For each start up of new user groups, the following checklist ought to be followed. The entire list could take between 10-15 minutes.

ID23-2: The microfocus capability of ID23-2 makes the end-station non-standard and a specialised instrument. Please stress this to the users when you introduce them to the line!! In order to get the most out of the beamline the users will need to take special care during data collection for radiation damage and any eventual beam and sample movements. They will need to regularly check the beam position between data sets (around every 30 minutes for < 20 micron crystals and less frequently for larger samples). See below or in the User Guide for the procedure to check this. Beam stability is strongly correlated with the temperature stability in the experimental hutch. Make sure the temperature is kept stable by minimising how many times users go in/out of the hutch (use the sample changer!) and by keeping the door shut at all times.

Change proposal number

The first thing to do is login to the new users proposal number in mxCuBE.

Check the Optics Hutch(es) and the Undulators

After a machine day (normally Tuesdays) the optics hutch may not be closed and the undulators may be fully open. Search and close the optics hutch like an experimental hutch (there may be more than one search button!).

  • ID23-2: the U20.2 should be closed to 11.55 mm. The other undulator (U35) is used by ID23-1 for MAD experiments and the gap depends on the edge being used: DO NOT MOVE IT.

Optimise the beam intensity in Experimental Hutches

For all beamlines other than ID23-2

Close the experimental hutch and optimise the beam using mxCuBE (Realign button at the top right). You should use slit sizes of 100microns on ID14-1/4 and 50 microns on ID29. The slits are automatically set to 100 microns on ID23-1. After the optimisation, users can set the slits to their required beam size. The slits should normally not be moved on ID23-1, ID23-2 and ID29.

 Be aware that repeating "Beam realign" in a short period of time will lead to beam instabilities.

 

The command "gb_mv_defaults" in Spec(opt) windows should restore default positions for slits and undulator.

Beamline Usual diode readings (depending slit settings, ring current, diode gain, etc...) with ~ 200 mA in the ring is:

dwb = 1250 cts (diode after the primary slits)
dm2b = 2500-2600 cts (diode after the secondary slits)
I0 = 400 cts (diode after slits in the slit box), with 100 % transmission and s2v = s2h = 0.2

I1 = 400 cts (diode after the shutter), with 100 % transmission and s2v = s2h = 0.2.

I0 and I1 are after the attenuators, value is function of the transmission factor and slit settings (s1 and s2). I1 can see the light from the hutch which create about 200 cts as background; to be rid off, you can switch off the light in the experimental hutch and the sample preparation lab.

Check Beam Position

Put the YAG screen in place on the phi axis with the screen perpendicular to the beam, set zoom to level 4 and focus to see the surface clearly (use the dust particles on the surface for this!). Then open the safety shutter and fast shutter using mxCuBE. Take the backstop/collimator out by clicking on the beamstop out button. Check that the X-ray beam is centred on the red cross indicating the rotation centre. This is essential as the three-click centering algorithm uses this position. If the beam is not centred in the blue box click on the Centre button in mxCuBE. This will automatically move the slits and table in order to put the beam in the box. At the end of this procedure the safety and fast shutter are closed so it may be worth reopening and checking that the beam is now centred on the blue box.

If the automatic beam centering above hasn't worked it may be necessary to manually adjust the slits and table. To bring beam to the blue box move the slit offsets to the beam, in mxCuBE select Expert mode and use Front Ver Offset and Front Hor Offset options to move the slit translations. The secondary (back) slits are set to move their offsets and gap in conjunction with the front slits. However, if you suspect that the front and back slits are misaligned with respect to each other, then in the experimental hutch spec session type scoff then close the slit gap of the front slit to 0.02, dscan t1v -.3 .3 20 1 and dscan t1h -.3 .3 20 1 and move both to the peak. Open up the front slits to 0.3 then repeat with back slit gap (i.e. dscan t2v -.3 .3 20 1 and dscan t2h -.3 .3 20 1). This should have aligned the slits to each other around the centre of the beam. Now close the front slits to 0.1 x 0.1 and the back slits to 0.12 x 0.12. Now type scon in spec and both slits should move together when you alter the front slits. Now move the slit offsets until beam is in blue box and centred on red cross. (NB moving slit1 will also move the corresponding slit2). Do a quick realign.

Slit alignment (automatic on 23-1 and 29 only at the moment)

 The slits in the slit box could be automatically realign. This alignment is optional and should be done only if one suspects the slits moved off.

The command is started by typing slitbox_align in EH1 SPEC session.

By default the slits will be set to 0.100 X 0.100 mm2 for the first slits (upstream) and 0.120 x 0.120 mm2 for the second slits downstream. Once this is done make sure the X-ray fire the center of rotation materialised by the cross on the screen after fitting the YAG screen on the goniometer head. If it is not the case, move the table (height and translation) of the same amount that you move the vertical and horizontal offsets of the slits.

Shutter Alignment (automatic on 23-1 only at the moment)

The crucial part is the alignment of the fast shutter. It would be better to do it every time users start an experiment. It is started by typing shutter_align in EH1 spec session. Do not forget to cover the detector.

It is also possible to do it manually. To do so, open the fast shutter in ProDC (you should read counts on I1 in Exes Exp). It would be perhaps safer then to have the cover on the detector even if the backstop pop in an out automatically. Go in the Scan menu in Exes Control Panel (left screen) select Equipement : Mini Diff, Procedure : dscan, Axis : shutx, Start pos. : -2, End pos. : 2, Nb points : 100, Ct. time : 0.1. Then scroll down and click on Go. This will start a dscan on on of the translation motor of the shutter. Newplot should then pop up and display the correspond scan. If not you can still start it: telnet lid232 login opid23, "newplot -s eh1", select the nov1dB counter (equivallent to I1). By fitting the curves with Maths >> Fitting >> select Back. & Slit >> Estimate >> Start fit. Position 1 Fit result will give the center of the scan. In Exes Control Panel double click on shutx motor box under Minidiff and type this new position to bring the shutter at the center. Do the same scan with shutz motor. Then the shutter will be correctly centered. close the fast shutter in ProDC.

Check Collimator/Backstop Alignment

Move the beamstop/collimator back in by clicking the beamstop in button. To see if it is properly aligned set the beam slits to the dimensions the users require for their experiment and take an image. If badly aligned and you have diffraction from collimator/backstop (typically streaks around 2.2 Angstrom resolution), look here for how to realign it.

Check position of the cryohead

There should be an alignment tool in the experimental hutch for the nozzle of the cryojet (attached by wire to the cryostream). Use the eye of a master if you cannot find this tool. Show the setting to the users and stimulate them to fine tune it if they would like to do so or have data quality problems. An experiment on data quality from different cryo to sample distances should be enough to show that this alignment is important (see interesting experiment)!

Please record the local contact data and intervention record

After the experiment, please complete your local contact data and intervention record on the SMIS website. Note that you can only do this the day after a LC and only record interventions after 8pm on weekdays and all day on weekends and public holidays.

When filling in your interventions form please bear in mind that the number of shifts actually used should ONLY be less than those allocated if the users lost time due to the Machine or beamline being down. Time not used by users for reasons like they finished early or have no samples as their dewar didn't arrive should NOT be taken into account.

mxCuBE

There is a feedback tab in the bottom part of the GUI of mxCuBE to send your comments to the developers, techs, BL scientists, etc... Please give your email address and name if you wish to get any answer...