Compact Compton polarimeter utilizing silicon drift detectors

A compact 90 degree-Compton scatter polarimeter has been developed to be used for energy resolved linear polarization analysis of Parametric X-radiation (PXR) in the energy range below 10 keV. The polarimeter employs 4 thermoelectrically cooled silicon drift detectors of excellent noise performance directed at a conical beryllium scatterer under azimuths spaced by 45 degrees to measure the azimuthal modulation of Compton scatter yields. One further drift detector is used to align the narrow PXR radiation cone with respect to the polarimeter axis. The polarization sensitivity and instrumental asymmetries of the polarimeter have been studied with monochromatized synchrotron radiation at energies from 6 to 11 keV. The analyzing power is close to unity in agreement with expectations and Monte Carlo simulation results. Instrumental asymmetries of a few percent have been measured and corrected for with residual statistical uncertainties of (Omicron) (10 -3 ). The orientation of the polarization plane is determined to within less than 4 milliradians.