Title :
An emittance measurement system for a wide range of bunch charges
Author :
Dunham, B. ; Engwall, D. ; Hofler, A. ; Keesee, M. ; Legg, R.
Author_Institution :
Thomas Jefferson Nat. Accel. Facility, Newport News, VA, USA
Abstract :
As a part of the emittance measurements planned for the FEL injector at the Thomas Jefferson National Accelerator Facility (Jefferson Lab.), we have developed an emittance measurement system that covers the wide dynamic range of bunch charges necessary to fully characterize the high-DC-voltage photocathode gun. The measurements are carried out with a variant of the classical two-slit method using a slit to sample the beam in conjunction with a wire scanner to measure the transmitted beam profile. The use of commercial, ultralow noise picoammeters makes it possible to cover the wide range of desired bunch charges, with the actual measurements made over the range of 0.25 pC to 125 pC. The entire system, including its integration into the EPICS control system, is discussed
Keywords :
accelerator control systems; electron accelerators; electron guns; free electron lasers; linear accelerators; particle beam bunching; particle beam diagnostics; particle beam injection; photocathodes; EPICS control system; FEL injector; Thomas Jefferson National Accelerator Facility; bunch charges; emittance measurement system; high-DC-voltage photocathode gun; transmitted beam profile; ultralow noise picoammeters; wire scanner; Cathodes; Control systems; Current measurement; Data acquisition; Dynamic range; Micromotors; Noise figure; Particle measurements; Pulse measurements; Wire;
Conference_Titel :
Particle Accelerator Conference, 1997. Proceedings of the 1997
Conference_Location :
Vancouver, BC
Print_ISBN :
0-7803-4376-X
DOI :
10.1109/PAC.1997.751155
