Difference between revisions of "Radiation environment"

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[[Category:Ground Segment and Operations]]
[[Category:Ground Segment and Operations]]

Revision as of 11:49, 21 September 2012

(Note: Adapted from Planck Collaboration 2011, A&A 536, A1)

The Standard Radiation Environment Monitor on board Planck (SREM, Buehler et al. 1996) is a particle detector which is being flown on several ESA satellites. The SREM consists of several detectors sensitive to different energy ranges, which can also be used in coincidence mode. In particular, the SREM measures count rates of high energy protons with E>20 MeV, electrons with E>0.5 MeV and Ions with 150 MeV < E < 185 MeV.

Particle fluxes measured by the SREM on board Planck are shown in Fig. 8. The radiation environment of Planck is characterised by the current epoch near the minimum in the solar cycle. As a consequence, the particle flux is dominated by Galactic cosmic rays, rather than by the solar wind. The time evolution of the SREM measurements is well correlated with that of identical units flying simultaneously on other satellites (e.g., Herschel, Rosetta) and with indicators of Galactic cosmic rays, and is anti-correlated with solar flare events and with the solar cycle (Fig. 8). More importantly for Planck, the SREM measurements are very well correlated with the heat deposition on the coldest stages of the HFI, and with glitch rates measured by the detectors of HFI. A more detailed interpretation of these data is provided in Planck HFI Core Team (2011a).

Space Radiation Environment Monitor

European Space Agency

(Planck) High Frequency Instrument