Center for Medical and Materials Research with Free-Electron Laser.
Final rept. 15 Sep 91-31 Dec 94.
VANDERBILT UNIV NASHVILLE TN
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During the period of this contract the Vanderbilt FEL emerged as a reliable source of radiation for applications research. From April 1992 to June 1993 the FEL had its first golden era, providing 2200 hours for applications research. The advances achieved with this beam time are summarized by the users in following sections of this report. In June 1993 the FEL began a planned shutdown to begin implementation of the Compton X-ray and other upgrades. This shutdown period extended longer than planned due to an unfortunate series of component failures. We now have a substantially more aggressive approach to insure reliable operation for example, maintaining spare parts and more rapidly responding to component failures. Consequently, we have provided 281 hours from 16 May 1994 to the end of 1994 and 443 hours of beam time from 11 January 1995 through 8 March 1995. We believe the 1995 operation signifies the beginning of our second golden era at the Vanderbilt FEL Center. We have recently extended the operating day from 7 a.m. to midnight, 4-12 to 5 days per week, reflecting that we have indeed achieved routine operation. In addition to providing more beam time, we have also steadily improved beam performance over the period of this contract. The dielectric-mirror optical cavity design has proven successful with operation from 2.0 to 9.5 microns. The intensity of the delivered beam is much higher at the focus due to improved optical quality, but it should be noted that the total output power about 120 mJmacropulse remains somewhat less than that provided by the previous cavity design 200 mjmacropulse. Currently we are investigating possible causes, in particular an instability in the turn-on of the electron beam.
- Medicine and Medical Research
- Lasers and Masers