Detection of low-energy X-rays using self-scanning photodiode arrays

An experimental investigation into the applicability of self-scanning photodiode arrays to the detection of low energy x-rays has been performed. The photodiode array used in this experiment is a 1024 pixel linear array coupled to a fiber optic faceplate which is coated with a phosphor screen for enhanced x-ray sensitivity. This device was exposed to low energy x-rays emitted from plasmas produced at the LPARL pulsed laser facility. Absolute calibration of the photodiode array response was achieved by comparison of array output signals with those from calorimeters and x-ray detectors of known sensitivity. Radiation emitted from the laser-induced plasma was filtered by beryllium foils to protect the array from light and particles from the plasma. An initial spectral calibration of the array was obtained by using several laser target materials. The spectral content of the filtered radiation from the various laser-induced plasmas is 700 to 1800 eV. The spatial resolution of the array was checked by interposing slits and masks between the plasma and the array. Results show that the photodiode array has a sensitivity similar to that of Kodak 101 x-ray film, while the dynamic range of the array is much larger than Kodak 101 film