Poissonian-type new radiation imager

A new radiation imager is proposed, which is based on the recent detector technique in high-energy physics experiments; the wavelength shifter coupled to the position-sensitive photomultiplier. The concept model using a CsI(Na) crystal was successfully tested, and a remarkable space resolution, 1.0 mm in FWHM, with detection efficiency of ∼70% has been confirmed for 122 keV gamma rays of 57Co. Improvement in time resolution and possible application of the device to high-flux X-ray imaging are discussed.