Development of an EUV polarimeter with a transmission multilayer

We developed an EUV polarimeter consisting of a transmission multilayer and a back-illumination CCD. The transmission of the multilayer at an incident angle of45-deg depends on the polarization angle. We developed a polarimeter by using the transmission. Advantages of usage a transmission multilayer are as follows. 1) The mechanics is simple, because we do not need to move the detectors. 2) High energy photons, where the multilayer is transparent, can be measured as a normal observation, if we use a CCD as a photon counting. 3) By removing the multilayer from the optical axis, normal observation with a CCD can be performed. A stand alone multilayer of Mo/Si was fabricated, which consists of seven layer-pairs with a thickness of 20 nm. We evaluated the performance of the polarimeter using a synchrotron beam line. We confirmed a modulation factor of 47% around 95 eV.