Which is better, a SCoTSS gamma imager, or an ARDUO UAV-borne directional detector?

TL;DR

This paper compares the capabilities of the SCoTSS gamma imager, which produces images of radioactive sources, and the ARDUO UAV-borne detector, which offers directional detection without imaging, to evaluate their effectiveness in mobile radiation surveys.

Contribution

The study provides a comparative analysis of imaging versus directional detection methods for mobile gamma radiation surveys, highlighting their respective advantages and limitations.

Findings

SCoTSS can produce detailed gamma source images.

ARDUO offers effective directional detection with a close-packed crystal design.

Both systems are suitable for different types of mobile radiation mapping tasks.

Abstract

The SiPM-based Compton Telescope for Safety and Security (SCoTSS) has been developed with inorganic crystalline scintillator material for gamma detection. The instrument is sensitive enough to be used in a mobile survey mode, accumulating energy deposited in any crystal second-by-second and tagging these spectra with GPS position. The SCoTSS imager of course has the additional advantage of being able to produce an image of the radioactive objects in its field of view using events that satisfy a coincidence trigger between the scatter and absorber layers. The Advanced Radiation Detector for UAV Operations (ARDUO) on the other hand, is a non-imaging directional detector intended for use aboard a small unmanned aerial vehicle (UAV). The ARDUO detector features exactly the same volume of CsI(Tl) as is used in the absorber layer of a single SCoTSS module, giving it similar detection and alarming sensitivity, and map-making capability. However, in the ARDUO detector, the crystals are arranged closely together to optimize direction determination from self-shielding effects. Flown in a grid pattern with a UAV over an area of extended contamination, the ARDUO detector is also capable of making a map or image of that area. With its close-packed crystal arrangement, the ARDUO detector makes a poor Compton imager but does have some ability to produce a peripheral image in a fly-by. In this presentation we investigate the relative merits of Compton imaging versus mobile directional detection.