Real-time transverse-emittance and phase-space monitor

A real-time multislit [1]transverse-emittance monitor has been developed for diagnosing the space-charge-dominated beam in the 10 MeV injection line of the FEL at Thomas Jefferson National Accelerator Facility (formerly CEBAF). It gives emittance, Twiss parameters, and phase-space contours (without any symmetry assumptions) at the update rate of 1 Hz. It reduces measurement noise in real-time, and incorporates a special algorithm for constructing the phase-space matrix, which yields more accurate results by sweeping the beam across the slits. In this paper we will discuss issues relevant to the software design and implementation. Experimental results obtained from a 250 keV photocathode gun will also be presented and compared with other methods and with PARMELA simulations.