Basic performance of unitized Compton scattering type polarimeter

Abstract

A b.st ra c tWe have been developing a Compton scattering type polarimeter which consists of nine unit counters to detect the polarization of hard X-rays from stellar objects such as the Crab Nebula. We constructed one unit counter which consists of one plastic scintillator(7x7x5cm3) and four phoswich scintillators(6.7xl.1x32.2cm3) made of NaI(TI)+CsI(Na). The characteristics of the unit counter were measured in detail to determine the detection efficiency (20.3%) and the modulation factor (27.5%) at 53.4keV. The background spectrum of the unit counter in the laboratory is also measured. Based on the results, the background from the outside of the active collimator is reduced by 50.5% when used with the PSD. On the basis of these results, the performance of the planned polarimeter was estimated by computer simulations. The results showed that the polarimeter can detect the polarization of hard X--rays from the Crab Nebula at a MDP (Minimum Detechble Polarization) of 14.0% with a 3-hour balloon observation.

Digital fast pulse shape and height analysis on cadmium–zinc–telluride arrays for high-flux energy-resolved X-ray imaging

“…Recently, great efforts have been made in the development of imaging arrays, with single-photon counting and energyresolving capabilities, for colour/spectroscopic X-ray imaging (Norlin et al, 2008;Taguchi & Iwanczyk, 2013;Tomita et al, 2004), opening new perspectives for applications within the fields of diagnostic medicine, synchrotron applications, nondestructive testing (NDT) and security screening. Energyresolved photon-counting (ERPC) arrays are typically based on high-Z and wide-band-gap direct-conversion compound semiconductors [gallium arsenide, cadmium telluride, ISSN 1600-5775 # 2018 International Union of Crystallography cadmium-zinc-telluride (CZT)] Barber et al, 2015;Iwanczyk et al, 2009;Szeles et al, 2008;Veale et al, 2014a), able to ensure room-temperature operation and higher detection efficiency than the traditional semiconductor detectors (silicon, germanium) (Del Sordo et al, 2009;Owens & Peacock, 2004;Takahashi & Watanabe, 2001).…”

Status and Future Prospects for γ -ray Polarimetry

“…Unfortunately, instruments that operate in this energy band are usually not constructed using position sensitive low-Z material, but rather they are designed with high-Z materials to maximize photon absorption. Although a few dedicated designs for this regime have been discussed in the literature (e.g., Sakurai et al 1990;Costa et al, 1993;Tomita et al 1996;Cline et al 1997;McConnell et al 2002a;Curado da Silva et al 2003;Larsson & Pearce 2004), none have yet led to an operational instrument.…”