Page History

Updating for all DPS pumps being installed, but no apertures except for thou holey upstream window.

Gas jet max rep rate (updated 7/12/2022):

There are various ways to define the max gas jet, but it is some combinations of keeping the PB pressure low, and keeping the pressures low at either end of the DPS. If the pressure in US4 stays in the low 1e-10 scale, then the pressure rise on 3073 (TCAV) is less than a 1e-9 Torr.

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1. Follow the gas jet how to page to get the gas jets ready: How to use gas jet
   
   1. Use the plot above to chose the max backing pressure and rep rate
2. Ensure 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.
3. Start a strip tool and load the file: DPS_Gasjet_Pressures.stp
4. Park the beam on TD11
5. Insert VVPG:LI20:3160 and VVPG:LI20:VV3250
6. Increase the setpoints on the VV:3250 interlocks on gauges 3291:DS2 and 3249
   
   1. Select each gauge, then select the "More..." button beside Status in the "Interlock Output Pressure Status" and increase to 1e-3 on each gauge.
   2. Remember to set this back at the end of the shift!
   Set interlock bypasses on VGXX:LI20:3259:DS1. These gauges will read high pressure while gas jets are firing.
7. Fire the gas jet once and watch the strip chart. If the 3130 3108 and 3291 pressures say below ~1e-5 Torr
8. Fire the gas jet for a minute or so and watch the strip chart.
9. If all looks good, then stop the gas jets and open the beamline valves
10. Fire the gas jets and watch CC3073 pressure. If there is no change, then you are good to fire at will.

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1. If the lone cold cathode gauges shut themselves off, then turn them back on. If pressure reads above 1e-3 Torr then turn it back off.
2. If a CC gauges on 3171 or 3259 are cycling on and off, then force them to stay off (or on if it is in a safe pressure zone)
   1. Change the control mode to Off, then turn CC HV off.
3. Watch the PB and oven turbo temperatures
4. Watch CC3073 to see if it ever changes.
5. Watch if the DPS foreline valves trip in and the turbos shut off. If this happens DO NOT TRY TO FIX unless you are Doug, or Christine, or Ryan.

How to stop everything at the end:

1. Stop firing the jets and follow How to use gas jet to shutdown and depressurize the gas jet system.
2. Remove the gauge bypasses on VGXX:LI20:3171:US1 and VGXX:LI20:3259:DS1any changes to interlocks that you made.
3. Reset any cold cathode gauge "control modes" that were changed back to auto.
4. Call ACR and tell them everything has been reset.

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