S. E. Korbly

Design and emission uniformity studies of a 1.5-MW gyrotron electron gun

We present the design and initial operation of a 96-kV 40-A magnetron injection gun for a 1.5-MW 110-GHz gyrotron. A critical parameter for the successful application of this electron gun is the uniformity of electron emission. The current-voltage curve of emission, at a series of temperatures, is measured. Analysis indicates that the work function of the emitter is 1.6 eV with a (total) spread of 0.07 /spl plusmn/ 0.01 eV. Measurement of the azimuthal emission uniformity with a rotating probe indicates that the work function variation around the azimuth, the global spread, is 0.04 /spl plusmn/ 0.02 eV. The spread due to local (microscopic scale) work function variations is then calculated to be 0.06 /spl plusmn/ 0.02 eV. Temperature variation can be ruled out as the cause of the observed emission nonuniformity.

Design of a Smith-Purcell radiation bunch length diagnostic

We present the design of a Smith-Purcell radiation diagnostic to measure the micro bunch length of a 20MeV, 17 GHz electron bunch train. The bunch length can be determined by measuring the frequency and angular distribution of the emitted radiation as proposed by Nguyen[1]. The beam is produced by a 17 GHz, 50 MeV/m traveling wave (TW) accelerator built by Haimson Research Corporation (HRC). The high operating frequency of this accelerator allows for the production of ultra-short bunches of about 180 femtoseconds. We will present detailed calculations of the optimization of the experimental system and of the expected bunch length resolution.

Frequency-locked terahertz Smith-Purcell radiation

We present experimental measurements of coherent frequency-locked Terahertz Smith-Purcell radiation generation by a train of 15 MeV, femtosecond-scale electron bunches passing over a metal grating. This scheme leads to an increase in intensity by the number of grating periods, the number of electron bunches and the number of electrons in each bunch. This powerful SPR THz radiation can be detected with a high signal to noise ratio by a heterodyne receiver.

Progress on a Smith-Purcell radiation bunch length

A Smith-Purcell radiation diagnostic to measure the microbunch length of a 20 MeV, 17 GHz electron bunch train is being implemented at MIT. The bunch length can be determined by measuring the frequency and angular distribution of the emitted radiation. The beam is produced by a 17 GHz, 50 MeV/m traveling wave accelerator built by Haimson Research Corporation (HRC). The high operating frequency of this accelerator allows for the production of ultrashort bunches of about 180 femtoseconds. At this time we are assembling the experiment and we will present an update on the progress.

A Smith-Purcell radiation bunch length diagnostic

We present the design of a Smith-Purcell radiation diagnostic to measure the micro bunch length of a 20MeV, 17 GHz electron bunch train. The bunch length can be determined by measuring the frequency and angular distribution of the emitted radiation as proposed by Nguyen (1997) and demonstrated by Doucas et al. (2002). The beam is produced by a 17 GHz, 50 MeV/m traveling wave (TW) accelerator built by Haimson Research Corporation (HRC). The high operating frequency of this accelerator allows for the production of ultrashort bunches of about 180 femtoseconds. We present detailed calculations of the optimization of the experimental system and of the expected bunch length resolution.