Proof of Principle Experiments for Compton Scattering of a Stored Photon in a Supercavity.

We observed that Compton-scattered photons are enhanced in a supercavity. We can increase the laser beam intensity in such a cavity and obtain a reasonable number of scattered photons. In our experiments, an e-beam of ~82 keV and a 1 µ m wavelength laser beam were used in the supercavity. The storage rate of the supercavity was ~4000 times. The wavelength of the scattered photons was calculated to be 364 nm and the flux to be approximately 400 [photons/s]. The experimental results agree well with the theoretical prediction.