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تسجيل مستخدم جديدUsing ACIS on the Chandra X-ray Observatory as a particle radiation monitor
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The Advanced CCD Imaging Spectrometer (ACIS) is one of two focal-plane instruments on the Chandra X-ray Observatory. During initial radiation-belt passes, the exposed ACIS suffered significant radiation damage from trapped soft protons scattering off the x-ray telescopes mirrors. The primary effect of this damage was to increase the charge-transfer inefficiency (CTI) of the ACIS 8 front-illuminated CCDs. Subsequently, the Chandra team implemented procedures to remove the ACIS from the telescopes focus during high-radiation events: planned protection during radiation-belt transits; autonomous protection triggered by an on-board radiation monitor; and manual intervention based upon assessment of space-weather conditions. However, as Chandras multilayer insulation ages, elevated temperatures have reduced the effectiveness of the on-board radiation monitor for autonomous protection. Here we investigate using the ACIS CCDs themselves as a radiation monitor. We explore the 10-year database to evaluate the CCDs response to particle radiation and to compare this response with other radiation data and environment models.
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The Chandra X-ray Observatory was launched almost 19 years ago and has been delivering spectacular science over the course of its mission. The Advanced CCD Imager Spectrometer is the prime instrument on the satellite, conducting over 90% of the obser
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