A SILICON COMPOSITE THERMAL AND IONIZATION X-RAY-DETECTOR

We have made a combination calorimetric and ionization X-ray detector by attaching a silicon p-i-n diode to a monolithic silicon microcalori meter. Applying a bias to the diode enhanced the thermal signal, and w ith a reverse bias of 25 V we achieved a detection threshold of 8 eV, based upon energy scaling of the standard deviation of the baseline no ise. We were able to measure a charge signal in the absence of applied bias on the diode, demonstrating that the junction potential is suffi cient to drift the ionized charges to the contacts. A fraction of the electron-hole pairs created became trapped, manifested by excess broad ening in the measured thermal signal and by using the variation of the thermal signal magnitude with reverse bias to fit for the fraction of charge that is trapped. The ability to collect charge without an appl ied bias is necessary to produce high resolution combination thermal a nd ionization detectors.