Measuring neutron fluences and gamma X-ray fluxes with CCD cameras

The capability to measure bursts of neutron fluences and gamma/X-ray fluxes directly with charge coupled device (CCD) cameras while being able to distinguish between the video signals produced by these two types of radiation, even when they occur simultaneously, has been demonstrated. Volume and area measurements of transient radiation-induced pixel charge in English electric valve frame transfer charge coupled devices from irradiation with pulsed neutron sources (14 MeV) and bremsstrahlung photons (16-MeV endpoint) are utilized to calibrate the devices as radiometric imaging sensors capable of distinguishing between the two types of ionizing radiation. Measurements indicate approximately 0.5 V/rad responsivity with >or=1 rad required for saturation from photon irradiation. Neutron-generated localized charge centers or peaks binned by area and amplitude as functions of fluence in the 10/sup 5/ to 10/sup 7/ n/cm/sup 2/ range indicate smearing over approximately 1 to 10% of the CCD array with charge per pixel ranging between noise and saturation levels.<
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