There is much interest in developing new scintillator detectors for radiation detection and radiographic imaging
applications. The knowledge of the electron mobility (μ) is important in the basic understanding of charge transport and
in the selection and optimization of many inorganic scintillator materials such as thallium-doped cesium iodide, CsI(Tl).
Performance measures are used to model various scintillator responses in an effort to predict the effect of doping
concentrations. Performance models will help in the new scintillator design process. Initial tests are done with cadmium
zinc telluride detectors to establish measurement techniques and baselines.
Silicon-based photodetectors offer several benefits relative to photomultiplier tube-based scintillator systems. Solid-state
photomultipliers (SSPM) can realize the gain of a photomultiplier tube (PMT) with the quantum efficiency of silicon.
The advantages of the solid-state approach must be balanced with adverse trade-offs, for example from increased dark
current, to optimize radiation detection sensitivity. We are designing a custom SSPM that will be optimized for green
emission of thallium-doped cesium iodide (CsI(Tl)). A typical field gamma radiation detector incorporates thallium
doped sodium iodide (NaI(Tl)) and a radiation converter with a PMT. A PMT's sensitivity peaks in the blue wavelengths
and is well matched to NaI(Tl). This paper presents results of photomultiplier sensitivity relative to conventional SSPMs
and discusses model design improvements. Prototype fabrications are in progress.
At Los Alamos National Laboratory (LANL), a high-speed, four-wavelength, infrared (IR) pyrometer has been used for surface temperature measurements in shock-physics experiments for several years. The pyrometer uses solid-state detectors and a single fiber-optic cable for transmission of light from the target surface to the detectors. This instrument has recently been redesigned for an upcoming experiment at the Nevada Test Site (NTS). Three different IR detectors (two HgCdTe variants as well as the existing InSb chip) were compared for sensitivity, signal-to-noise ratio, and bandwidth. Of major concern was detector amplifier recovery time from overload saturation. In shock-physics experiments, a short but very bright precursor frequently accompanies shock breakout (often from trapped air). This precursor can saturate the amplifier and may "swamp-out" the signal of interest before the amplifier recovers. With this in mind, we evaluated two new amplifier designs by the Perry Amplifier Company for linearity, signal-to-noise characteristics, gain, and saturation recovery time. This paper describes experimental setup for detector comparison and results obtained. Furthermore, we discuss new amplifier design and suitability for high-speed infrared pyrometry in shock physics experiments.