Enhanced high-sensitivity multi-layer neutron detector based on LiF:ZnS(Ag) scintillator.

This study proposes a novel, highly sensitive neutron detector design utilizing a unique multi-layered configuration. Each layer consists of a LiF: ZnS(Ag) scintillator coupled with a transparent neutron moderator that also functions as a light guide for the Silicon Photomultiplier (SiPM) light sensor. This design offers a cost-effective and readily available alternative for existing neutron detectors.

Cold neutron radiation dose effects on a LiF:ZnS(Ag) neutron detector with wavelength shifting fibers and SiPM photodetector.

A LiF:ZnS(Ag) based cold neutron detector with wavelength shifting (WLS) fibers and SiPM photodetector was developed at the NIST Center for Neutron Research for the CANDoR instrument (Chromatic Analysis Neutron Diffractometer or Reflectometer). A series of detectors were irradiated with neutron doses ranging between 1E+11 n/cm to 6E+12 n/cm. It was found that the neutron absorbing Li isotope was not measurably depleted, but the photonic yield of the detector deteriorated with increasing neutron dose.

LiF:ZnS(Ag) Neutron Detector Performance Optimized Using Waveform Recordings and ROC Curves.

We used Gaussian separation and receiver operating characteristic (ROC) curves to optimize the neutron sensitivity and gamma rejection of an ultra-thin LiF:ZnS(Ag)-scintillator-based neutron detector paired with a silicon photomultiplier (SiPM). We recorded the waveforms while operating the detector in a monochromatic cold neutron beam and in the presence of isotopic Cs and Co gamma sources. We used a two-window charge comparison (CC) pulse-shape discrimination (PSD) technique to distinguish the neutron capture events from other types of signals.

New detection configuration for low activity levels of PET tracers during the analysis of plasma samples.

A new radio-HPLC detection system for measuring radioactivity in plasma samples during Positron Emission Tomography [PET] studies was developed. It is based on detecting both the positron and one of the annihilation photons. The system focused on improving the measurement of radioactivity concentrations on an unmetabolized positron emitting a radiopharmaceutical [PER] in the presence of its radioactive metabolites, all containing the same positron emitter.

An energy analyzing detector for cold neutrons.

We describe the design, fabrication, and performance of an energy analyzing detector package for cold neutron spectrometers at the NIST Center for Neutron Research (NCNR). The detector package consists of arrays of highly oriented pyrolytic graphite crystals set at takeoff angles corresponding to different neutron energies. Neutrons incident down the array will be selected out by the appropriate crystal and directed onto an associated neutron detector.