SGEMP Simulation Experiments with Electron Beams

An alternative to utilizing laboratory photon sources, which have limited capabilities for the investigation of space-charge-limited SGEMP response, is to use large-area electron beams , which are readily available. If the experiment is analyzed by the same methods used for the analysis of a photon exposure, a validation of a major portion of the SGEMP analysis procedure is possible. An experiment is reported in which a 30-cm diameter electron pulse from one of the Simulation Physics, Inc., generators was emitted from the center of a 60-cm diameter, 2-meter long cylinder located on the axis of a 3-meter diameter, 4-meter long vacuum tank. Magnetic field measurements were made at nine locations on the cylinder, and at the outer tank wall. The characteristics of the electron beam (peak current ~3.5 kA, mean energy ~12 keV, FWHM ~2.5 nsec) were measured with the same diode setting and beam profile. Electron spectra were obtained with the SPI magnetic spectrometer at three radii. Computer calculations with the ABORC code, using the measured time-dependent electron spectrum, gave excellent agreement with the magnetic fields measured at various locations on the cylinder.