Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://xmm.vilspa.esa.es/user/socpub/ccd_review/node6.html
Дата изменения: Fri Aug 30 15:55:09 1996 Дата индексирования: Tue Oct 2 11:52:40 2012 Кодировка: Поисковые слова: ngc 891 |
Conventional CCDs are illuminated through a front-surface electrode structure which may be m thick. This severely limits the sub-keV detection efficiency. They also have a detection volume defined by the depletion layer depth of m. This should be compared with, for example, the 1/e attenuation length for 6keV photons which is m; hence CCD sensitivity falls rapidly with increasing energy.
The use of back-illumination technology to enhance soft X-ray response has benefitted from developments for similar requirements to minimize the entrance dead layer thickness for blue/UV wavelengths. However the development of CCDs with deeper depletion depths to maximize the detecting volume has been a pre-occupation unique to the X-ray community. (This method would be useful for the near-IR wavelenghts, but has not been widely adopted)