Users guide

All information for users can be found in the user guide webpages applicable for all beamlines.

Useful programs for data processing

Powder diffraction data can be integrated using FIT2D or DIOPTAS.

Integration of single-crystal data can be performed with CrysAlisPro.

Useful commands on the beamline

exp

Open the bliss session to collect data/ make scans

shexp.open()

To open the shutter

shexp.close()

To close the shutter

ruby

To go to the “camera” position: to measure pressure

beam

To go to the “beam” position: to collect X-ray data

dscan(motor, -n, n, step, sec)

  • Motor: ceny for the horizontal pos// dacz vertical one
  • -n, n: starting and final position. In mm
  • Step: number of points taken for the scan. Usually 40
  • Sec: acquisition time. Use 0.1

goto_cen()

Go to the centre of the scan

goto_peak()

Go to the peak of the scan

umv(motor, ± number)

  • Move the sample stage in the given (number) position
  • Motors: dacz, ceny, IVU20c, pace1_axis, pace2_axis

umvr(motor, ±number)

Move the sample stage, relatively, of number millimetres

tweak(motor, 0.1) than + or -

Move the selected motor of 0.1 mm in + or -. Pressing again + or – will move again. Press any other key to exit.

wa()

Position of all motors

name of the motor

Give the position of the chosen motor

POS1.update()

Save the position in which you are as POS1 (same for POS2, POS3)

POS1.go()

Go in POS1.

oscillation(-32,32,0.5,0.2)

Collect data: from -32° to +32 °, step 0.5°, counting 0.2 second/frame

oscillation.run()

Recall the previous used data collection

oscillation.one(-1,1,1.5)   

take only one frame, from -1° to +1°, counting 1.5 seconds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  Mesh 2D

  oscillation.dmesh(ceny, -0.1, +0.1, 2, dacz, -0.1, +0.1, 2)

  In this way the 9 measures will be collected accordingly to the following grid

  NB looking at the camera ceny is increasing from the right to the left; dacz from the bottom to the top;

 the point N5 will be in the centre (ceny=0, dacz=0)

  • 9
  • 8
  • 7
  • 6
  • 5
  • 4
  • 3
  • 2

 Please note that there is little sense to create a grid with step lower than the size of the beam

 

   

     LIST OF USEFUL MOTORS

IVU20c

GAP; for SC between 12 and 12.6, for powder between 7.05 and 7.21

ceny

Move the sample stage along the horizontal direction

dacz

Move the sample stage along the vertical direction

cenx

Move the sample stage on the beam direction

decx

Detector-sample distance, usually 180 mm for single crystal, 250 for powder

dacrot

Control the omega rotation of the sample stage

shexp

Move the beam stopper

la

Change the power of the laser for ruby measurement

pace1_axis

Control the pressure of the membrane (gate pace1)

pace2_axis

Control the pressure of the membrane (gate pace2)

Increasing membrane pressure

pace1 or pace2

To see the pressure (P) of pace1 or pace2. You will see two things:

input: pace1_in@ n bar      which is the pressure in the tank (same if pace2 is typed)

output: pace1_out@ n bar  which is the pressure in the membrane

pace1.setpoint= n

To set the P of pace1 to n. While pressure increases you can type other commands

umv(pace1_axis, n)

To set the P of pace1 to n. While pressure increases you can’t type other commands

n has to be >0.1 bar

pace1.ramprate= n

It changes the ramp rate to n bar/min (if 0 is set the speed is maximum)

 

Troubleshooting 

Zaber console crashes: close the window and restart it. Choose COM1 as the device to connect. Change the units to mm for motors. Then make a small movement for each of the motors (0.01 moves) to see the absolute values of the microscope.Troubleshooting

Error value out of range when measuring ruby: the beam is too intense and saturates, so either reduce the acquisition time, move slightly off the ruby, or reduce the laser power by typing umv la 0.64 in the exp window. Check first the value of la before changing it by typing wa. Lower values reduce the intensity of the beam, while higher values increase it.

PRL system crashes: Restart the PRL program. Need to do the calibration after restart. Place the light into the PRL system and press calibrate, should have three main peaks. Take away the light source and continue as before.

Beam loss: Check the IVU20c gap after a beam loss as sometimes it can be changed to higher values. Check that the front end is open.

No diffraction: Check that the pinhole is correctly centered (especially after moving/changing the cell). Check that the front end is open (especially after a beam loss). If not, open FE and start auto.

Also find the wiki link (still not completely updated) with more details.