Cathodoluminoscope

Location: JSC 3C26A

The cathodoluminoscope is a useful instrument for characterizing the structure and nature of certain elements at microscopic scales. The scope is a basic microscope with an electron gun (cathode ray source) and an enclosed stage that may be evacuated. A sample is placed in the stage, and the electron beam is directed on the sample with magnets (the electrons leave the negatively charged cathode and travel across the stage, which is positively charged). If the sample contains elements that are emit visible light when excited by the beam, then these may be observed optically. Additionally, our luminoscope has an aLuminoscopettached spectrometer and digital processing system, that permits characterization of the emitted light and identification of the emitting elements.

The instrument is similar to a traditional (cathode-ray) television set or monitor (CRT). In a CRT, an electron gun emits electrons from the back towards the front of an evacuated tube. The electrons are deflected by a magnet in the middle of the tube. The front of the tube is coated with materials that become excited when struck by the electrons, producing visible light. This happens repeatedly and quickly over the screen to produce a single image.

Our cathodoluminoscope is used for characterizing the distribution and movement of emitter atoms in minerals. Natural materials that typically play host to abundant emitters include calcite, zircon, allanite, xenotime, and apatite, although any mineral may host emitting elements to one degree or another. We also produce synthetic minerals with emitters to observe changes in their distribution with other parameters.