Improving thermal-neutron detection efficiency of silicon neutron detectors using the combined layers of 10B4C on 6LiF

Abstract We tested a layered structure of 10 B 4 C on 6 LiF ( 10 B 4 C/ 6 LiF) neutron converter for use with silicon neutron detectors. The combined layers effectively improve the efficiency of thermal-neutron detection over that of traditional single-layer converters. Silicon neutron detectors were constructed from a 2 cm × 2 cm silicon planar detector and coupled with removable neutron converters made from layers of 10 B 4 C, 6 LiF, or 10 B 4 C/ 6 LiF deposited on ceramics. The responses of these devices were tested with an 241 Am–Li neutron source and the accompanying background gamma rays. The capability of the devices to discriminate neutron events from background gamma rays was tested by varying the bias voltages of the detectors when irradiated with an 241 Am–Li neutron source and with 137 Cs or 60 Co gamma sources. The silicon neutron detector using the 10 B 4 C/ 6 LiF converter of 1.2- μ m-thick 10 B 4 C and 21.1- μ m-thick 6 LiF achieved the expected thermal-neutron detection efficiency of 5.6%. The compact size, simple construction, and low bias voltage of these devices make them promising for neutron detector applications like neutron dosimeters and beam monitors.