General CL capabilities
- Looking at the detector and grating efficiency curves (see links, below) indicates that spectra can be collected over a range of about 200-1000 nm, and imaging using PMT1 and PMT2 can cover the range 200-850 nm. The VP detector is sentitive to light in the 300-650 nm range.
Grating and detector details
- The CL spectrometer has three diffraction gratings, with 300, 1200, and 1800 lines/mm. Click on each to see their diffraction efficiency curves. All are blazed at 500 nm. On two of the graphs there are TM and TE lines, which stand for Transverse Magnetic and Transverse Electric. They refer to polarized light, with the electric vector either perpendicular to the grating surface (TM) or parallel (TE). Because our system provides more or less unpolarized light, that is the curve to pay attention to. The graph for the 1200 grating doesn’t have an unpolarized line, but it goes exactly between the two polarized lines.
- There are four detectors that can be used for CL work: PMT1 for basic panchromatic or color filter imaging, PMT2 for spectrum band imaging, the CCD for collecting spectra, and the VP detector in the SEM chamber. Their light detection efficiencies vary with wavelength, click on each to see their detection efficiency curves. Note that PMT1 and PMT2 are the same kind of detector, just in different places. That’s why the sensitivity curves are the same.
