental requirements Beam X atom X-ray spectroscopy mode Hyperball-J (half) 2007 JPS in Hokkaido University

  8. Hyperball-J design : Frame design Upper view As compact as possible 2007 JPS in Hokkaido University Driving parts Hyperball-J frame

  9. Mechanical cooler-Suppression for Radiation damage-

  10. Requirements on Hyperball-J Beam intensity J-PARC ~10.0 MHz K beam (w/ contamination p) KEK 2.0 MHz p beam Severe radiation damage (~1 month experiment is the limit for KEK) High counting rate at J-PARC Full model change of Hyperball !! • Mechanical cooler • PWO background suppressor • Waveform readout 2007 JPS in Hokkaido University

  11. Radiation damage • Energy resolution gets worse because the electron-hole pair is trapped by the damage of Ge crystal. • ~109 neutron/cm2 : Visible effects @ KEK • ~1010 neutorn/cm2 : Terrible effects @ J-PARC Effect of damage The effects can be suppressed by keeping the temperature ofGe crystal below ~85 K. ⇒Mechanical cooling LN2: >90 K Mechanical cooling : >75 K Energy resolution vs “Ge crystal Temperature” (damaged Ge) FWHM FWTM E. Hull and R. H. Pehlet al., IUCF Ann. Rep. 143, (1993) 2007 JPS in Hokkaido University

  12. ﾊﾞｯﾌｧﾀﾝｸ Mechanical cooler ｲﾅｰﾀﾝｽﾁｭｰﾌﾞ 提供 富士電機 ﾊﾟﾙｽﾁｭｰﾌﾞ • Requirements • Large cooling power • Low vibration • Compact size • Long term stability ⇒ Pulse tube refrigerator ｶﾞｽﾋﾟｽﾄﾝ 冷却端 蓄冷器 膨張機 圧縮機 ﾋﾟｽﾄﾝ Sterling cooler （Mechanical piston） Pulse tube cooler （Gas piston） ﾊﾟﾙｽﾁｭｰﾌﾞ 蓄冷器 圧縮機 放熱機 膨脹機 圧縮機 放熱機 蓄冷器 膨脹機 ｶﾞｽﾋﾟｽﾄﾝ ｲﾅｰﾀﾝｽﾁｭｰﾌﾞ ﾊﾞｯﾌｧﾀﾝｸ Conventional Ge detector + Refrigerator ⇒How to achieve those requirements ? 2007 JPS in Hokkaido University

  13. Mechanical cooler Phase shifter (Buffer tank, inertance tube) Pulse Tube 提供 富士電機 • Requirements • Large cooling power • Low vibration • Compact size • Long term stability ⇒ Pulse tube refrigerator Pressure wave generator (sterling) Regenerator Sterling cooler （Mechanical piston） Pulse tube coller （Gas piston） ﾊﾟﾙｽﾁｭｰﾌﾞ 蓄冷器 圧縮機 放熱機 膨脹機 圧縮機 放熱機 蓄冷器 膨脹機 ｶﾞｽﾋﾟｽﾄﾝ ｲﾅｰﾀﾝｽﾁｭｰﾌﾞ ﾊﾞｯﾌｧﾀﾝｸ Conventional Ge detector + Refrigerator ⇒How to achieve those requirements ? 2007 JPS in Hokkaido University

  14. R&D Ge • Three difficulties • Electric noise • Insulation • Microphonic noise by mechanical vibration • Flexible joint • Cooling power • Small heat resistance • Water cooling Straight heat rod Flexible joint Insulation Pulse Tube Cold head Temperature of Ge crystal : ~76 K Energy resolution @ 60Co 1.3 MeV : 2.2 keV (FWHM) (2.1 keV @ cooler power off) Water cooling 2007 JPS in Hokkaido University

  15. Tohoku University, May 2007 Ge detector Electric power meter Mechanical cooler power supply DAQ PC Mechanical cooler 2007 JPS in Hokkaido University

  16. The first test… LN2 Mechanical cooler ~2 keV >10 keV 60Co 1.3 MeV g-ray energy [keV] g-ray energy [keV] 2007 JPS in Hokkaido University

  17. Energy resolution : LN2 60Co 2.1 keV Pulser g-ray energy [keV] 2007 JPS in Hokkaido University

  18. Energy resolution : Mechanical cooler 60Co 2.2 keV Pulser g-ray energy [keV] 2007 JPS in Hokkaido University

  19. Final design The first Ge detector will be delivered in October. 13 cm Cooler ~110 cm Ge In-line mechanical cooler Water-cooling （regenerator, compressor） 2007 JPS in Hokkaido University

  20. Summary • Hyperball-J • Wall-type configuration • Position-adjustable frame designed • Mechanical cooling • Suppression of severe radiation damage at J-PARC • Required Ge crystal temperature (<85 K) and energy resolution (~2 keV) achieved • The first Ge detector delivery in October 2007 JPS in Hokkaido University

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