Variant Designs and Characteristics of Improved Microstructured Solid-State Neutron Detectors

Perforated semiconductor neutron detectors are compact, high-efficiency, diode detectors that operate at low power. Microstructured neutron detector fabrication methods have been improved over previous manufacturing methods. The neutron detectors are easily fabricated from high purity n-type Si, in which patterned trenches are etched into the Si substrate, wherein shallow p-type junctions are diffused. The trenches are then backfilled with (LiF)-Li-6 powder, making the devices sensitive to reaction products from the Li-6(n,t)He-3 reaction. Pulse height spectra show improved signal-to-noise ratio, higher neutron counting efficiency, and excellent gamma-ray discrimination over previous microstructured neutron detector designs. Thermal neutron detection measurements from a 0.0253 eV diffracted neutron beam, yielded 20.4% intrinsic detection efficiency for devices with 245 micron deep trenches and 21% intrinsic detection efficiency for two back-to-back devices each having 113 micron deep trenches.