Dosimetry for Thin Biological Samples Irradiated by Nanosecond Electron Pulses of High Intensity

Abstract

Pulsed electron sources such as 600 kV field emission generators can deliver doses in excess of 106 rads in single pulses having duration times of a few nanoseconds. When these sources are used to irradiate thin layers of cells the measurement of absorbed dose is complicated by the associated high dose rates, the relatively low electron energy, and the thickness of the sample which may be only a few microns. In this laboratory the problem of measuring absorbed dose has been investigated by the use of thin discs of Pilot-B, a commercially available fast response plastic scintillator. The measurement of light pulses from the scintillator was accomplished with a nanosecond pulse integrator constructed at our laboratory. The determination of the dose absorbed by a cell layer made use of an extrapolation technique in which varying thicknesses of a scintillator disc were placed at the irradiation position in the same geometry as the cellular layer. A thin foil absorbed dose calorimeter was constructed to provid...