CCD sounding rocket observations of the soft x-ray background

摘要

Results of the first CCD observations of the x-ray background between 0.2 and 10 keV are presented. Data were obtained from individual sounding rocket flights on May 22, 1995 from White Sands, New Mexico and on October 25, 1995 from Woomera, Australia. The target for the second flight was a bright region of the 3/4 keV x-ray background centered at 0 degree longitude and minus 15 degrees latitude in galactic coordinates. Covering approximately 1800 square degrees, this feature dominates all-sky surveys below the galactic plane from 0.5 to 1.5 keV. This data is compared with data from a dim region of the 3/4 keV x-ray background in the constellation Draco, obtained on the first flight. The detector for these flights was a thin gate CCD built by EEV and designed to maximize x-ray response below 0.75 keV without adopting a backside illumination scheme. Improved quantum efficiency over conventional x-ray CCDs above 1 keV was also achieved due to the high resistivity (1500 ohm-cm) of this device. This type of CCD was flown on the CUBIC experiment in November 1996. Similar devices are also scheduled to be launched on Leicester University's spectrum X/JET-X and XMM/EPIC instruments.