Non-planar four-mirror optical cavity for high intensity gamma ray flux   production by pulsed laser beam Compton scattering off GeV-electrons
  As part of the R&D toward the production of high flux of polarised Gamma-rays we have designed and built a non-planar four-mirror optical cavity with a high finesse and operated it at a particle accelerator. We report on the main challenges of such cavity, such as the design of a suitable laser based on fiber technology, the mechanical difficulties of having a high tunability and a high mechanical stability in an accelerator environment and the active stabilization of such cavity by implementing a double feedback loop in a FPGA. 
J. Bonis, R. Chiche, R. Cizeron, M. Cohen, E. Cormier, P. Cornebise,   N. Delerue, R. Flaminio, D. Jehanno, F. Labaye, M. La...
physics.acc-ph physics.ins-det