Application of CR-39 Track Detector to Neutron Spectrum Measurement

Abstract

A new technique for estimating the neutron energy spectrum with CR-39 track detectors has been proposed for application to a singly pulsed neutron field where prevailing counters cannot operate properly. The CR-39 sample exposed to neutrons was intermittently etched, then the major and minor radii of respective etch pits were measured for each etching stage and the growth curve was obtained. The analysis method of growth curves was also designed, with which both the energy and the angle of recoil protons could be evaluated and converted into the energy of neutrons incident normally.The neutron irradiation experiments were carried out with the 46 MeV electron linear accelerator at the Research Reactor Institute, Kyoto University. It was confirmed from comparing with the reference spectrum measured by the neutron time-of-flight method that the present growth-curve method is useful for the estimation of the neutron energy distribution between about 0.3 and 2 MeV. Moreover, we have experimentally examined the unfolding method suggested by Matiullah and Durrani in order to extend the application of CR-39 detector to higher energies.

Demonstration of laser-produced neutron diagnostic by radiative capture gamma-rays

“…Several techniques have been adopted to diagnose fast pulsed neutrons, including neutron active analysis [23], neutron track detector [24], thermal neutron gas counter [25], along with neutron TOF [26], etc. In neutron active analysis, foils made from silver, indium, or copper are commonly employed for absolute neutron dosimetry [27].…”

Measurement of neutron spectra generated from bombardment of 4 to 24 MeV protons on a thick 9Be target and estimation of neutron yields

“…In addition, these measurements (except time of flight) involve complex spectrum unfolding procedures using codes like MAXED, 15 ANDI-03, 16 FRUIT, 17 BUNKI, 18 GAMCD, 19 LOUHI, 20 etc., to generate the neutron spectrum which further require a well-defined response matrix and initial guess spectrum. [21][22][23] Considering this difficult instrumentation, time consuming analysis, and complex unfolding procedures, the passive technique using CR-39 detectors and image analysis programs as an alternative for neutron spectrometry has gained popularity in the recent past. 24 Researchers have developed response matrices for Bonner Sphere Spectrometry using boron coated CR-39 detectors 25 with experimental validation.…”