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Neutron position sensitive detector

Neutron position sensitive detector

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Neutron position sensitive detector

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  1. Neutron position sensitive detector ITEP,Moscow Goryachev V.S., Chernishov O.A., Kirin D.Yu., Mikhailov K.R.,Polozov P.A., Prokudin M.S., Romanov D.V., Sharkov G.B., Stavinskiy A.V., Stolin V.L.,Zhigareva N.M. 1 Nantes 2014

  2. Physical motivation forneutron detector (2) Baryonfemtoscopy matrix only tracking ---photon------neutron-- 10 18(13)18(13) photon + neutron (4) photon or neutron (5) (1) Phase diagram for nuclear matter

  3. Neutron detectors(1) LAND Large area detector for high-energy neutrons ΔTn/Tn= 5.3% for neutrons of Tn= 1 GeV angular resolution: 0.2° for a flight path of 15 m εn ~100% for neutrons ofTn=1GeV εn ~60% for neutrons ofTn=0.2GeV 400 photomultipliers/n(!) !

  4. Neutron detectors(2) ELENS Neutron energy range of 100 keVto 10 MeV angular resolution of less than 1 degree εn =25% for neutrons of Tn=500 keV εn =40% for neutrons of Tn=1 MeV Flight path 1-2 m Time resolution 840 ps Position resolution ~7,5 сm Neutron energy is determined using ToF tecnique Very good light-collection efficiency is required for the detection of these small signals, so a proper wrapping material and the tight fitting of the foil onto the plastic were important criteria for ensuring a sufficiently high-quality light connection. Wrapping procedure let reduce energy threshold Foil (VM2000) has a good reflection coefficient of R > 97% for ≥ 400 nm and R = (98.5 ± 0.3)% at 430 nm

  5. Neutron detectors(3) εn =20-30% for neutrons of Tn=60-250MeV Time resolution ~ 250psec Liquid scintillator-> different signal shape for n/γ Large total volume V ~ 50 dm3 and small sensitive volume V ~ 4 dm3 [Tilquin I. et al., Nucl. Instrum. Methods A365, 1995,p.446 ]

  6. Cross-Talks Cross-Talks If the same neutron is registered in two or more detectors – the cross-talk effect occurs. Cross-talk: simulates registered of two or more neutrons in neighbor moduleleading to a strong spurious correlation. In case of one-particle distribution the cross-talk effects are usually small, but in femtoscopy measurements this effect is quite important and dangerous.

  7. Required features for new created detector Neutron energy range of 3MeV to 250 MeV Time resolution ~ 300 psec (For L~2m->accuracy for neutron momentum 15-25 MeV/c) Position resolution one order better than module size (~ 1 cm) Modular structure of detector for corelation measurements Module shapeacceptable for germetic installation -> to create germetic large acceptance detector Compact module(to be able to use it as a part of universal detectors within magnets)

  8. Neutron detector (first prototype)-ITEP Plastic Scintillator 96 * 96 * 128 mm3 Fiber: KYRARAY,Y-11,d =1mm, wavelength shift 4 SiPM & Amplifier - CPTA(Golovin) Efficiency (estimate) 15%

  9. Beam tests of first prototype Amplitude spectrum DC1 DC2 Beam of Protons p=3GeV/c Ndet

  10. Neutron detector (first prototype)-ITEP R=A4/A2 d (cm) space resolution for the first prototype ~ 2.5 cm

  11. Neutron detector (second prototype)-ITEP Distance from the target 240cm; Detector thickness 20cm Neutron detector supermodule (78 detectors) Fiber + SiPM 180cm 20cm

  12. Neutron detector (second prototype)-ITEP Front Side Back

  13. Neutron Beam test of prototype@Nuclotron Calibration of neutron detector Td= 4 GeV/nucleon 14

  14. Principal restriction for neutron coordinate resolution Purpose of simulation – estimation difference between neutron coordinate and recoil proton coordinate. In framework Geant4 n+detector interaction for different neutron energy was simulated. H/C ~ BC400 (1.103).105 neutrons for each energy. Neutrons shoot to detector centre. Event selection criteria: one proton realize after first interaction.

  15. Simulation neutron detector (second prototype)-ITEP 150MeV 300MeV Distribution of secondary protons

  16. Dependence of maximumdeviation protons from deposit energies (neutron energy 150 MeV) All selected events

  17. Dependence of maximumdeviation protons from deposit energies Back wall events and collision with nucleus events

  18. Dependence of maximumdeviation protons from deposit energies Main events

  19. Results of the simulations

  20. Next step

  21. Conclusions 1. Principal restriction for spatial resolution for detector < 1 cm at neutron energy < 150 MeV. 2. Expected spatial resolution for created module of detector less than 1,5cm.

  22. Neutron detectors(1) LANS(LINP-1980) large acceptance neutron spectrometer V.N.Baturin et al., LINP-594,1980 V(LxLyLz)=200x200x1000mm3 στ=2nsec εn =35% for neutrons ofTn=300MeV 2 neutrons in 1 module register like 1 neutron Position resolution – module size 1.scintillator2.lightguide 3.photomultipliers4.photodiodes 5. voltage divider 6.magnetic screen7. spring