Approval to operate with hydrogen needs to be given. The authorization checklist is here: https://docs.google.com/document/d/13LvuOP7FBSUg4rawcie_g3sfOF0nirf4Z7H8PEaZ4EE/edit
For any testing, we use helium. Particularly for testing when in access- exceptions can be given if following a reviewed and approved procedure.
Gas system overview
This schematic covers all the IP Area gas and vacuum systems. (March 16th 2022). Red valves are installed now but we would like to modify to move the EPS valve to the location of the isolation valve (work in progress).
How to start gas jet operation
- Check first of all that the Experiment Protection System is not faulted. Go to facethome and LI20-Experimenter. Click the E-300 Oven button in the lower left corner. This takes you to a screen where you can see if the gas source is enabled or disabled. If it is disabled, then hit the EPS Reset button. If this does not fix it, it needs some expert attention which probably means talking to Christine Clarke or Doug Storey.
- Go to facethome and LI20-Experimenter. From there, select the Beckhoff Digital I/O button (the screen shows items grouped by racks- these electronics are located in rack FKG20-26). When you launch the Beckhoff system, you see the image below. The gasline valve controls are a 24 V out module. They are the module furthest to the right. See the red box. When you click this, you see options to toggle the fill and drain valves.
2. Verify Fill valve is closed. (OFF)
3. Check that the scroll pump is on and pumping. This is by penetration 20-12. There isn't a convenient electrical outlet at the moment so there is an extension cable that can be used to plug it into the outlets by 20-11 where the other pumps are. Don't plug it into the "walk up" outlets on racks as those are meant for things that don't draw much current. We've brought down LCLS by using those for pumps before.
4. Check that the manual valve to the scroll pump is open.
5. Open the drain valve (ON). This will evacuate the system of whatever is in there.
6. Pressurize the regulator to desired operating pressure Check your training! You need course 122 and potentially course 172 or "on the job experience" to change regulators. Do you know what you are doing? If not, ask Christine...
7. Close the drain valve (OFF).
8. Open the fill valve (ON).
9. Turn on the Iota controller.
10. Set it to use external and one shot.
Gas jet will now fire once it gets a trigger from the control system- see next section.
Note: can also set to internal triggers and adjust using front panel for testing.
How to change rep rate or pulse duration
This assumed Iota controller is set to external triggers and one-shot else this does nothing.
- Go to the EVR panel: Go to facethome and LI20-Experimenter. From there, select the Triggers button (the screen shows items grouped by racks- these electronics are located in rack FKG20-24).
2. Select desired rep rate for the Iota controller using the rear triggers section. The rear triggers and front triggers share the same rep rate (don't ask me why).
3. Select the desired duration (width) using the front triggers section. The rear triggers and front triggers have different duration controls (don't ask...). The example in the image above is 2 ms.
4. Set an appropriate delay- this is unknown right now. Might want to take a guess based on the laser delay time.
5. Click "Disabled" to toggle this button to "Enabled" for the front panel trigger to start pulsing.
6. Toggle this back to "Disabled" to stop pulsing.
How to shut down after gas jet operation
- Close Fill valve
- Check the scroll pump at pen 20-12 is running and there are no manual valves closed...
- Open drain valve
- Close gas bottle valve
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