1. Development of neutron detector using GEM Beam Test Osaka City University M1 Nakagawa Shinsuke KEK 測定器開発室 阪市大理、ＫＥＫ A 、東大理 B 、信州大理 C 、 佐賀大理工 D 、東理大理工 E 中川真介、氏家宣彦 A 、内田智久 B 、宇野彰二 A 、大下英敏 C 、門松宏治 D 、杉山 晃 D 、杉山史 憲 E 、関本美知子 A 、田中秀治 A 、田中真伸 A 、 中野英一、仲吉一男 A 、村上 武 A

2. Experimental facility MUSASI 、 Japan Atomic Energy Agency JRR3 Guide hall beam Line (thermal neutron ） –collaborator Suzuki, Oku NOP 、 Japan Atomic Energy Agency JRR3 Guide hall beam Line (cool neutron ） –collaborator Suzuki, Oku Shinohara MINE 、 Japan Atomic Energy Agency JRR3 Guide hall beam Line (cool neutron ） –collaborator Hino, Hayashida KENS 、 KEK Neutron Science Laboratory –collaborator Sato 、 Ino 、 Shikauchi 、 Kamiyama

3. MUSASI & NOP test item MUSASI –beam profile ＆ image data –Detection Efficiency (comparison with 3 He counter) –uniformly 17mm pitch 5x5 mesh –Laue spot (monocrystal) NOP –position resolution –Test for Focusing Small- Angle Neutron Scattering ＢｅａｍＭＵＳＡ ＳＩ ＮＯＰ Wave length monochro me 2.24 Å ~8 Å Rate10 5 Hz/cm 2 10 3 Hz Beam size 5cm×2cm~2mmx~2 mm

4. Setup Converter –8 Boron-coated GEMs Thickness of a polyimide layer = 50 um Boron –Both sides coated –Thickness = 0.6μm x 2 Amplification –Single 100μm thick GEM Readout board –Strip lines (1.6 mm pitch )

5. Readout System Belle-CDC Pre-amp. Belle-CDC Pre-amp. ×7 RPN220×7 30 m 5 m RPN220Dscr. Gate Gen. 4ms delay Width 40ms ADC 2249A×9 ADC Gate CCNET busy IN FANIN/FANOUT Gate Gen.

6. Beam profile at MUSASI

7. Detection Efficiency 1mm φ Pin Hole (Cd plate) Detection Efficiency –24.0% (MUSASI) with 8 GEM foils Boron-10 : 0.6  m t both side  1.2  m t per one GEM foil –63% (NOP) with 8 GEM foils Boron-10 : 0.6  m t both side  1.2  m t per one GEM foil

8. Distortion of Detection position No Distortion XY direction 16mm pitch

9. Uniformly ( Detection Efficiency ) 1.000.981.031.020.99 0.970.990.981.020.98 0.991.00 0.98 0.971.011.001.010.98 1.001.051.031.020.98 Normalized to the detector center.

10. monocrystal K 2 SeO 4 22 ~40° ~90° λ ＝ 2.2 Å Neutron Beam Sample

11. monocrystal NaCl 2  = 38°(1,1,1) 2  = 50°(0,0,2) 2  = 76°(0,2,2)2  = 90°(1,1,3) λ ＝ 2.2 Å

12. Position resolution 1D Liner scale Strip pitch : 1.6mm 2D Log scale with 0.5mm  pin hole

13. Focusing Small-Angle Neutron Scattering sample:SiO 2 Hypresica Background Direct Beam HPS 500nm HPS 200nm

14. Conclusion (MUSASI&NOP) No distortion can be seen Uniformly ( detection efficiency ) Good image detector Good result for Focusing Small-Angle (Wide-Angle) Neutron Scattering

15. MINE beam –wave length ： ~8Å –Rate ： 1kHz 、 –Beam size ： 4mm (H)x40mm (V) Test for Neutron Resonance Spin Echo

16. The necessity for Neutron Resonance Spin Echo neutron Inelastic scattering –The space structure and energy changes state 中性子の波長分布が広い場合 入射中性子（グレーの部分） 散乱中性子 非弾性散乱 （青の部分） 非弾性散乱 （青の部分） 中性子の波長分布が狭い場合 非弾性散乱の差が微小な場合 散乱中性子 入射中性子（グレーの部分） 非弾性散乱 （青の部分） 非弾性散乱 （青の部分） 強度

17. Beam detector Setup (MINE)

18. Readout System Belle-CDC Pre-amp. Belle-CDC Pre-amp. ×7 RPN220×7 30 m 5 m RPN220Dscr. Gate Gen. 4ms delay Width 40ms ADC 2249A×9 ADC TDC Gate CCNET VETO busy IN FANIN/FANOUT Gate Gen. NIM-TTL Level Converter from MINE Dis ｃ ri TDC STOP

19. Setup Converter –1 Boron-coated GEMs Thickness of a polyimide layer = 50 um Boron –Both sides coated –Thickness = 1.2μm + 0.9μm Amplification –Single 100μm thick GEM Readout board –Strip lines (1.6 mm pitch)

20. Event=76835/50s 3 He counter 1536.7/s B-GEM Event=28704/100s 287.04/s 287.04/1536.7=0.1868 18.7% efficiency of Ｂ－ＧＥＭ chamber compare with 3 He counter B-GEM v.s. 3 He counter MUSASI 24 ％ (Eight sheets 、 2.24 Å、 1.2μ ）、 24%×1/8×8/2.24×2.1/1.2=18.75 ％

21. PNSE ： 0.670±0.014 freq. ： 1.7060±0.0006μsec PNSE ： 0.650±0.007 freq. ： 1.6700±0.0004μsec Ｂ－ＧＥＭ chamber Li scintillater ＋ ＰＭＴ (R3292) black red Timing resolution test at MINE Time (20nsec/bin) Normalized Hit Counts

22. Conclusion (MINE) A comparable as the performance of the existing detector. better timing resolution (comparison with Snci. + PMT) lower cost (comparison with Snci. + PMT)

23. KENS beam –White –Rate 20 Hz –Accelerator type test items –2D image Time development with powdery Diamond Laue spot (K 2 SeO 4 )

24. Experiment result KENS collaborator –Sato 、 Ino 、 Shikauchi 、 Kamiyama （ KEK Institute of Material Structure Science ） KENS neutron beam line

25. Readout System Belle-CDC Pre-amp. Belle-CDC Pre-amp. ×7 RPN220×7 30 m 5 m RPN220Dscr. T0 timing Fanin-Fanout Gate Gen. Coincidence 4ms delay Width 40ms CCNET GATE BUSY Gate Gen. GATE 120μs delay VETO Gate Gen. ADC 2249A×9 GATE Scaler CAMAC Trg. Gate Gated trg. CLK Gen. ( １ MH ｚ） 1s1s Reset

26. Signal waveform と Timing Signal waveform T0 SIGNAL GATE 4msec-44msec 200nsec

27. Diffraction image （ Powdery Diamond ） 3 He counter chamber sample Powdery Diamond Cd slit Beam 22

28. Powdery Diamond slide show 1frame/0.5ms from 4ms to21ms Remove Cd slit Time development of Diffraction Pattern 83mm flight time (wave length ） msec wave length spectrum 3 He are acquired by the existing system. Diamond Powder Pattern Simulation L=26m 2  =70deg. by Kamiyama

29. Time development with Powdery Diamond Diffraction Pattern

64. sample monocrystal K 2 SeO 4 Drift plane 1mm Al board Cd plate × ２ （ 5mm x 5mm ） Cd plate neutron beam 14mm GEM1 Potentials of Al-board and Drift plane are equal. sample

65. Simulation L=26m 2  =65deg. monocrystal K 2 SeO 4 Laue spot flight time (wave length) msec count/0.1msec 83mm by Kamiyama

66. Conclusion (KENS) Useful for J-PARC experiment –Laue spot & time development (by 2D imaging)

67. Conclusion GEM is useful as a neutron detector. Good image detector