CERN Accelerating science

Article
Title	Recent Results from the IR Upgrade FEL at Jefferson Lab
Author(s)	Benson, S V ; Beard, K ; Behre, C P ; Biallas, G H ; Boyce, J ; Douglas, D ; Dylla, H F D ; Evans, R ; Grippo, A G ; Gubeli, J G ; Hardy, D ; Hernandez-Garcia, C ; Jordan, K ; Merminga, L ; Neil, G ; Preble, J P ; Shinn, M D ; Siggins, T ; Walker, R L ; Williams, G P ; Zhang, S
Affiliation	(Jefferson Lab, Newport News, Virginia JAEA/FEL, Ibaraki-ken)
Publication	2005
In:	27th International Conference on Free Electron Lasers, Palo Alto, CA, USA, 21 - 26 Aug 2005, pp.e-proc. MOOB004
Subject category	Accelerators and Storage Rings
Abstract	After demonstrating 10 kW operation with 1 second pulses, the Jefferson Lab program switched to demonstrating high power operation at short wavelengths using a new 8 cm period wiggler and a THz suppression chicane. We report here on the lasing results to date using this new configuration. We have demonstrated a large reduction in THz heating on the mirrors. We have also eliminated heating in the mirror steering assemblies, making operation at high power much more stable. Finally, we have greatly reduced astigmatism in the optical cavity, allowing operation with a very short Rayleigh range. The laser has been tuned from 0.9 to 3.1 microns using the new wiggler. User experiments commenced in April of 2005 with the FEL Upgrade operating over the 1-3 micron range. We are in the process of installing a 5.5 cm permanent magnet wiggler that will give us even larger tuning range and higher power.