Now that the SEM is finally setup and working properly, all the additional bits and pieces can be installed. First to go is the Gatan ChromaCL cathodoluminescence system. It is a neat little detector that is attached through the large WDS port on the back right corner of the chamber. The detector is a machined parabolic mirror that is inserted between the objective lens and the sample. It is about 10mm thick, has 1mm clearance between the top of the detector and the bottom of the objective lens and 1mm focal length to the sample surface. This means that everything is very tight in the chamber when it is in use. The BSE detector needs to be removed from the objective lens prior to inserting the CL detector. The light collected by the mirror is sent to a diffraction grating where it is separated into the visible spectrum and a PMT detects red, green and blue signals which are sent to the display. The system is capable of live, real color imaging of a cathodoluminescent sample. The installation went smoothly, but a minor defect was found in the digital images collected by the system. The first line of pixels is not in the correct position and is clearly shifted relative to the rest of the image. Our service engineer hadn't seen this problem before and his changes to the system didn't fix it so he was going to forward test images to the applications engineers to see what solution they could come up with.
In the meantime, here's an image of a zoned mineral grain taken with the new system.