High sensitivity image intensifier tube device for hard-x-ray detection

We present an x-ray detector with a high sensitivity in the 1-20 MeV x-ray range. This device consists of a scintillator coupled with a microchannel plate image intensifier tube working in the visible range. The performance of the hard-x-ray detector is described. The modulation transfer function, the characteristic curve, and the detection threshold were measured. Using an x-ray flash generator in the 4 MeV x-ray range, we have been able to record images of dense spheres for dose levels as low as 1.5 mu Gray. Similar experiments have been realized with a linear accelerator for different x-ray spectra (10 and 20 MeV). Our results demonstrate that this device works in a range where the most sensitive intensifying screens and films, usually used on flash radiography, are inoperative. (C) 1996 American Institute of Physics.