1. Detection of neutrons in CB and TAPS
Reactions with neutrons
Identification of neutrons
Energy and angular resolutions
Detection efficiency
Applications
Summary
V.L.Kashevarov
V.L.Kashevarov, Collaboration Meeting, Glasgow 2006

2. Reactions with neutrons
g p → p+ n
g p → p+ po n
g d → p n

3. Identification of charged particles in CB
Cluster energy – PID energy.

4. CB calibration for p+ Q = 20˚ – 30˚ or 150˚ – 160˚
Fit function: E = a + bx + cx2 + dx3

5. Identification of g p → p+ n reaction
PID-Tagger time (ns)
fp-fn -180˚
MM(g,p) (MeV)

6. Identification of g p → p+ po n reaction
Eg – Epo < 450 MeV
PID-Tagger time (ns)
q12 (deg)
MM(g,p) (MeV)

7. Identification of g d → p n reaction

8. Neutrons in TAPS Veto detectors PSA Time of flight
Long gate vs short gate
PID-TAPS time (ns)

9. Veto efficiency map

10. Veto efficiency
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> % % %
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> % % %

11. Additional cut for protons in TAPS
Energy(ToF) – Energy(Cluster energy) (MeV)

12. Energy calibration for neutrons in TAPS
E=m / sqrt( 1 – (d/((t+dt)c))2 ) – m
Red curve: d = dt = 0.95
Blue curve: d = dt = 0.48
Green curve: d = dt = 0
g p → p+ n
g p → p+ p0 n
Energy (MeV)
Time of flight (ns)

13. Energy and angular resolutions for neutrons in TAPS
DE/Ecalc (%) DE vs Ecalc (MeV) DQ (deg) Df (deg)

14. Identification of neutrons in CB
Cluster energy
Cluster size
Time of flight
Cluster energy vs cluster size Time (ns)

15. Energy calibration for neutrons in CB
g p → p+ n
Energy (MeV)
Time (ns)

16. Energy and angular resolutions for neutrons in CB
DE vs Ecalc (MeV) DQ (deg) Df (deg)

17. Detection efficiency g p → p+ po n
Tresholds for cluster: 5, 10 and 20 MeV
Efficiency Counts
Neutron energy (MeV)

18. g p → p+ n g

19. g d → p0 p n g
MM(g,p0) (MeV)

20. Summary
Identification of neutrons in CB is possible and sometimes useful;
need MC simulation to check neutron identification method and determine experimental resolutions for neutrons in wide energy region;
need additional cut for protons which are detected as neutrons in TAPS.