Checking the bottle pressure

To check the bottle pressure (in psi), the inside gauge (markings are in red) use the LArIAT webcam link: An approximate value should be given when viewing the webcam (the gauge you need to report is marked by Perfect Pie, the little pony. If the pony is missing - this is the second gauge, counting from the left).


... and that's all you need to know to check the bottle pressure.

The minimum gas pressure is 18 psi to run for next 24 hours, if it goes below that value please report the Run Coordinator .

Wire Chamber System: Turning it all on or off

Step-by-step instructions for turning on and off the gas and power for the wire chambers. Some of these steps may not be necessary (for example, if there is a shifter coming in immediately after you, or if some power supplies are already on.)

Turning chambers ON

Turning gas ON at Flammable Gas Rack "D"
  1. Open the gas cylinder in the cage (but don't move the gauge). Be sure you are opening a cylinder that isn't marked "Empty", and that it is connected to the switchboard and bubblers.
  2. Turn the black knob at the top of the yellow and red panels to the open position.
  3. Turn the switch at the bottom of each panel from OFF to flammable normal operation position. The arrow side of the switch has to be directed to the right. INERT PURGE side does not work.
  4. Wait a few minutes and check if you see bubbles appearing in the Return lines.

Wire Chambers HV
  1. Make sure gas has been flowing for 30 minutes (you should see bubbles on the Return lines).
  2. On the Orange Dual MWPC labeled Power Supplies at the top of MCCR04 rack (MC7-MWPC1, MC7-MWPC1, MC7-MWPC1, MC7-MWPC1):
    1. First check that the four black knobs are turned all the way counter-clockwise to 0.
    2. Turn the four switches ON.
    3. If there is no red LED, you may need to use the Trip/Reset switches. Leave them in "Auto" once the red LED lights up.
    4. Turn the black knobs slowly to 500V (0.5V on a multimeter) while monitoring the correct current using the Meter Select switch just under the current gauge. The current will fluctuate slightly while ramping up -- if it jumps above 0.2 mA and stays there for any length of time, STOP and let someone know.
    5. Repeat ramping up slowly in steps of 500V until reaching the correct operating voltages (should be posted).

Turning chambers and electronics OFF

Wire chambers HV OFF
  1. Turn the four black knobs all the way counter-clockwise to 0.
  2. Turn the supplies OFF.
Close gas OFF
  1. Turn switches on yellow and red panel from flammable to OFF position.
  2. Turn black knob at top of each panel to closed position.
  3. Close the gas cylinder in the cage (don't move the gauge).