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The Tandem Etalon Magnetograph (TEM) is one of the instruments of the SolarMagnetic Activity Research Telescope of Hida Observatory. The TEM is a partialdisk (320" x240") filter magnetograph which scans the wavelength around a Fe Iline at 6303 angstrom and achieves polarimetric sensitivity of < 5x10^-4 foreach wavelength. To obtain the polarimeter response matrix of the instrument,we have carried out end-to-end polarization calibrations of the instrument. Wehave also measured the polarization characteristics of the polarization beamsplitter (PBS), which is a crucial component of the instrument. As a result ofend-to-end calibration, we found significant spatial variation in the responsematrix across the field of view. From a laboratory test, we found that 1% ofthe magnitude of a circular diattenuation of the PBS was due to the retardationcaused by the stress in the cube and the linear diattenuation of the film.Although the spatial variation across the field of view is more than ten timeslarger, to achieve the polarimetric sensitivity of < 5x10^-4, this can be wellexplained by the polarization characteristic of the PBS and corrected by usingthe response matrix obtained in the end-to-end calibration. In addition, wealso obtained the daily variation of the polarization property of the TEM. Wefound that the crosstalk from Stokes Q to V changes an amount comparable to thetolerance through a day. In the present configuration, we require apixel-by-pixel calibration every 100 minutes to meet the accuracy requirement.

Polarization calibration of the Tandem Etalon Magnetograph of the Solar Magnetic Activity Research Telescope at Hida Observatory