An ISPA-camera for gamma rays in nuclear medicine

With the recently developed ISPA (Imaging Silicon Pixel Array)-tube we achieved high position-sensitive detection efficiency of 57Co-122 keV photons, via a matrix of YAlO3-crystals (YAP), 5 mm long, 0.6 x 0.6 mm2 cross-section. The ISPA-tube is only 4 cm long with 3.5 cm diameter and consists of a photocathode viewed at 3 cm distance by a silicon pixel chip, directly detecting the photoelectrons. The chip-anode consists of 1024 rectangular pixels with 75 μm x 500 μm edges. Each pixel is bump-bonded to its individual front-end electronics which provides read-out times between 6 and 12 μs. Apart from its already demonstrated application in HEP for particle tracking with scintillating fibres, the ISPA-tube provides also an excellent tool in medicine, biology and chemistry. (orig.)