Front-End Design for SiPM-Based Monolithic Neutron Double Scatter Imagers

• Main Authors: Balajthy, J. (Author), Brubaker, E. (Author), Cates, J.W (Author), Hausladen, P. (Author), Negut, V. (Author), Steele, J. (Author), Ziock, K. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: Cameras; Coincidence detection; Detection efficiency; Efficiency; monolithic scintillation detector; Monolithic scintillation detector; Monolithics; neutron double scatter imaging; Neutron double scatter imaging; neutron imaging; Neutron imaging; Neutron sources; Neutrons; Organic scintillator; Particle beams; Photomultipliers; Photons; Photosensitivity; Scatter imaging; Scintillation counters; Silicon; Silicon photo multipliers (SiPM); silicon photomultipliers; Single photons
• Online Access: View Fulltext in Publisher

 Neutron double scatter imaging exploits the kinematics of neutron elastic scattering to enable emission imaging of neutron sources. Due to the relatively low coincidence detection efficiency of fast neutrons in organic scintillator arrays, imaging efficiency for double scatter cameras can also be low. One method to realize significant gains in neutron coincidence detection efficiency is to develop neutron double scatter detectors which employ monolithic blocks of organic scintillator, instrumented with photosensor arrays on multiple faces to enable 3D position and multi-interaction time pickoff. Silicon photomultipliers (SiPMs) have several advantageous characteristics for this approach, including high photon detection efficiency (PDE), good single photon time resolution (SPTR), high gain that translates to single photon counting capabilities, and ability to be tiled into large arrays with high packing fraction and photosensitive area fill factor. However, they also have a tradeoff in high uncorrelated and correlated noise rates (dark counts from thermionic emissions and optical photon crosstalk generated during avalanche) which may complicate event positioning algorithms. We have evaluated the noise characteristics and SPTR of Hamamatsu S13360-6075 SiPMs with low noise, fast electronic readout for integration into a monolithic neutron scatter camera prototype. The sensors and electronic readout were implemented in a small-scale prototype detector in order to estimate expected noise performance for a monolithic neutron scatter camera and perform proof-of-concept measurements for scintillation photon counting and three-dimensional event positioning. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.