Time-resolved position measurements of an intense relativistic electron beam propagating through gas using fast framing camera

Abstract

Summary form only given. A fast framing camera (gated optical imager) is being used to measure the transverse offset of an electron beam during propagation through gas. The 5-MeV, 20-kA, 40-ns beam from SuperIBEX is injected into an IFR (ion-focused regime) cell to tailor the beam radius. Then the beam is passed through a B/sub /spl theta-cell, which is a drift tube with a current-carrying wire on axis, for centering. After this, the beam is injected into an air chamber in which the pressure is set to 760, 600, or 400 torr. In this chamber a thin sheet of quartz is placed in the beam path. The resulting Cherenkov radiation is viewed by the gated optical imager (GOI). The GOI provides three images of the beam profile during the beam pulse using a 2-ns shutter speed. The images are stored on a computer a provide a full two-dimensional image representing the beam current density cross-section.