I. Table for energy scans

One can perform energy scans using tabulated data of the monochromator positions under the same experimental conditions. This accelerates the energy change procedure. To this end:

  • In “SpecGUI’’ window (Fig. 1) click on “Advance” box to open the “Advance mono settings” window (Fig. 3) .
  • Put the new parameters in: “Monochromator Options”
    • Choose the monochromator crystal {default : Si (111)}
    • Tuning method - Table
    • Scan mode - Continous
    • Counter – set the detector (nova or novb)

 

“Monochromator Calibration”

Setup tuning parameters:

  • Time per tuning point (sec) – sets the integration time.
  • Relative start (arcsec) – start position.
  • Relative stop (arcsec) – end position.
  • Number of tuning points – number of points in scan.
  • Low energy threshold – energy value below which the detuning coefficient is constant.
  • Cst detuning for low energy – detuning coefficient below threshold
  • Detuning (% of fwhm) – sets the value of the second crystal angular offset depending on the rocking curve width.

Build the position table in the Tilt2 area:

  1. Put in the Start (keV), End (keV) values for energy, and number of points -Nb.Points.
  2. Click on Build Table

The program will make energy scan with a fine tuning of the second crystal to a predefined value of Detuning value. After the table is built, one can use it to make different scans within the tabulated interval of energies. The energy scan intervals can be different from these in the table. In this case the program will interpolate the missing point using the nearest tabulated data.

 

In order to perform the energy scan:

Apply the standard commands (ascan, dscan, etc.) to mkev, mwave, and mono pseudo-motors.

II. Automatic optimisation mtilt1 angle.

In “SpecGUI’’ window (Fig. 1) click on “Advance” box to open the “Advance mono settings” window (Fig. 3).

Put in the new parameters in:“Monochromator Options”

  • Choose the monochromator crystal {default : Si (111)}
  • Tuning method - Scan
  • Scan mode - Continous
  • Counter – set the detector (nova or novb)

 

“Monochromator Calibration”

Setup tuning parameters:

  • Time per tuning point (sec) – sets the integration time.
  • Relative start (arcsec) – start position.
  • Relative stop (arcsec) – end position.
  • Number of tuning points – number of points in scan.
  • Low energy threshold – energy value below which the detuning coefficient is constant.
  • Cst detuning for low energy – detuning coefficient below threshold
  • Detuning (% of fwhm) – sets the value of the second crystal angular offset depending on the rocking curve width.

 

In the box: mtilt1 calibration settings:

  • Set Low Energy value and High Energy value in keV.
  • Go back to “Monochromator Calibration”
  • In Tilt1: Set Rel. Start and Rel end values for the mtilt1 motor and the Nb. of points
  • Click on Tune Tilt1