Performance testing of an x-ray telescope prototype at Shanghai Synchrotron Radiation Facility

Several imaging x-ray telescope (IXT) prototypes have been fabricated independently by the Institute of Precision Optical Engineering, which employed thermal slumping technology. To verify the performance of the IXT prototypes, a three-layer prototype with a focal length of 2052.5 mm was tested using a narrow beam at the Shanghai Synchrotron Radiation Facility. The performance testing posed a challenge due to the need to suppress the finite source distance effect on the IXT prototype (43-m long source-optic distance). In addition, limited use of motorized stages presents challenges. We present the experimental setups and detailed measurement approaches by utilizing limited measurement devices. The prototype is a segmented telescope comprising six sectors. For the best sector, the measured point spread function (PSF) yields a half power diameter (HPD) of 66″ and agrees well with modeling (62″) and the value measured at PANTER (65″). In addition, the integrated HPD of the whole prototype is 82″ obtained by coadding the PSFs of the six sectors.