Measurements of E1 and M1 multipolarity of Cr-52 using nuclear resonance fluorescence

Shizuma, Toshiyuki; Hayakawa, Takehito; Minato, Futoshi   ; Daito, Izuru*; Negm, H.*; Ogaki, Hideaki*; Miyamoto, Shuji*

Mono-energetic and linearly polarized (LCS) -rays can be generated by Compton scattering of laser light with high energy electrons. In nuclear resonance fluorescence (NRF), spins of the excited states and their transition probabilities can be extracted in a model independent way. In addition, by using high polarization of LCS -rays, it is possible to precisely determine multipolarity (E1 or M1) of the NRF -rays, i.e., parities of the excited states. We have performed NRF measurements at the NewSUBARU electron ring facility of University of Hyogo. LCS -rays with maximum energies of 8.2, 8.8, 9.4, 10, 11, and 12 MeV were used to irradiate a natural Cr target. From results of the measurements we have determined the parities of the excited states below the neutron separation energy of about 12 MeV. In this paper, we will report the results of the measurements and the comparison of the dipole strength distribution with the RPA calculation.