Position Sensitive Photomultiplier Tubes for Scintillation Imaging

The Position Sensitive Photomultiplier Tube (PMT) was developed mainly for scintillation imaging in the field of high energy physics and medical applications. This PMT consists of a proximity-type photocathode and 11 staged mesh dynodes. For performing two-dimensional detection, two sets of wire anodes arranged in perpendicular with each other performs a read-out of the secondary electrons emitted from the last dynode. The intrinsic spatial spread of 4.3 mm FWHM and resolution of 0.3 mm FWHM were obtained for 4000 photons/pulse with LED by centroid calculation. Also, this PMT features an amplification gain of 10/sup 6/ and a quantum efficiency of 20% allowing for low energy radiation measurements and providing an energy resolution that is nearly the same as that of the conventional PMT. Finally, the authors show the reconstruction of two dimensional/scintillation image with 3'' diameter NaI(T1) crystal.