Determination of Sensitivity and saturation limit of phosphor imaging plates for photon energies up to 1.25MeV

Sensitivity calibration of imaging plates (IP) is important for quantitative measurements of intensity data obtained in various X-ray and gamma radiography experiments. To test the sensitivity of the IP (BAS2025) with the scanner (BAS5000) for higher photon energies, we have performed gamma exposure experimentsusing radionuclide (Co-57, Ba-133, Cs-137, Na-22 and Co-60). This provides useful information in assessing the intensities and dose received on IP in radiography especially with flash X-rays in the range 250keV to 1MeV.The IP was exposed for prolonged time to determine the saturation dose limit. The PSL intensity increases linearly up to 8x10 3 with dose received. With further increase in dose the intensity goes nonlinear till it gets saturated at ~9070 PSL. The observed photon sensitivity was measured as 1.383 x10 -4 PSL/photon for 114 keV, 1.101 x 10 -3 for 266 keV, 1.316 x 10 -3 for 662 keV, 4.111 x 10 -5 for 784 keV and 6.449 x 10 -5 for 1250 keV.Both the sensitivity and the saturation dose are dependent on the photon energy.The calibration data of the SR2025 IP is used in assessing the dose in flash radiography experiments.