Evaluation of the degree of linear polarization at 0.88 keV by use of mica crystal polarizer

Imazono, Takashi; Hirono, Toko*; Kimura, Hiroaki*; Saito, Yuji  ; Muramatsu, Yasuji*; Sano, Kazuo*; Ishino, Masahiko; Koike, Masato

We have developed crystal-type polarizing elements to evaluate the state of polarization of soft X-ray in the 1-keV region. In our previous study, we have found out that natural muscovite mica is a promising candidate for a reflection-type polarizer at 0.88 keV. The polarization performances of muscovite and fluorophlogopite micas were evaluated by the rotating-analyzer method at the BL23SU beamline, which tuned to the horizontal linear polarization mode, of SPring-8. As the result, fluorophlogopite mica was found to be high efficient reflection-type polarizer having the polarizance of 0.998. Also, using it, the degree of linear polarization of the incident light was determined to be 0.993 at 0.88 keV.