Operating the beamline


General

The user-controlled electropneumatic valves of the beamline (labelled by numbers 1-10 in the screenshot adapted from the Beamline Control System (BCS) webpage above). Before using the beam for data acquisition the beamline must be open for at least 30 minutes in order to reach thermal stability of its optical elements (warm-up), mainly of the prefocusing mirror, which is being hit by the most intense light (40 W incident, of which 90% absorbed). The valves can be operated using
  • the Beamline software, or
  • the BCS webpage (single click on the valve) on the MSB-MASTER or MSB-STATION computers, or
  • the BCS section of the Kleopatra software (double click on the valve) from the MSB-MASTER computer (or its VNC copy on the MSB-STATION computer).
The simplest one is the first option where you can use just 3 buttons Close (to close all valves), Standby (to keep open valves 1-9 to keep the beamline warming up) and Acquire (to let the beam enter the analysis chamber for data acquisition). The correct order is automatically respected.

The other two options open a webpage where the desired command (1) open or (0) close can be selected and Submitted. It will open another webpage with the result of the operation. The status of each valve is indicated by color (green - closed, red - open). The displayed status is refreshed only every 10-40 s so the change might not be immediately visible..

Opening the beamline using the Beamline software

  1. When the Beam status is OK open valves 1-9 using the Standby button. When done you should see Mesh current > 0.
  2. Leave the beamline warm up for at least 30 minutes.
  3. Proceed with setting the beam position if needed.
  4. For data acquisition open valve 10 using the Acquire button.
  5. Proceed with sample alignment (full or fast check as needed).
  6. Start your measurements.

Closing the beamline

  1. Immediately after data acquisition and before any operations in the analysis chamber that may cause pressure increase close valve 10 using the Standby button so the beamline stays warming up..
  2. At the end of the day close all valves using the Close button.

 

Opening the beamline using the web-based method

  1. Check that the beam is available for users (beam energy ≥2 GeV, accumulated current ≥100 mA, machine status User Dedicated, "luce utenti" announced).
  2. Check that the pressures along the beamline are in the 10-9 mbar order or below (except for the shutter chamber being 10-7 mbar due to incorrect measurement).
  3. Open the electropneumatic valves 9 to 1 (in this order). After this you should observe some mesh current in the Mesh Monitor software.
  4. Wait at least 30 min (until the mesh current stabilizes).
  5. Proceed with setting the beam position if needed.
  6. Open the electropneumatic valve 10.
  7. Proceed with sample alignment (full or fast check as needed).
  8. Start your measurements.

Closing the beamline

  1. Close the electropneumatic valve 10 (if not done before).
  2. Close the electropneumatic valves 1 to 9 (in this order).

Notes

Valves a, b and c cannot be controlled by the user.
  • Valves a and b are closed by the machine operators before the injection (e.g. in the case of a beam dump) and open after it. If the operators forget to open these valves after the injection call the Control Room (telephone number is on the machine status webpage) and ask kindly to open the machine shutter of the beamline 6.1 Materials Science.
  • Valve c is a security fast valve closed automatically if vacuum is broken.
Valves 1 and 3 (shutter and stopper) are also closed by the machine operators before the injection in the case of a beam dump, locked during the injection (symbol  in Kleopatra) but not open automatically after. So when the beam is again available, open them using the Standby button in Beamline software or manually in the correct order. (valve 3 and then valve 1). If they keep being locked although the injection is finished (machine status User Dedicated, "luce utenti" announced), call the Control Room (telephone number is on the machine status webpage) and ask the operator to unlock the beamline shutters and stoppers.

Valve 1 also automatically closes when there is not enough flow of the cooling water of the beamline prefocusing mirror, entrance slit and/or monochromator. Check Water status being OK in the Beamline software or on the web and increase it if needed.

The correct opening/closing order of valves 1-7 is important. The scope is to avoid hitting any of the valves 2-7 by the photon beam when they are closed. Therefore the valve 1 should be open as the last one and closed as the first one, as it is the only one that can support the heat load of the beam (it is water-cooled). Although there are some interlocks that should avoid user errors please respect the correct order.

Open the valve 10 to the analysis chamber only for the period of photoemission measurements and close it immediately after. Double-check that it is closed especially when performing operations leading to pressure increase in the analysis chamber, typically sample transfer, ion sputtering or gas exposure, or during photoemission with X-ray source (to avoid mixing two different excitations). Moreover, some sensitive samples might be damaged by long exposures to the photon beam so there is no reason to illuminate them when not needed.

If the BCS webpage does not open at all and the BCS section of Kleopatra is of grey color and does not react on double-clicks on valves wait for several minutes. If the problem persists follow Troubleshooting - BCS communication problem.

Last Updated on Thursday, 19 May 2022 13:09