Description
$\rm{}^{82}Se$ is an interesting candidate for a $0\nu\beta\beta$ search due to its high $Q_{\beta\beta}$ (2998 keV) value, which is above many natural radioactive backgrounds, and relatively long $T^{2\nu}_{0.5}$ ($10^{20}$ yrs). We have proposed a tower of low noise pixelated CMOS detectors with a $200 \, \rm \mu m$ layer of amorphous selenium (a-Se) as a $0\nu\beta\beta$ experiment. The high spatial resolution of a pixelated detector improves background rejection from Compton scattering and single $\beta$ decays and highlights the desired topology of two $\beta$s from a single vertex. We will present results on our initial investigation into the resolution of a-Se using a single pixel detector with $\sim100$ keV $\gamma$-rays and the impact of this study on the energy resolution in the $Q_{\beta\beta}$ range of selenium. Additionally, we will discuss our work on depositing a-Se on the existing TopMetal-II${}^-$ chip (72x72 pixels) and moving towards a full pixelated CMOS detector.
