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1. Verify vacuum conditions in the IP of approximately 1e-6 Torr (or lower) on the 3259 guage.
2. Verify both US-DPS and DS-DPS pumps are running and operating as normal.  Also check VPIO:LI20:3164 to ensure the ion pump is on.
   1. This is how the DPS looks under nominal operation:
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3. Start a strip tool and load the file: DPS_Gasjet_Pressures.stp
   1. Find the VGCM:LI20:M3203:PMONRAW pressure - this is the 10 Torr capacitance manometer gauge that will provide the IP pressure.
4. Open the "E-300 oven" panel from LI20 Experiment page. See below for details. The figure shows the important items:
   1. You will use the "Fill Gas #1" ON and OFF buttons to start and stop gas flowing to the IP
   2. "Gas 1 & 2 Supply" tells you if the the EPS system is allowing the gas to flow or not. "On" = good" will allow you to open the fill valve.  "Off" means there is a problem.
   3. The "EPS RESET" button will reset the EPS faults (if the faults have been cleared) and allow you to flow gas again.
      
   4. The 10 Torr gauge reading gives the IP pressure
      
      
      
5. Open the "Gas jet control panel" from the LI20 Experiment page
   1. Press MAX beside "Set foreline pump speeds"
   2. Click "Gas Type..." and at the bottom of the page, select the gas species that you will use.
      
      1. Note - there is no hydrogen calibration, so use Helium instead.
         
6. Set up the mass flow controller, but leave the flow rate at 0 for now: How to use MKS mass flow controller (DPS
   
   From the Gallery:
7. Verify the oven fill line is connected to the gas bottle of the desired gas type:
   1. Gas bottles and flow regulator location:
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8. Open the gas bottle and set the regulator to 10 psig. Open the line valve after the bottle.
9. Read the gas bottle pressure and ensure that there is enough gas to last for the intended fill.
   1. Previous measured rate of He usage at 5 Torr IP pressure = 165 psi/day (one full 2500 psi bottle drained in ~15 days)
10. If using hydrogen, you need to start a nitrogen purge to increase the pumping efficiency:
    1. Open the nitrogen 6 pack main valve and ensure that there is ~10 PSIG pressure on the regulator. Check that the other in-line valves are open
    2. From Epics - open the "Gas Jet Control" panel from LI20 Experiment page
    3. Change the value of "US1 purge gas" and "DS1 purge gas" to ON
       1. You should verify that the purge gas is flowing by opening:  DPS Full Schematic → US1 and DS1 roughing pumps → More..., and read the "N2 Flow" PV. It should be reading ~4 Pa.m³/s
11. Verify gas bottle on fill line #2 is closed and that the fill valve for this line is closed. Ensure that the IOTA controller in FKG20-24 is turned OFF.If using hydrogen, you need to start a nitrogen purge to increase the pumping efficiency
    
    From Epics again:
12. Inform ACR that you are going to start the gas fill in the S20 IP
13. Open the fill valve #1
14. From the MFC controller - start flow at a low level (50) to purge gas through the fill line for several minutes.
15. Close the fill valve to stop the flow and evacuate the IP again.
16. If operating the Li oven, follow the E300 procedure to prepare the Li oven for a static fill.

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1. If using the Li oven, follow appropriate procedures to shut down and secure the oven
2. When ready to drain the He gas - close the fill valve. The IP pressure will drop at an initial rate of ~1 Torr/min.
3. Set the flow rate on the MFC to zero.
4. Open valve FV-PB on the foreline of the Picnic Basket to aid in the pump down
5. Start the PB turbo when the IP pressure is below 1 Torr.
6. Close the valve on the gas bottle.
7. Open the DS Beryllium window valve VV3208 after the IP pressure is <<1 Torr.
8. Set the gas type back to Nitogen (From the gas jet panel)
9. Set the purge gas to OFF (From the gas jet panel), and close the valve on the N2 6-pack

Recovering from faults:

If a single stage in the DPS trips off, the IP pressure should not be effected significantly so the fill valve, oven valves, and oven heaters should remain open or on.  The decision to halt operation of the oven should be made depending on the nature of the fault. The problem should be fixed as soon as possible to regain redundancy in the DPS system.

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