Characterization of a windowless Si(Li) detector in the photon energy range 0.1-5 keV

Abstract Synchrotron radiation from the electron storage ring BESSY has been used to determine the absolute detection efficiency (DE) and the response function of a windowless Si(Li) detector in the 0.1–5 keV photon energy range. The determination of the DE above 0.4 keV was based on an energy dispersive measurement of the undispersed calculable radiation emitted from the storage ring, which is a primary radiation standard. A new method based on the measurement of the detector photocurrent for a known monochromatic spectral photon flux was used to measure the DE down to 60 eV. We have introduced a model for the absolute DE including all parts of the response function of a Si(Li) detector which expresses the DE only as an absorption effect in the gold contact and contamination layers. The agreement between the measured efficiency and the model calculation is better than 2%. A model that allows lineshapes from 0.1 keV upwards to be simulated and which agrees well with our measurements in the range up to 5 keV is presented.

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