Neutron Detection Setups proposed for

Transcription

1 Neutron Detection Setups proposed for DESPEC D. Cano-Ott on behalf of the WG members CIEMAT, IFIC, LNL, FYL, UPC, UU, UW

2 Motivation GOAL: to measure neutron emission probabilities and energies for neutron rich isotopes with relevance to basic nuclear physics and nuclear technology: -Low production: 4π detector -High production: TOF spectrometer (in combination with a gamma ray setup)

3 (I) TOF Neutron Spectrometer (NE213) First Monte Carlo simulations with GEANT4. First experimental tests with a commercial detector cell + digital electronics. 2R d L Neutron source Ion beam

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8 Bicron BC501A neutron detector + digital electronics BC501A (NE213) 12.7cmx12.7cm PMT: Hammamatsu R More than one scintillation decay component allow to discriminate between different exciting particles. Different response t = 3.16 ns, 32.3 ns & 270 ns to different particles i.e. specific energy losses (de/dx) e,p,a Pulse Shape Analysis with digital electronics (talk by C. Guerrero)

9 (II) Position Sensitive TOF Neutron Spectrometer (NE213) Possible 2 nd layer of detectors for enhancing the efficiency d H L Neutron source

10 (III) 4π4 Neutron Detector Polyethylene (60cm x 60cm x 80cm) NERO detector [1] Hendryk Schatz schatz@nscl.msu.edu Ring A 3 He prop. Counters Internal diam.:2.5 cm Length: 80 cm Pressure:4.1 bar Wall thickness:0.05 cm Ring B and C BF 3 prop. Counters (99% 10 B) Internal diam.: 5.08 cm Length: 80 cm Pressure: 0.7 bar Wall thickness:0.05 cm Hole (void) 22.4 cm diameter Boron Carbide layer 1 cm thickness

11 3 x BF 3 counters 3 x position sensitive 3 He counters 1 m3 of polyethylene 3x BF 3 counter (various sizes) 3x 3 He counter 5 cm x 50 cm

12 List of activities Monte Carlo simulations of the 2 types of TOF arrays (GEANT4) and the 4π detector (MCNPX) for the design of the prototypes/setups. First Monte Carlo simulation results for the TOF neutron spectrometer The Monte Carlo simulation tools have been setup up. A realistic geometry of the detectors has been modelled for the GEANT4 code. The efficiencies and energy resolutions of the two setups are in agreement with the initial estimates. First Monte Carlo simulation results for the 4π detector (talk by G. Cortés) A realistic geometry of the detectors has been modelled for the MCNP(X) code. The efficiency is in agreement with the initial estimates for the NERO detector

13 Hardware acquired for the prototyping phase 3 x BF 3 counters 3 x position sensitive 3He counters 1 m3 of polyethylene 1 x BC501A (NE213) scintillator from St. Gobain with low background housing (5 x 5 ) 1 additional module ordered from Scionix Computer driven CAEN HV Crate 2 HV cards with 10 channels each Men power (At least) 3 predoctoral positions open for the development of neutron detectors (CIEMAT, IFIC, UPC ) Test measurements Testbench at CIEMAT. Calibration of the BC501A with γ-ray sources and a weak Am/Be source. Test of pulse shape analysis algorithms (already used at n_tof) and digital electronics. Calibration of the BC501A module with a D/T source in Grenoble. Validation of the simulation tools. Test of the 3 He and BF 3 modules with an Am/Be source at the Universidad Politécnica de Madrid.

14 Next steps Definition of the DESPEC physics case(s). Training of people: -GEANT4 course in Spain (to be scheduled) -Test measurements at different facilities. Where? Participation in ongoing experiments, beam time requests? Development of appropriate simulation tools (GEANT4 and/or other codes) Programming of realistic event generators (talks by D. Jordan and J.L. Taín) Inclusion of the light production for different particles: L(E dep ) Modelling of the correct physics processes: neutron capture (γ-ray production), neutron inelastic reactions Identify and model all possible sources of background. Cross talk with other setups: geometry database. Validation and benchmark of the simulations

15 Design, construction and testing of prototypes Test and characterise different materials at different neutron energies. Where? Test different digital electronics: various combinations of sampling rates (up to 1 GSample/s) and resolutions (8 14 bits). Industry but also R&D electronics. Develop and test appropriate Pulse Shape Analysis algorithms. Perform measurements under simple experimental conditions: well studied cases, simple geometry, optimal signal to noise ratios. Where?

16 Monte Carlo simulations TOF 4π detector Model the proper physics in the different codes: -Light Output and collection γ-ray production in neutron interactions (capture, inelastic ) Write realistic event generators. Identify and simulate the sources of background: time correlated γ- rays, uncorrelated events, ambient background, impurities in the beam. Cross talk with other setups: implantation, but also others like Ge-array. Goal: define the optimal geometries after simulating a realistic experiment

17 Design, build and perform test measurements with prototypes TOF 4π detector Test different materials/detectors at various neutron energies (which facilities). Test different digital electronics: various combinations of sampling rates (up to 1 GSample/s) and resolutions (8 14 bits). Industry but also R&D electronics. Develop and test appropriate Pulse Shape Analysis algorithms. Perform measurements under simple experimental conditions: well studied cases, simple geometry, optimal signal to noise ratios (facilities). Compare and validate the Monte Carlo simulations. Goal: decide the materials and geometry of the final detectors