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Electrode level Monte Carlo model of radiation damage effects on astronomical CCDs

Prod'homme, T.; Brown, A. G. A.; Lindegren, Lennart LU ; Short, A. D. T. and Brown, S. W. (2011) In Monthly Notices of the Royal Astronomical Society 414(3). p.2215-2228
Abstract
Current optical space telescopes rely upon silicon charge-coupled devices (CCDs) to detect and image the incoming photons. The performance of a CCD detector depends on its ability to transfer electrons through the silicon efficiently, so that the signal from every pixel may be read out through a single amplifier. This process of electron transfer is highly susceptible to the effects of solar proton damage (or non-ionizing radiation damage). This is because charged particles passing through the CCD displace silicon atoms, introducing energy levels into the semiconductor band gap which act as localized electron traps. The reduction in charge transfer efficiency (CTE) leads to signal loss and image smearing. The European Space Agency's... (More)
Current optical space telescopes rely upon silicon charge-coupled devices (CCDs) to detect and image the incoming photons. The performance of a CCD detector depends on its ability to transfer electrons through the silicon efficiently, so that the signal from every pixel may be read out through a single amplifier. This process of electron transfer is highly susceptible to the effects of solar proton damage (or non-ionizing radiation damage). This is because charged particles passing through the CCD displace silicon atoms, introducing energy levels into the semiconductor band gap which act as localized electron traps. The reduction in charge transfer efficiency (CTE) leads to signal loss and image smearing. The European Space Agency's astrometric Gaia mission will make extensive use of CCDs to create the most complete and accurate stereoscopic map to date of the Milky Way. In the context of the Gaia mission CTE is referred to with the complementary quantity charge transfer inefficiency (CTI = 1-CTE). CTI is an extremely important issue that threatens Gaia's performances: the CCDs are very large so that the electrons need to be transferred a long way; the focal plane is also very large and difficult to shield; the mission will operate at second Lagrange point where the direct solar protons are highly energetic (penetrating) and the science requirements on image quality are very stringent. In order to tackle this issue, in depth experimental studies and modelling efforts are being conducted to explore the possible consequences and to mitigate the anticipated effects of radiation damage. We present here a detailed Monte Carlo model that has been developed to simulate the operation of a damaged CCD at the pixel electrode level. This model implements a new approach to both the charge density distribution within a pixel and the charge capture and release probabilities, which allows the reproduction of CTI effects on a variety of measurements for a large signal level range in particular for signals of the order of a few electrons. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
instrumentation: detectors, methods: analytical, methods: data, analysis, methods: numerical, space vehicles, astrometry
in
Monthly Notices of the Royal Astronomical Society
volume
414
issue
3
pages
2215 - 2228
publisher
Wiley-Blackwell
external identifiers
  • wos:000292977600032
  • scopus:79959375479
ISSN
1365-2966
DOI
10.1111/j.1365-2966.2011.18537.x
language
English
LU publication?
yes
id
c6ebb266-583b-4c07-9042-b894fbba0703 (old id 2071997)
date added to LUP
2011-08-29 09:26:23
date last changed
2017-09-03 03:08:25
@article{c6ebb266-583b-4c07-9042-b894fbba0703,
  abstract     = {Current optical space telescopes rely upon silicon charge-coupled devices (CCDs) to detect and image the incoming photons. The performance of a CCD detector depends on its ability to transfer electrons through the silicon efficiently, so that the signal from every pixel may be read out through a single amplifier. This process of electron transfer is highly susceptible to the effects of solar proton damage (or non-ionizing radiation damage). This is because charged particles passing through the CCD displace silicon atoms, introducing energy levels into the semiconductor band gap which act as localized electron traps. The reduction in charge transfer efficiency (CTE) leads to signal loss and image smearing. The European Space Agency's astrometric Gaia mission will make extensive use of CCDs to create the most complete and accurate stereoscopic map to date of the Milky Way. In the context of the Gaia mission CTE is referred to with the complementary quantity charge transfer inefficiency (CTI = 1-CTE). CTI is an extremely important issue that threatens Gaia's performances: the CCDs are very large so that the electrons need to be transferred a long way; the focal plane is also very large and difficult to shield; the mission will operate at second Lagrange point where the direct solar protons are highly energetic (penetrating) and the science requirements on image quality are very stringent. In order to tackle this issue, in depth experimental studies and modelling efforts are being conducted to explore the possible consequences and to mitigate the anticipated effects of radiation damage. We present here a detailed Monte Carlo model that has been developed to simulate the operation of a damaged CCD at the pixel electrode level. This model implements a new approach to both the charge density distribution within a pixel and the charge capture and release probabilities, which allows the reproduction of CTI effects on a variety of measurements for a large signal level range in particular for signals of the order of a few electrons.},
  author       = {Prod'homme, T. and Brown, A. G. A. and Lindegren, Lennart and Short, A. D. T. and Brown, S. W.},
  issn         = {1365-2966},
  keyword      = {instrumentation: detectors,methods: analytical,methods: data,analysis,methods: numerical,space vehicles,astrometry},
  language     = {eng},
  number       = {3},
  pages        = {2215--2228},
  publisher    = {Wiley-Blackwell},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {Electrode level Monte Carlo model of radiation damage effects on astronomical CCDs},
  url          = {http://dx.doi.org/10.1111/j.1365-2966.2011.18537.x},
  volume       = {414},
  year         = {2011},
}