The high spectral resolution detection of hard X-rays (E > 20 keV) is a challenging and nearly unexplored area in Space Astrophysics.
Traditionally used CdTe/CdZnTe semiconductor based hard x-ray detectors present moderate spectral resolution (several hundred eV @ 60 keV), while a resolution of few tens of eV could open new frontiers in the study of nuclear processes and high temperature plasma dynamics in energetic processes such as the coalescence of compact objects or energetic flares in the Sun or active stars. This can be achieved by using properly designed cryogenic microcalorimeters. Presently, such devices are currently investigated for the detection of soft X-rays from astrophysical sources (e.g. the TES microcalorimeters in the Athena X-ray Integral Field Unit instrument).
Within a research activity aimed at developing a NTD-Ge cryogenic microcalorimeter array detector for high resolution (about 50 eV @ 60 keV) detection of hard X rays (20 keV < E < 100 keV), we have set up an electroplating process to deposit high thickness (> 60 m) bismuth layers suitable for effective high energy photon absorption.
In this work we describe the fabrication of bismuth absorbers designed to be integrated on arrays of NTD-Ge sensors and discuss results from preliminary characterization.
|Less than 5 years of experience since completion of Ph.D||Y|
|Student (Ph.D., M.Sc. or B.Sc.)||Y|