1. Development of position sensitive neutron detectors Chernishov O.A., Goryachev V.S., 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. (ITEP,Moscow) Dubna 2014 1

2. Motivation 2 1.Neutron is one of the main particle specie for AA collision at Nuclotron-NICA energy range; 2.State of nuclear matter depends on n/p ratio; 3.To identify some strange particles one need identify neutrons (for example  +  n  + ); 4.Femtoscopy measurements: space time parameters for np and pp, nn are different. ___________________________________  Need to measure neutrons Accuracy and kinetic energy range? Temperature of the order of 100 MeV =>Energy range for neutron Ekin~ 10 – 200MeV Femtoscopy : the width of the effect ~30MeV/c =>  p~10 MeV/c, cross-talk problem

3. If the same neutron is registered in two or more detectors – the cross-talk effect occurs. It simulates registration of two or more neutrons in neighbor modules  to a strong false correlation. In case of single particle measurements the cross-talk effects are usually small, but in femtoscopy measurements this effect is quite important and dangerous. Cross-Talks problem 3 Solution: position sensitive detector

4. Required features for new created detector Neutron energy range of 10 MeV to 200 MeV Accuracy for neutron momentum 10-20 MeV/c Modular structure of detector for corelation measurements Compact installation modules to create large acceptance detector Position resolution one order better than module size (about 1 cm) Compact module

5. 5 Neutron detector (prototype 1)-ITEP Plastic Scintillator 96 * 96 * 128 mm 3 Fiber: KYRARAY,Y-11,d =1mm, wavelength shift 4 SiPM & Amplifier - CPTA(Golovin) Efficiency (estimate) 15%

6. Tests of prototype 1 with proton beam(ITEP) PC1 Beam of Protons p=3GeV/c PC2 Ndet 6

7. Tests of prototype 1 with neutron beam (MARUSYA) Neutron near 2 diode Neutron near 4 diode

8. 8 Neutron detector (prototype 1) d (cm) R=A 4 /A 2 spatial resolution for the first prototype ~ 2.5 cm

9. Fiber + SiPM 15 cm Distance from the target 240cm; Detector thickness 20cm Neutron detector for MARUSYA-FLINT Stage 1(7modules) Stage 2(19modules) Next step to improve spatial resolution from 2,5 to 1,5 cm. Prototype1 4 diodes * 1 mm 2 Prototype2 6 diodes * 4 mm 2

10. 10 Front Side Back Neutron detector (prototype 2)-ITEP During the assembling

11. 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). 10 5 neutrons for each energy. Neutrons shoot to detector centre. Event selection criteria: one proton realize after first interaction. 11 Principal restriction for neutron coordinate resolution Green track – neutron Red - proton Blue - electron

12. Distribution of secondary protons in the transverse coordinates 150MeV300MeV 12 Simulation neutron detector (prototype 2)-ITEP

13. 13 All selected events Dependence of maximum deviation protons from deposit energies (neutron energy 150 MeV) Green track – neutron Red - proton Blue - electron

14. 14 Neutron energy, MeV 50100150200300 mean deviation of protons track, mm 0,62,44,87,512,2 Results of the simulations

15. Amplitude spectrum for prototype 2  =0,056

16. Next step – prototype 3 photomultiplier veto

17. Conclusions 1. The prototype 1 was designed, constructed and tested. Beam tests was made at ITEP(2011) and JINR(2012-2013). 2. The results of beam tests was used in simulations of the prototype 2. 3. All characteristics of the prototype 2, obtained from this simulations, are in accordance with designed goals. 4. Prototype 2 is constructed and ready for the beam test at Nuclotron (MARUSYA)

18. pΛ -- 00 00 ++ n -- pXXXXXXXXX ΛXXXXXXXX -- XXXXXXX  XXXXXX 00 XXXX+XX+XX+XX+X 00 XXX+XX+XX+XX+X ++XXX nXX -- X -----track----------- ----photon------neutron-- 10 18(13) 18(13) photon+neutron (4) photon or neutron (5) Femtoscopy baryon matrix Physical need to create neutron detector 18

19. LANS(LINP-1980) large acceptance neutron spectrometer V.N.Baturin et al., LINP-594,1980V(L x L y L z )=200x200x1000mm 3 σ τ =2nsec ε n =35% for neutrons of T n =300MeV 2 neutrons in 1 module register like 1 neutron Position resolution – module size Neutron detectors(1) 19 1.scintillator 2.lightguide 3.photomultipliers 4.photodiodes 5. voltage divider 6.magnetic screen 7. spring

20. 20 Neutron detectors(2) LAND Large area detector for high-energy neutrons ΔT n /T n = 5.3% for neutrons of T n = 1 GeV angular resolution: 0.2° for a flight path of 15 m ε n ~100% for neutrons of T n = 1 GeV ε n ~60% for neutrons of T n = 0.2 GeV 400 photomultipliers !

21. ε n =20-30% for neutrons of Tn=60-250MeV Time resolution ~ 250psec Liquid scintillator Divide signals by form Large total volume V ~ 50 dm 3 and small sensitive volume V ~ 4 dm 3 [Tilquin I. et al., Nucl. Instrum. Methods A365, 1995, p.446 ] 21 Neutron detectors

22. Beam tests of prototype 1 DC1 Beam of Protons p=3GeV/c DC2 Ndet 22 Amplitude spectrum

23. ELENS Neutron energy range of 100 keV to 10 MeV angular resolution of less than 1 degree ε n =25% for neutrons of Tn=500 keV ε n =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 23 Neutron detectors(3)

24. 24 Neutron Beam test of prototype2@Nuclotron Calibration on neutrons

25. 25 Back wall events and collision with nucleus events Dependence of maximum deviation protons from deposit energies

26. 26 Main events Dependence of maximum deviation protons from deposit energies

27. 27 Neutron energy, MeV 50100150200300 % selected events 18,818,017,417,618,2 mean deviation of protons track, mm 0,62,44,87,512,2 maximum deviation protons, mm 5,725,350,280,290,0 Results of the simulations

28. 0 Hexagon cube 96x96 cube 200x200

29. Purpose of simulation – estimation difference between neutron coordinate and recoil proton coordinate. In framework Geant4 n+detector interaction for different neutron energy was simulated. C/H ~ BC400. 10 5 neutrons for each energy. Neutrons shoot to detector centre. Event selection criteria: one proton realize after first interaction. Энергия, МэВ50100150200300 % отобранных событий 18,818,017,417,618,2 RMS х1.24.89.915.424.7 RMS у1.24.99.915.724.8 29 Principal restriction for neutron coordinate resolution

30. Cross-Talks 30 Displace modules for solution cross-talk effect

31. 31 Neutron detector (first prototype)-ITEP

32. A A AA-view 6m beam T Search for and study of cold dense baryonic matter ( Letter of intent ) I.G.Alexeeev 1, А.А.Gоlubev 1, V.S.Goryachev 1, А.G.Dolgolenko 1, N.М.Zhigareva 1, Yu.M.Zaitsev 1, К.R.Мikhailov 1, М.S.Prokudin 1, М.I.Кatz 1, B.О.Кеrbikov 1, S.М.Кiselev 1, N.А.Pivnyuk 1, P.А.Polozov 1, D.V.Romanov 1, D.N.Svirida 1, А.V.Stavinskiy 1, V.L.Stolin 1, G.B.Sharkov 1, А.Аndronenkov 2, А.Ya. Berdnikov 2, Ya.А. Berdnikov 2, М.А. Braun 2, V.V. Vechernin 2, L. Vinogradov 2, V. Gerebchevskiy 2, S. Igolkin 2, А.Е. Ivanov 2, V.Т. Кim 3,2, А. Коlоyvar 2, V.Коndrat’ev 2, V.А.Мurzin 3, V.А. Оreshkin 3, D.P. Suetin 2,G. Feofilov 2,А.А.Bаldin 4, V.S.Batovskaya 4, Yu.Т. Borzunov 4, А.V. Кulikov 4,А.V. Коnstantinov 4, L.V.Маlinina 4,G.V.Mesheryakov 4,A.P.Nagaitsev 4, V.K. Rodionov 4, S.S.Shimanskiy 4, O.Yu.Shevchenko 4 1). SSC RF ITEP, Моscow, 2). SPbSU, S.Peterburg, 3). SSC RF PINF, S.Peterburg, 4). LPHE,JINR,Dubna 32 Neutron detector (second prototype)-ITEP

33. 1.Протоны вылетевшие через заднюю стенку детектора. 2.Протоны столкнувшиеся с ядрами. 3.Все отобранные события без первых двух 4. Все отобранные события. 1 2 3 4 33 Simulation neutron detector (second prototype)-ITEP

34. 34 Разделение событий Все отобранные события Протоны вылетевшие через заднюю стенку Протоны столкнувшиес я с ядрами. Линия основных событийДругие события

35. 35 Разделение событий Все отобранные события Протоны вылетевшие через заднюю стенку Протоны столкнувшиес я с ядрами. Линия основных событийДругие события

36. Trajectories of the particles inside the detector. Green line - neutron trajectory, red - proton. 36 Simulation neutron detector (second prototype)-ITEP view of the model