UC Berkeley

In this work, the feasibility of utilizing a new generation of pulse shape discriminating plastic scintillators as structural materials is evaluated. The capacity to employ radiation detectors in structural roles provides potential advantages in mass-constrained and volume-constrained systems. This technology is particularly applicable to mobile-platform deployed detection payloads in which layouts can be augmented either by the addition of radiation detectors into currently incompatible placements and orientations, or through the replacement of inert structural mass by active-volume structural detector components. Additionally, the development of such materials enables the construction of payload-less radiation-detecting small unmanned aerial systems (sUASs), allowing for the miniaturization and consequent reduction of minimum source-detector measurement distances beyond currently achievable means.This work describes the design, construction, and evaluation of a payload-less radiation-mapping sUAS, originating with the development of novel PSD plastic scintillators suitable for use in the intended structural application. A comprehensive study of the PSD and mechanical properties of novel scintillator compositions, in collaboration with Lawrence Livermore National Laboratory, is described. Detector design is accomplished by simulation of complex active-volume sUAS frame geometries in GEANT4 optimizing light collection efficiency and detection efficiency, followed by experimental validation. Following computational modeling of optimal structural detector geometries, experimental active-volume sUAS frames were fabricated from which complete sUAS prototypes were constructed demonstrating semi-autonomous flight capability and onboard PSD spectroscopy. A series of prototypes was constructed, initially to prove structural feasibility in a 19 inches diameter, 2kg mass configuration, and subsequently improved upon to demonstrate PSD capability. The end result is the construction of a radiation-detecting sUAS constructed of four PSD plastic active-volume frame arms, with an overall diameter of 12 inches and approximately 1kg system dry mass. Proximity radiation mapping performance of the constructed systems was evaluated in γ-ray and neutron source localization field tests.