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T-ReCS Properties

T-ReCS Optical Properties

The optical elements of T-ReCS (e.g. windows, filters, gratings and slits) are described in detail on the T-ReCS instrument pages

T-ReCS Detector Properties

v3.1 of the T-ReCS ITC includes the most recent detector characteristics derived from the pre-ship Acceptance Testing. These tests indicated an "extra low frequency noise" (ELFN) which effectively multiplies the Poisson noise on the source and background flux by a factor of ~4. Further measurements will be made during instrument commissioning.

The individual exposure (a.k.a "frame") time is fixed and not a user-changeable parameter (unlike the total integration time). During normal operation the frame time is set to optimally fill the wells and achieve sensitive performance. For the purposes of ITC calculation the frame times used are somewhat arbitrarily set to 0.02, 0.1 and 0.5s for imaging (all filters), low-resolution spectroscopy (10 and 20um) and high-resolution spectroscopy, respectively.


Spectroscopic resolution and sampling

The ITC samples the spectral distributions at 10nm. However, the input source, background and transmission spectra may have a lower resolution, see description of the spectral distributions used by the ITC. Therefore, the output spectra from the ITC may not correctly reflect the resolution that can be achieved with T-ReCS.

Last update August 28, 2001; Phil Puxley