SILICON DRIFT DETECTORS FOR HIGH-RESOLUTION ROOM-TEMPERATURE X-RAY SPECTROSCOPY

New cylindrical silicon drift detectors have been designed, fabricated and tested. They comprise an integrated on-chip amplifier system with continuous reset, on-chip voltage divider, electron accumulation laye r stabilizer, large area, homogeneous radiation entrance window and a drain for surface generated leakage current. The test of the 3.5 mm(2) large individual devices, which have also been grouped together to fo rm a sensitive area up to 21 mm(2) have shown the following spectrosco pic results: at room temperature (300 K) the devices have shown a full width at half maximum at the Mn-K alpha line of a radioactive Fe-55 s ource of 225 eV with shaping times of 250 to 500 ns. At -20 degrees C the resolution improves to 152 eV at 2 mu s Gaussian shaping. At tempe ratures below 200 K the energy resolution is below 140 eV. With the im plementation of a digital filtering system the resolution approaches 1 30 eV. The system was operated with count rates up to 800 000 counts p er second and per readout node, still conserving the spectroscopic qua lities of the detector system.