RADIATION MONITORING DEVICES, INC. — National Aeronautics and Space Administration SBIR Phase I: S1

Description

The next generation of wide-field survey instruments with improved angular and energy resolution for research into astrophysical transient X-ray phenomena is currently under development. A scalable detector plane architecture has been developed at Harvard using CZT detector arrays for use in high resolution coded-aperture telescopes.Despite decades of research, the yield of device grade CZT is still quite low. In addition, internal defects cause spatial distortions in images. To meet the needs of hard X-ray astronomy a lower cost, more uniform and more readily available alternative to CZT is desirable.Thallium bromide (TlBr) has higher density and atomic number than CZT and therefore higher stopping power at hard X-ray energies. TlBr has a low melting point (460 deg;C, compared to ~ 1100 deg;C for CZT) and cubic crystal structure and can be grown from the melt by low cost techniques. As a result, TlBr has the potential to be a more efficient, lower cost alternative to CZT in the detector plane architecture developed by Harvard for use in high resolution coded-aperture telescopes.