New solar broad-band Hard X-ray Spectrometer: First results

The scientific and operational aims of the Czech-made Hard X-Ray Spectromet er (HXRS) launched onboard the U.S. Department of Energy Multispectral Ther mal Imager satellite (MTI), on 12 March 2000 are discussed. The principal o perating characteristics of the instrument such as the temporal resolution, energy band selection, spectral sensitivity, and the in-flight calibration procedure are described as well as the technical details of the spectromet er including detectors, shielding (against charged particles) and electroni c design. The MTI host satellite and its orbit are briefly described. Recen t observations by the 3 GHz Ondrejov radiometer are compared with HXRS data to demonstrate one example of the HXRS data utilization: the temporal rela tion between hard X-rays and radio emission. These results show relatively long time delays (2-14 s) of the GHz broadband radio pulses relative to the hard X-ray emission peaks. Access to the HXRS data base via the Internet i s provided.