Single-shot measurement of transverse second moments using the projection method

Abstract

We introduce a diagnostic for measuring the transverse phase space (TPS) and transverse second moments of a particle beam in a single shot. The diagnostic consists of a slit followed by a simple projection beam line to project the TPS onto an imaging screen. The beam line is composed of a skew quadrupole magnet followed by a normal quadrupole magnet with an imaging screen at the end. The skew quadrupole generates a coupling between the initial x and the final y, while the normal quadrupole removes the correlation between the initial x and the initial x′. Thus, the initial (x,x′) is mapped onto the final (x,y). The slit is needed before the projection beam line to remove the initial (y,y′) contribution from the final (x,y) image on the screen. We present simulation studies and a demonstration of the diagnostic with an experiment performed at Argonne Wakefield Accelerator facility. We also discuss the method's limitations.