Accession Number : ADA338496

Title :   MIT Microwiggler for Free Electron Laser Application. Non-perturbative Electron Beam Characterization with a Microwiggler

Descriptive Note : Final technical rept. 30 Sep 90-25 Feb 98

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS

Personal Author(s) : Haus, Hermann A.

PDF Url : ADA338496

Report Date : 25 FEB 1998

Pagination or Media Count : 145

Abstract : The potential of undulators to provide beam diagnostic information has been cited in the literature for many years. We demonstrate that while important parameters describing the beam - the energy, energy spread, divergence, spot size, matching and bunchlength - are convolved together in the synchrotron emission, a careful experimental setup can extract divergence, energy spread and bunchlength from this convolution. The MIT microwiggler is uniquely suited for the development and testing of electron beam diagnostic techniques. A pulsed electromagnet with long length and extensive tunability, it provides flexibility and high quality at a period short enough to produce visible radiation at moderate beam energies (40-55 MeV). We have achieved a field uniformity of 0.08% in rms peak amplitudes and have performed measurements to test this claim against a comprehensive set of criteria, thus marking the first time this figure of merit has been reduced below 0.1% in any sub-cm period wiggler. Studies with electron beam were performed at the Accelerator Test Facility at BNL. The long term statistics collected of the wiggler performance under full operation will be documented. The production of visible radiation, where numerous diagnostics are readily available, makes single shot techniques a special strength of the microwiggler. We have developed a family of beam diagnostic techniques with the wiggler, making use of the spectrum, spatial profile, and fluctuational characteristics of its emissions. Cone measurements are used to characterize divergence and energy spread. The systematic diagnosis and understanding of the spontaneous emission characteristics is important in determining when Self Amplified Spontaneous Emission begins. This is discussed in the context of measurements of SASE at 1.064 microns.

Descriptors :   *ELECTRON BEAMS, *FREE ELECTRON LASERS, *WIGGLER MAGNETS, MAGNETIC FIELDS, ELECTRON ENERGY, LASER APPLICATIONS, ELECTRON EMISSION, VISIBLE SPECTRA, ELECTRON FLUX, SYNCHROTRONS.

Subject Categories : Electricity and Magnetism
      Particle Accelerators
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE