Issue link: https://htpgraphics.uberflip.com/i/1385717
RAIN PROGRESS // Regardless of the shape, size, or scintillator material, the readout and data processing electronics remain largely the same in each application. RAIN researchers at Bristol University have taken advantage of this opportunity by designing a modular scintillator detector that allows easy swapping of crystals and SiPMs (Silicon photomultipliers) to fit nearly any application. A comprehensive survey provided input data to guide the design criteria. It remains of critical importance to match scintillator peak emission wavelength to the sensitivity spectrum of a specific SiPM to maximise the signal yield. However once the wavelength match is established, the crystal and matching SiPM can be plugged into standardised signal processing electronics. The electronic signal processing path is currently under development at Bristol University, and the first prototypes have already been lab tested. It consists of an analog front-end with a pulse shaping amplifier, a fast ADC (Analog-to-Digital Converter) to digitise pulses, and an FPGA to analyse data and implement a dynamic peak fitting algorithm to take advantage of true hardware acceleration. UNIQUENESS // In terms of solid-state gamma radiation detectors, solid scintillator crystals offer the most flexibility to design gamma radiation detectors to specific requirements. Although scintillators don't get anywhere near the energy resolution of a HPGe (high purity germanium) semiconductor detector, they have several advantages: unlike HPGe detectors they operate at room temperature, they are omnidirectional, can be cast or machined to any size or shape, and are cost effective when comparing their stopping power with HPGe or CZT (Cadmium zinc telluride) semiconductors. Of particular interest is the large variety of scintillator materials available, each with unique peak emission wavelength, photon yield, decay time, density, energy resolution, and other properties, it is possible to design a gamma radiation detector fit to nearly any application and deployment. For a fixed- wing UAV mapping nuclear fallout at low altitude this might be a prismatic crystal with a rectangular cross section, whereas for a pipe crawler robot it would be a cylindrical shape. FUTURE ASPIRATIONS // The Bristol University research team and I are collaborating with Hamamatsu, the world's leading SiPM manufacturer, the develop the next iteration of the readout and control electronics based on the 2020 prototype using a SensL/On Semi SiPM. The release of 5th generation 12 bit ADCs by Texas Instruments, with sampling rates up to 10.4 GSa/s designed for 5G applications, are also attractive for modular scintillator based radiation detector designs. Although the FPGA throughput is currently still the bottleneck, RAIN researchers are investigating the opportunities offered by these ADCs. They have the potential to eliminate analog discrimination and pulse shaping circuitry entirely and digitise pulses directly, yielding full gamma spectrometry at unprecedented count rates. 33 REMOTE INSPECTION