A study on angular resolution and energy resolution of imaging plate for heavy particles

We have been investigating basic characteristics of an Imaging Plate to apply it for dE/dx detector of ultraheavy cosmic rays. To determine the kind of nuclide in accuracy, excellent angular resolution and excellent energy resolution are required. So we have measured them utilizing heavy ion accelerator. As the results, we recognized that the angular resolution can be less than 0.4 degree setting two Imaging Plates distant more than I cm. On the other hand, the energy resolution is at most 30 % at present and the energy resolution does not depend on the deposited energy. It indicates that the photon statistics is not dominant for the energy resolution but that the other unknown factor is dominant. From beam experiments, we recognized that the energy resolution is not affected by neither fading effect nor background accumulation.