Production of 10 MeV /spl gamma/-ray by the backward Compton scattering using an optically-pumped FIR laser at SPring-8

For MeV /spl gamma/-ray production by the backward Compton scattering (BCS), a high power optically-pumped far infrared (FIR) laser has been developed at the synchrotron radiation facility of SPring-8. We obtained about 1.6-W of output power of FIR laser at CH/sub 3/OH 119-/spl mu/m lasing line pumped by 9P(36) branch line of CO/sub 2/ laser. We have constructed a test beamline for a production of 10-MeV /spl gamma/-ray using an accelerator beam diagnosis beamline. FIR laser photons are injected to the beamline against 8-GeV stored electron beam and produced MeV /spl gamma/-rays are extracted to the beamline. We proceed with a /spl gamma/-ray production test at this beamline. It is estimated that the MeV /spl gamma/-rays of 10/sup 3/ photons/sec are obtained with FIR output power of 1.6 W at the test beamline. In future plan, the intensity of /spl gamma/-ray can reach to 10/sup 7/ photons/sec or more by means of installation of an intense MeV /spl gamma/-ray production system by BCS at another new beamline.