Controlling the Swift XRT CCD temperature with passive cooling

J. A. Kennea, D. N. Burrows, A. Wells, C. Pagani, J. E. Hill, J. L. Racusin, D. Morris, S. Hunsberger, A. F. Abbey, A. Beardmore, S. Campana, M. Chester, G. Chincarini, G. Cusumano, N. Gehrels, O. Godet, T. Mineo, V. La Parola, V. Mangano, A. MorettiJ. Nousek, J. Osborne, K. Page, M. Perri, G. Tagliaferri, F. Tamburelli

Research output: Contribution to journalConference articlepeer-review

5 Scopus citations


The Swift X-ray Telescope (XRT) is a CCD based X-ray telescope designed for localization, spectroscopy and long term light curve monitoring of Gamma-Ray Bursts and their X-ray afterglows. Shortly after launch there was a failure of the thermo-electric cooler on the XRT CCD. Due to this the Swift XRT Team had the unexpected challenge of ensuring that the CCD temperature stayed below -50C utilizing only passive cooling through a radiator mounted on the side of the Swift. Here we show that the temperature of the XRT CCD is correlated with the average elevation of the Earth above the XRT radiator, which is in turn related to the targets that Swift observes in an orbit. In order to maximize passive cooling of the XRT CCD, the XRT team devised several novel methods for ensuring that the XRT radiator's exposure to the Earth was minimized to ensure efficient cooling. These methods include: picking targets on the sky for Swift to point at which are known to put the spacecraft into a good orientation for maximizing XRT cooling; biasing the spacecraft roll angle to point the XRT radiator away from the Earth as much as possible; utilizing time in the SAA, in which all of the instruments on-board Swift are non-operational, to point at "cold targets"; and restricting observing time on "warm" targets to only the periods at which the spacecraft is in a favorable orientation for cooling. By doing this at the observation planning stage we have been able to minimize the heating of the CCD and maintain the XRT as a fully operational scientific instrument, without compromising the science goals of the Swift mission.

Original languageEnglish (US)
Article number589816
Pages (from-to)1-11
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2005
EventUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XIV - San Diego, CA, United States
Duration: Aug 1 2005Aug 3 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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