DEVELOPMENT OF AN ORTHOGONAL-STRIPE CDZNTE GAMMA-RADIATION IMAGING SPECTROMETER

We report, performance measurements of a sub-millimeter resolution CdZ nTe strip detector developed as a prototype for astronomical instrumen ts operating with good efficiency in the 30-300 keV photon energy rang e. The prototype is a 1.4 mm thick, 64 x 64 contact stripe CdZnTe arra y of 0.375 mm pitch in both dimensions. Pulse height spectra were reco rded in orthogonal-stripe coincidence mode which demonstrate room-temp erature energy resolution < 10 keV (FWHM) for 122 keV photons with a p eak-to-valley ratio > 5:1. Good response is also demonstrated at highe r energies using a coplanar grid readout configuration. Spatial resolu tion capabilities finer than the stripe pitch are demonstrated. We pre sent the image of a Ba-133 source viewed through a collimator slit pro duced by a 4 x 4 stripe detector segment. Charge signals from electron and hole collecting contacts are also discussed.