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- After waiting ~30 mins, press the "Full Open" button on "MagRetBypass_Main.vi" in CCP, to open the MagRetBypass valve fully, and wait until you can see it is fully open on CCP panel.
You will start seeing the magnet pressure start decreasing. - When the magnet pressure reaches 3psi, Open VJVT and close VPC.
- Monitor the FMR and make sure the total flow is below 500 slm. If it is above 500slm then wait until it is below 500 slm. Also, ensure the PC 1 is also below 1.5 psi.
- Monitor the behavior of the magnet pressure, and once the magnet pressure is below 2psi, then Switch the liquefier that you are filling, to "Manual + Idle" mode, and open SV501 solenoid valve, and after that set FC501 to 45slm.
Note: Monitor the FMR and make sure the total flow is below 500slm. If it is above 500slm then use 40slm on FC501. - Monitor the pressure difference (between magnet and delivery Dewar) using the "LHe Transfer page", and ensure it keeps increasing towards 3.0 psi.
Ensure the FMR value doesn't exceed 500slm (~480slm would be ideal) and if it is increasing above 500slm, then reduce the "FC501" by a couple of 'slm' and continue to monitor. - Monitor the parameters using https://e906-gat1.fnal.gov/data-summary/e1039/target-par-preset/transfer.php
- You may need to reduce (increase) it if the pressure difference is increasing-faster (reducing) while monitoring the FMR; but 45 slm seems the nominal value based on the past fills.
- Keep monitoring the fill parameters: Magnet level, Delivery Dewar level, Pressure difference, FMR
- Maintain the pressure differential above 3 psi, by adjusting FC501A/B if necessary (after setting FC501A/B to 40slm is usually smooth until the end of the fill, but pay attention in-case you have to change it)
- Monitor everything, until the magnet level reaches 50%, and then observe a level-spike that confirms that you have filled the magnet up to the top level (145 L).
In case you don't have enough liquid in the delivery dewar, you can stop before seeing the level-spike. - Open VPC, Close VJVA/B, Close VJVT.
- This is the end time of the transfer. Record the time, the magnet level, and the Liq level.
- Enable the auto control of the MagRetBypass valve. Change the set point to 0.9 psi.
- Change the Liq mode to "Auto+ Liquefy" mode:
- Change the Dewar Set pressure to 6.5 psi.
- Set the outlet flow is 40 SLM. Note: you will need to pay attention to this Liquefier for the next ~1 hr until you change this to 2 slm step-by-step while monitoring the Dewar pressure (follow Steps #17, #18).
If the Dewar pressure is keep increasing beyond the Set pressure (6.5 psi), then you will need to increase this outlet flow to 60slm. When you change this, always confirm on the Liquefier screen's FCA/B whether it's flowing what you set to. If not, you will have to quickly press "Idle" button and then press "Liquefy" button immediately after. - The Liquefier Compressors' coldhead heaters should be OFF, but it's better to confirm that on the "Helium Compressors" screen.
If they are ON, please turn them off one-by-one (double tap/click on each button for heaters). - If you change the mode of the other liquefier in step #4, then change it back to Liquefy mode.
- Wait until the Liquefier's Dewar pressure (PT503) gets slightly below 6.5 psi, and then check the actual inlet flow (FC501 A/B I) to the liquefier is above 40 SLM (FC501 A/B Q will be 60 slm).
This indicates that you can change the Outlet Flow Set point to a lower value like 30slm (follow the next steps over the next ~40 mins).
Note: Ensure the Dewar pressure doesn't go above 9 psig. If it is rising, you should change the Outlet Flow Set point to 60slm and wait until the Dewar pressure is between 6-7 psi. - Repeat step #17 with outlet flows = 20, 10, 5slm, and and then to 2 SLM when the cold-head temperatures are below 5.5 K.
- Confirm that the Liq pressure stays around the set point (6.5 slm).
- Calculate the transfer efficiency using initial and final levels in the magnet and the Liquefier Dewar.
- Post the filled Magnet_LHe_Fill_Checklist.docx file on uva-elog including the date of the fill as part of the file name (for example: Magnet_LHe_Fill_Checklist_03-29-2024.docx or .pdf file)
If you don't have access to the uva-elog, then please send this file to the Target Expert on shift.
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