Differences

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--- venting_pumping_intermediate_image_box [2024/01/11 10:37]
noji [Venting the Chamber]
+++ venting_pumping_intermediate_image_box [2024/01/12 09:37] (current)
noji [Filling and Running Detectors]
@@ Line 2: / Line 2: @@
   * [[#General information]]
   * [[#Emptying Detectors]]
+  * [[#Venting the Chamber]]
+  * [[#Evacuating the Chamber]]
   * [[#Filling and Running Detectors]]
   * [[#Troubleshooting]]
@@ Line 22: / Line 24: @@
 ===== Emptying Detectors =====
+  - Double check that the detectors have been unbiased.
   - Set “PPAC Setpoint” to 0 Torr.
   - Click **EMPTY** on the “GHS_II-PPAC_Main” page to open valves #3 and #4 which will allow for pumping out the gas quickly.
@@ Line 37: / Line 40: @@
 To vent the chamber:
-  - Put the GHS in vent mode by clicking **VENT** (valves #5 and #6 are open),
+  - Let the Control Room and the Vacuum Operation Group be aware as EXP alarms may occur,
+  - put the GHS in vent mode by clicking **VENT** (valves #5 and #6 are open),
   - monitor **RBT_BTS32:BPG_D2430:VP_RD** and **S800_GHS:PI_D2431:V_RD_AB** in a data browser,
-  - close **RV**, the valve to the roughing pump, and
+  - ensure that **RV**, the valve to the roughing pump, is closed, and
-  - open **Vent**.
+  - open **Vent** valve to start venting.
 The PPAC pressure S800_GHS:PI_D2431:V_RD_AB should closely follow the chamber pressure
-RBT_BTS32:BPG_D2430:VP_RD
+RBT_BTS32:BPG_D2430:VP_RD up to about 10 Torr, which is the upper limit of the range of the gauge for S800_GHS:PI_D2431:V_RD_AB.
 ===== Evacuating the Chamber =====
-{{:wiki:iimanualvalve.jpeg|}}
+Ensure
+  * that the chamber is closed
+  * that the pressure-relief mechanism (on the north side of the chamber, see picture below) is sealing (if not, adjust the flange back in place)
+{{ :wiki:iipressurereliefmechanism.jpeg?600 |}}
+  * that the manual valve (see picture below) is closed.
+{{ :wiki:iimanualvalve.jpeg |}}
+To evacuate the chamber:
+  - double-check and make sure that the manual valve is closed,
+  - put the GHS in pump mode by clicking **PUMP** (valves #3, #5, #6 are open),
+  - close **FV** below the TMP, and
+  - open **RV**.
+  - A message window, which reads, "Roughing Valve should only be opened if Manual Valve is CLOSED. Confirm Manual Valve is CLOSED before proceeding." of the manual valve is confirmed to be closed, acknowledge the message and click "Yes". This will open **RV**.
+  - now open the manual valve slowly while watching the local display of the Pirani gauge. Open slowly such that the pressure reading (in Torr) goes down by about 1 unit per second initially. The valve needs to open more as the pressure goes further down.
+  - On the CSS window, after D2430 turns to yellow indicating that the section is in "POOR VACUUM", wait until the BPG reading to go below 100 mTorr before closing RV and opening FV.
+  - Turn on TMP, and wait until it reaches the normal rotation (~40,000 rpm).
+  - Open **TGV**.
+  - Be sure to go back to S3 and close the manual valve.
 ===== Filling and Running Detectors =====
-  - If in Vent Mode, click **PUMP** then click **RUN** to enter Run Mode.
+  - If in Vent Mode, click **PUMP** then click **RUN** to enter Run Mode. The valves #1 opens and #3 remains open (#5 and #6 will be closed, and the GHS lines will be isolated from the chamber).
   - If in Pump Mode, click **RUN** to enter Run Mode.
   - Plot and monitor IG_D2430:VP_RD while filling. Ion gauge reading will increase but should remain <1E-5 Torr when PPACs are running at full pressure.

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