POLARIZED GAMMA-RAYS WITH LASER-COMPTON BACKSCATTERING

Completely polarized gamma-rays can be generated by Compton backscatte ring of laser light. The energy of the polarized gamma-rays ranges fro m 1 to 10 MeV by using a Nd:YAG laser and the storage ring TERAS at El ectrotechnical Laboratory. The energy spread of the gamma-rays varies from 1 to 4% according to its energy. The gamma-ray yield is measured to be 47.2 photons mA(-1) W-1 s(-1). By using these polarized gamma-ra ys elastically scattered photons have been measured. The parity of the J = 1 level in Pb-208 (E(X) = 5.514 MeV) was clearly determined to be negative and the parity of the J = 1 level in B-11 (E(X) = 4.4451 MeV ), on even-odd nucleus, was also measured to be negative. Further deve lopment in the SR-FEL will allow us to use similar to 10(7) gamma-rays .