19-ELEMENT HIGH-PURITY GE SOLID-STATE DETECTOR ARRAY FOR FLUORESCENCEX-RAY-ABSORPTION FINE-STRUCTURE STUDIES

We describe a 19-element high-purity Ge solid-state detector array dev eloped for high-throughput fluorescence X-ray absorption fine structur e (XAFS) experiments in ultra-high vacuum (UHV). The packing ratio is 57%, a significant improvement over that of standard 13-element arrays (37%). The average energy resolution in the 19 channels is similar to 170 eV at 5.9 keV with an amplifier shaping time of 6 mu s. The detec tor array can be used up to a count rate of 200 kcps per channel using a shaping time of 0.5 mu s and a dead-time correction. A total count rate of 3.8 x 10(6) cps is obtained with an energy resolution of 240 e V. Capability of the new detector for fluorescence-detected XAFS appli cations is demonstrated for 1000 Angstrom thick YBa2Cu3O7 on SrTiO3 su bstrate and similar to 0.1 monolayer of As atoms on an InP(001). (C) 1 998 Elsevier Science B.V. All rights reserved.