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 for neutron detector
(2) Baryon femtoscopy matrix
only tracking ---photon------neutron--
(13) (13)
photon + neutron (4)
photon or neutron (5) p Λ -  0 0 + n - X XX
X+X
(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 of Tn= 1 GeV
εn ~60% for neutrons of Tn= 0.2 GeV
400 photomultipliers/n(!) !

4. Neutron detectors(2) ELENS Neutron energy range of 100 keV to 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 ]

7. 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 module leading
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.

8. Required features for new created detector
Neutron energy range of 3 MeV to 250 MeV
Time resolution ~ 300 psec
(For L~2m->accuracy for neutron momentum MeV/c)
Position resolution one order better than module size (~ 1 cm)
Modular structure of detector for corelation measurements
Module shape acceptable 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)

9. 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%

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

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

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

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

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

15. 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.

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

17. Dependence of maximum deviation protons from deposit energies
(neutron energy 150 MeV)
All selected events

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

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

20. Results of the simulations
Neutron energy, MeV 50
100
150
200
300
% selected events
18,8
18,0
17,4
17,6
18,2
mean deviation end of protons track, mm
1,2
4,7
9,5
14,9
24,3
maximum deviation protons, mm
5,7
25,3
50,2
80,2
90,0

21. Next step

22. 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.

23. AA-view
Search for and study of cold dense baryonic matter
( Letter of intent )
 I.G.Alexeeev1, А.А.Gоlubev1, V.S.Goryachev1, А.G.Dolgolenko1, N.М.Zhigareva1, Yu.M.Zaitsev1, К.R.Мikhailov1, М.S.Prokudin1, М.I.Кatz1, B.О.Кеrbikov1, S.М.Кiselev1, N.А.Pivnyuk1, P.А.Polozov1, D.V.Romanov1, D.N.Svirida1, А.V.Stavinskiy1, V.L.Stolin1, G.B.Sharkov1 , А.Аndronenkov2, А.Ya. Berdnikov2 , Ya.А. Berdnikov2, М.А. Braun2, V.V. Vechernin2, L. Vinogradov2, V. Gerebchevskiy2, S. Igolkin2, А.Е. Ivanov2, V.Т. Кim3,2, А. Коlоyvar2, V.Коndrat’ev2, V.А.Мurzin3, V.А. Оreshkin3, D.P. Suetin2 ,G. Feofilov2,А.А.Bаldin4, V.S.Batovskaya4, Yu.Т. Borzunov4, А.V. Кulikov4,А.V. Коnstantinov4, L.V.Маlinina4,G.V.Mesheryakov4,A.P.Nagaitsev4, V.K. Rodionov4, S.S.Shimanskiy4, O.Yu.Shevchenko4
1). SSC RF ITEP , Моscow, 2). SPbSU, S.Peterburg, 3). SSC RF PINF, S.Peterburg, 4). LPHE,JINR,Dubna 6m T
beam A A

24. 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 of Tn=300MeV
2 neutrons in 1 module register like 1 neutron
Position resolution – module size
1.scintillator 2.lightguide
3.photomultipliers 4.photodiodes
5. voltage divider
6.magnetic screen 7. spring