Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/docs/documents/CAL-SRN-0074-1-0.ps.gz Дата изменения: Fri May 4 16:17:44 2001 Дата индексирования: Mon Oct 1 21:57:21 2012 Кодировка: Поисковые слова: dark energy

XMM­Newton CCF Release Note
XMM­CCF­REL­74
EPIC Dark Frames
D Lumb
April 27, 2001
1 CCF components
Name of CCF VALDATE List of Blocks
changed
CAL VERSION XSCS flag
EMOS1 DARKFRAME 0007.CCF 2000­01­01 DARKFRAME CCDn NO
OFFSET CCD1
EMOS1 DARKFRAME 0007.CCF 2000­01­01 DARKFRAME CCDn NO
OFFSET CCD1
2 Changes
It seems there are low level pixel defects which affect locally the energy scales, that are not corrected
for by the on­board offset vectors. In trying to establish the limits to low energy response, it seems
important to make a correction for these.
As a result changes to the the dark frame files to include a higher precision were made. Several
10's of diagnostic image files from early in the mission were median filtered to remove cosmic ray
artefacts, and teh mean pixel by pixel offset value calculated. Keyword ALGOID allows to check
whether CAL needs to divide by 100 or not to gain appropriate precision.
Fixed SPR 1987 on loction of Right Hand Side patched column for window modes in the as­used
on­board offset tables.
Added in the TIMING mode offset data as newly compiled by A Tiengo for the fixed table usage
­ this should apply the as­calculated offsets in early mission phase as well
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XMM­Newton CCF Release XMM­CCF­REL­74 Page: 2
3 Scientific Impact of this Update
4 Estimated Scientific Quality
Depending on the number of usable image frames used the typical error on determining a pixel offset
is about 1 ­ 2 electrons. This implies an X­ray photon energy bias error of order 5 eV.
5 Expected Updates
Due to developing low level defects, this file set may need to be updated with time