Measurement of the Energy Resolution of a X-Y Plastic Scintillating Fiber Stack Detector Coupled to Position Sensitive Photomultiplier Tubes.

The energy resolution is measured for a plastic scintillating fiber detector coupled to position sensitive photomultiplier tubes. A point source (Mn-54) is placed at a distance in front of an x-y plastic scintillating fiber stack which is coupled to two Hamamatsu R2486 position sensitive photomultiplier tubes. At some distance behind this detector another plastic scintillating detector coupled to another position sensitive photomultiplier is placed. Gamma rays interacting in the 1st detector are scattered, and interact with the 2nd detector. By the knowledge of the source location, the Compton interaction location in the 1st detector, and the interaction location of the scattered gamma in detector 2, the scattering angle of the Compton interaction in detector 1 can be determined. From this scattering angle and the known primary gamma energy, the Compton electron energy can be calculated. The energy resolution of the scintillating fiber stack-photomultiplier unit of detector 1 for different Compton electron energies is determined by plotting the experimentally measured electron energies obtained from the light output of the photomultiplier tubes of detector 1.