Electron Microprobe Standard Block
Starting up the Electron Microprobe
UHH / HVO Electron Microprobe Home Shutting down the Electron Microprobe Electron Microprobe Manual

CRYSTAL FLIPPING

DO NOT ATTEMPT TO FLIP CRYSTALS UNLESS YOU HAVE BEEN SHOWN HOW TO DO THIS. DAMAGE TO THE SPECTROMETER CAN RESULT.

The moveable spectrometers (scanners) have two crystals each. The crystals are mounted 180 degrees apart on a rotating shaft and either crystal is selected by flipping the crystal around the shaft using the large knob on the spectrometers. Only one crystal per spectrometer can be used for any given analytical set-up and the crystals cannot be flipped during analysis (this is the one drawback of having an older probe, newer probes have computer controlled flipping of spectrometers). In our analytical configuration the three moveable spectrometers use the ADP, TAP, and LIF crystals (on spectrometer numbers 2, 3, and 1, respectively). In some cases it may be desirable to have an additional LIF crystal on a spectrometer, in which case the crystal on spectrometer 2 would be flipped from an ADP to a LIF crystal.

The available crystals on moveable spectrometer 1 are LIF and PET. Moveable spectrometer 2 contains crystals ADP and LIF and moveable spectrometer 3 contains crystals TAP and ADP.

Before flipping crystals, check to see if the crystals are already in position by noting the position of the index marked on the crystal flipping knob (upper right hand corner of the spectrometer). It should be aligned with the mark on the spectrometer??

Flipping a Crystal

  1. Drive the spectrometer to its upper limit using the Park Spectrometer command located in the JoyWin Program.
  2. Flip the crystal on the desired spectrometer.

  3. Use the Joystick to manually drive the spectrometer ?? down a bit from 37000 (parked). You will hear a click as the crystal flipper gate locks the index and knob in position. Continue to turn the odometer down about 100 units past this point.
  4. Drive the spectrometer to roughly 35000. If the spectrometer and the computer don't show the exact same numbers, you may have to restart the JoyWin Program??
  5. Set the Attenuator, Focal Circle, and Crystal Adjust to the values of the crystal you just flipped. Use the settings from the Spectrometer Book.
  6. Turn the Attenuator (on the X-RAY Console) to the desired spectrometer number for the setting of the new crystal.
  7. Set the focal circle and crystal adjust knobs on the spectrometer to the settings for the new crystal listed in the book.

  8. It is a good idea to restandardize those elements measured on a crystal that has just been flipped, in case there is a slight difference in the alignment or wavelength settings between the present and previous alignments.