Development of neutron detector using the PIN photodiode with polyethylene (n,p) converter

A Si photodiode detector, PIN type, 10×10mm, with a slim film of a converter material, capable to produce charged particles, was used as sensor of neutrons and it was projected to he used in an environment of a zero power reactor. Polyethylene, n(CH₂), which produces recoil protons from the (n,p) interaction was used to improve the detection efficiency. The optimal thickness of the converters was determined experimentally and a mathematical model was applied to fit to the experimental data. For an AmBe source the optimum polyethylene layer thickness was of 0.0873 cm (94.3 mg.cm^-2). The converter of polyethylene was capable to improved the detection efficiency to a factor of 14.8 compared to measurements without converter. The detector shows a good response (r²=99.93%) to estimate the power variation during the operation of the zero power type reactor (IPEN/MB-01). Due to the high efficiency of the detector and its small size it is a good alternative to be used as a personal dosimeter.