A method for measuring dark current electron beams in an RF linac

摘要

X-ray fluorescence from thin foilsinserted into the Naval Postgraduate School linachas been used to measure the integrated electronbeam intensity when the accelerator is operatingwith dark current. The measured x-ray flux, theknown inner shell ionization cross sections andradiative transition probabilities are used toobtain measurements of dark currents of the orderof 10-14 Amperes. The same arrangement allowscontinuous, in-situ energy calibration of our SiLidetector in the electromagnetic noise environmentof the linac. This technique was originallydeveloped to perform absolute productionefficiency measurements of parametric x-raygeneration in the 5 - 50 keV range.