mtilt1 Optimisation 

1. Principle

It consists in optimising the horizontal and vertical displacement of the exit beam, by means of adjusting the mtilt1 position of the 2nd crystal.


  • Install the two-head CCD camera. Check the settings in ‘Parameters’:
    • Pixels :8.3
    • Large head : demagnification 0.841
    • Small head :demagnification 2.926
    • With these settings the beam position values are in microns.
  • Center the beam and choose the appropriate exposure time (the same for low energy (ex.8 keV ) and high energy (ex. 25 keV).
  • The procedure is iterative. In order to find a minimum in horizontal and vertical beam displacement as a function of mtilt1 repeat the following steps:
    1. at a given position of mtilt1 measure the beam position i.e. the y and z coordinates for 8 keV and then for 25 keV.
    2. change the mtilt1 and repeat the measurement for 8 keV and 25 keV.
    3. Calculate the difference dY (E2 –E1) and dX (E2-E1).
    4. Repeat steps 1and 2 until dY and dX is minimum.


2. Automatic Optimisation

*using mono application :

  • in “tilt1 calibration settings” set tilt1 range and the two energies (ex. 15 and 30 keV)


*using Spec macro :

  • mono_tunetilt1 tilt1(start) tilt1(end) n0 of points Energy1[keV] Energy2
    > ex: mono_tunetilt1 100 500 10 15 30


Principle of Energy Calibration

The monochromator energy calibration is based on the absorption edge fine structure or inflection point (Cu, Ge, Zr, Mo…).

  1. Place an absorber foil in front of the Si-PIN diode.
  2. > monooff
  3. Put the monochromator near to the expected position of the absorption edge.

  4. Ex: for Cu K-absorption edge, mono around 12.7 degrees.
    > mv mono 12.7
  5. > dscan mono –0.1 0.1 100 0.1
    (in the case of having “lost” the monochromator, a greater angular interval is necessary)
  6. move mono for e.g. to 12.7058 corresponding to the position of the fine structure ‘dip’ in the K-absorption edge:
    > mv mono 12.7058
  7. > monoon
  8. > setE 8.9825
    ( the mono is set automatically to the corresponding angle of 12.7167)
  9. to the Spec question “Change SpecMAXE…?” answer :YES