A beam-profile monitor for the BNL Accelerator Test Facility (ATF)

A beam-profile monitor has been designed to diagnose the 5 MeV, high-brightness electron beam from the RF gun of the BNL (Brookhaven National Laboratory) Accelerator Test Facility (ATF). The monitor consists of a phosphor screen viewed by a CCD (charge coupled device) camera. The video images are digitized and stored by a frame grabber, and analyzed on an IBM PC-AT to extract the emittance. Details of the hardware configuration are presented, along with the spatial resolution of the system measured as a function of phosphor-screen thickness. The strategies which will be used to measure the transverse and longitudinal emittances are briefly mentioned. The system should be capable of measuring a transverse geometric emittance of around 1 mm-mrad, as will be typical of the ATF beam.<>