Thin scintillators and position sensitive photomultiplier tubes for hard X-ray imaging in space

Monolithic and segmented CsI(Tl) scintillators coupled to a position sensitive photomultiplier tube (PSPMT) have been tested for imaging and environmental performance necessary for hard X-ray astrophysics missions. Using a crossed-wire PSPMT and individual anode-wire readout, spatial resolution of 1-2 mm rms at 60 keV over the entire photo-cathode imaging surface is obtained out to near the edges of the scintillator. A PSPMT mapping correction was used to obtain energy resolution close to what is expected from CsI(Tl) scintillators.