The Open UniversitySkip to content

Space radiation environment effects on X-ray CCD background

Hall, David J. and Holland, Andrew (2010). Space radiation environment effects on X-ray CCD background. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 612(2) pp. 320–327.

Full text available as:
PDF (Accepted Manuscript) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (3MB) | Preview
DOI (Digital Object Identifier) Link:
Google Scholar: Look up in Google Scholar


Charge coupled devices (CCDs) are often employed as the detector of choice for observing X-rays in space. The instrument background experienced in orbit has a major impact on the overall sensitivity of the camera system. The instrument background for the European Space Agency X-ray Multi Mirror (XMM-Newton) mission was found to be much greater in orbit than that originally predicted prelaunch, the reasons for which still being up for discussion. The Geant4 toolkit provides a framework for Monte Carlo simulations in a variety of areas in science and is used here to simulate the instrument background for several CCD based detectors in-orbit in order to gain a further insight into the formation of the instrument background continuum. The missions discussed in this paper include the ESA XMM-Newton mission, the NASA Swift mission and the Japanese Space Agency Suzaku mission. These three missions allow a comparison between the effects of both the mission orbit and the detector construction on the instrument background count-rate. Analysis of the results from the simulation lead to the conclusion that knock-on electrons, produced when protons pass through the shielding, dominate the instrument background continuum at the XMM-Newton Highly Elliptical Orbit (HEO) with a perigee and apogee of approximately 7000 and 120 000 km respectively, forming an additional background component not considered in the pre-launch study. The surface properties of the detector and shielding have the greatest impact on the level of the instrument background due to the interaction length of the knock-on electrons produced. At the Low Earth Orbit (LEO) of Swift and Suzaku at approximately 600 km, the impact of the knock-on electrons is reduced due to the differing in-flux of protons, and the form of the instrument background can vary greatly with the detector construction. The inconsistencies between this study and the pre-launch simulations are discussed. Sensitivity considerations regarding the instrument background are deliberated with a view towards future missions.

Item Type: Journal Item
Copyright Holders: 2010 Elsevier B.V.
ISSN: 0168-9002
Keywords: Instrument background; XMM; Suzaku; Swift; XEUS/IXO; Geant4; CCD X-ray spectrometer; Sensitivity; PHOTON IMAGING CAMERA; XMM-NEWTON
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Research Group: Centre for Electronic Imaging (CEI)
Item ID: 20626
Depositing User: Karen Guyler
Date Deposited: 12 Mar 2010 14:54
Last Modified: 09 Dec 2018 01:09
Share this page:


Altmetrics from Altmetric

Citations from Dimensions

Download history for this item

These details should be considered as only a guide to the number of downloads performed manually. Algorithmic methods have been applied in an attempt to remove automated downloads from the displayed statistics but no guarantee can be made as to the accuracy of the figures.

Actions (login may be required)

Policies | Disclaimer

© The Open University   contact the OU