HowTo&Troubleshooting

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Select a different grating of the Monochromator

Ask the assistance of a beamline scientist the first time you need to do this procedure, since you can seriously damage the grating if you do not follow the procedure properly!

Check here the Energy Ranges of the four spherical gratings of the Monochromator: The Beamline
 

     
1 MonoGratingNumber.vi Check that this VI is not operative (stop all the scanning VI which read the energy such as scan energy, ScanXPS..). The arrow should be white. If you see that the arrow is white, it is OK. If the arrow appears broken, check again, find and stop the VI still running.
2 MainPanel.vi CLOSE FRONT END
3 MANUAL OPERATION Go next to the Monochromator Chamber (big Chamber along the beamline). You will find on the floor below the chamber, a small controller with a black wheel, where LIFT and DOWN positions are marked.
The pressure meter is localized at the feet of the monochromator, on the left (SISSI beamline side), towards the front end.
Localize the linear motion.

Follow these steps:

STEP0: check that  the pressure meter reads 4.5.

STEP1: LIFT the piston by rotating slowly the small wheel from down to lift position, until the end (there is a small offset: you have to go a little bit more than the lift position until the wheel will stop), and checking the pressure on the manometer (from 4.5 bar to 0 bar). At the end of this operation visually check that the piston has lifeted and that the pressure meter reads 0.

STEP2: MOVE manually the grating by moving the linear motion from the position of SG2 to the position of SG3 (as marked on the linear motion scale). The bellow can make some noise, do not worry.

STEP3: Push DOWN again the piston by rotating slowly the small wheel from lift to a little bit before the down position (on the line marked manually) checking the pressure on the manometer (from 0 to 4.5 bar). DO NOT GO BEYOND THIS POSITION!!!! GOING ABOVE 4.5 bar can damage seriously the monochromator and the beamline vacuum. At the end of this operation visually check that the piston is down again.
4 MonoGratingNumber.vi Select the grating clicking on the grey rectangle with the name of the grating (in the picture SG2) and choosing the grating from the drop-down menu which will appear [e.g. SG3 (5)]and Press =>
     
6 Monohome GALIL.vi

STEP1: Select pre-mirror angle, run the VI (press =>) and then press GO (wait that the red light becomes green).    This may take several minutes (typically 2 minutes). If, after 10 minutes the Mirror is still moving, stop the MONO HOME VI and try to do the Mono homing of the mirror again. {ONLY FOR BACH BL STAFF: The last time that the mirror angle was stuck during a mono home SG3->SG2: start: MA=87.43, STEP=311801. The position were was stuck: energy=542.8, MA=86.988, Step=274246}      Sg2->Sg1 (After M energy reads -82 eV)

You have to move the mirror (first) and the grating (second) in order to reach the limit switch. Don't move the grating first, otherwise you may crash the monochromator optics.

NOTE: Sg3->Sg2 (After M energy reads +218.72 eV; Mirror Angle=85.823; Mirror Position=174717)
Sg2->Sg3 (After M energy reads +422.24 eV; Mirror Angle=85.8; Mirror Position=174739)

STEP2: Select grating angle, run the VI (press =>) and then press GO (wait that the red light becomes green). This may take several minutes (typically 1 minute for G). If, after 10 minutes the Grating is still moving, stop the MONO HOME VI and try to do the Mono homing of the Grating again. At the end of this operation, read the energy (ENERGY CONTROL GALIL VI): both grating and pre-mirror will be at about 84 and the energy reads -348 eV (with SG3) or -326 (with SG2).      NOTE: Sg3->Sg2 (After G energy reads -326 eV; Grating Angle=84.045; Grating Position=58727); Sg2->Sg3 (After G energy reads -348 eV; Grating Angle=84.097; Grating Position=58730)
7 MainPanel.vi Select the new grating clicking on the rectangle with the name of the grating and choosing the grating from the drop-down menu which will appear [e.g. SG3 (5)]and Press =>

Read the energy. If mono homing is ok you should read ABOUT -348 eV or -326

Select the energy (in the range of the grating you have selected!) you want to use and then press MOVE (this may take several minutes!!!)
8 SetEneryandUndulator.vi Select the new grating in the Calculator field
9 MotorControl.VI

CHACK POSITION ON THE CERAMIC at y=(26.1 or) 27 (the beam on the sample  is usually left bottom edge of the marker on the ceramic)

Press ==>.

Select: Element: POSTHORA and Action: Pitch

Read. You should read a value between -45000 and -48000.

Move to the value corresponding to the new garting selected.
GRATING NEW
 		 OLD VALUES
SG1-XPS -44900 (check) -48800
SG2-XPS -48300/V=-7500 -51300
SG3-XPS -46000/V=-7800 -50400
SG4-XPS   -46150? Value to be checked

 
10 MainPanel.VI OPEN FRONT END
Last Updated on Thursday, 13 September 2018 12:57