164 research outputs found
Proof of principle of a high-spatial-resolution, resonant-response gamma-ray detector for Gamma Resonance Absorption in 14N
The development of a mm-spatial-resolution, resonant-response detector based
on a micrometric glass capillary array filled with liquid scintillator is
described. This detector was developed for Gamma Resonance Absorption (GRA) in
14N. GRA is an automatic-decision radiographic screening technique that
combines high radiation penetration (the probe is a 9.17 MeV gamma ray) with
very good sensitivity and specificity to nitrogenous explosives. Detailed
simulation of the detector response to electrons and protons generated by the
9.17 MeV gamma-rays was followed by a proof-of-principle experiment, using a
mixed gamma-ray and neutron source. Towards this, a prototype capillary
detector was assembled, including the associated filling and readout systems.
Simulations and experimental results indeed show that proton tracks are
distinguishable from electron tracks at relevant energies, on the basis of a
criterion that combines track length and light intensity per unit length.Comment: 18 pages, 16 figure
Time-resolved fast-neutron imaging with a pulse-counting image intensifier
A new imaging method that combines high-efficiency fast-neutron detection with sub-ns time resolution is presented. This is achieved by exploiting the high neutron detection efficiency of a thick scintillator and the fast timing capability and flexibility of light-pulse detection with a dedicated image intensifier. The neutron converter is a plastic scintillator slab or, alternatively, a scintillating fibre screen. The scintillator is optically coupled to a pulse counting image intensifier which measures the 2-dimensional position coordinates and the Time-Of-Flight (TOF) of each detected neutron with an intrinsic time resolution of less than 1 ns. Large-area imaging devices with high count rate capability can be obtained by lateral segmentation of the optical readout channels
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