A high pressure xenon self-triggered scintillation drift chamber with 3D sensitivity in the range of 20–140 keV deposited energy

A high pressure gas self-triggered scintillation drift chamber has been built with a working volume of 30 cm diameter and 4 cm depth, viewed through glass windows by an array of 19 PMTs. The detector tested at 9 bar xenon filling showed 2.7% FWHM energy resolution at 122 keV over a 22 cm field of view and three-dimensional sensitivity with X,Y resolution of 3.7 mm FWHM and Z resolution of 0.6 mm FWHM for 60 keV photoabsorbed γ-rays. The readout system of the detector is able to select multi-vertex events occurring in the sensitive volume due to γ-ray absorption and discriminate fluorescent photons, Compton scattering and photoabsorption vertices. The energy resolution in “fluorescent photon gated mode” has been measured as 2.2% FWHM at 122 keV γ-ray. Some possible applications of the detector are discussed.