Light collection in scintillation detector composites for neutron detection

The authors have been investigating the heterogeneous combination of neutron-conversion materials in a plastic or liquid scintillation matrix with the goal of developing neutron detectors of high detection efficiency and fast response. They report on one such combination, consisting of thin-wall glass microspheres filled with high-pressure /sup 3/He gas dispersed in plastic scintillation. They have developed glass formulations that are capable of containing the helium in shells with wall thickness as low as 1 mu m with leak rates at room temperature that correspond to several years half life. The energy loss of the reaction products in the shell wall and the low light yield of plastic scintillations for low-energy protons result in low light yield per event. The authors discuss the use of an optical modeling code to investigate the incorporation of wavelength-shifting elements to aid in the collection of this light from highly scattering composite scintillation media.<>