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--- venting_pumping_intermediate_image_box [2017/06/14 10:59]
pereira [Pumping Intermediate-image chamber]
+++ venting_pumping_intermediate_image_box [2024/01/12 09:37] (current)
noji [Filling and Running Detectors]
@@ Line 1: / Line 1: @@
-====== Venting/pumping Intermediate Image box and filling PPACs with gas ======
+====== Venting/pumping II chamber & emptying/filling gaseous detectors ======
-The procedures to vent/pump the S800 Intermediate Image box, and/or filling the PPAC detectors with gas must be done carefully to ensure that the PPACs are not damaged. For instance, before venting the chamber, we have to make sure that the PPACs are empty and equalized with respect to the vacuum in the chamber. In order to avoid errors, an automated gas handling system (II-GHS) was designed to perform these tasks safely. The system is schematically illustrated in the figure below. It shows the status of the valves (red: closed, white: open) when the intermediate image chamber is under vacuum and the PPACs are filled with gas:
+  * [[#General information]]
+  * [[#Emptying Detectors]]
+  * [[#Venting the Chamber]]
+  * [[#Evacuating the Chamber]]
+  * [[#Filling and Running Detectors]]
+  * [[#Troubleshooting]]
+===== General information =====
+The procedures to vent/pump the S800 Intermediate Image box, and/or filling the PPAC detectors with gas must be done carefully to ensure that the PPACs are not damaged. For instance, before venting the chamber, we have to make sure that the PPACs are empty and equalized with respect to the vacuum in the chamber. In order to avoid errors, an automated gas handling system (II-GHS) was designed to perform these tasks safely. The II-GHS equipment (valves, flow-meter, pipes, isobutane gas bottle. etc.) are located on the west balcony of the top level in the S3 vault (see figure below):
-{{:wiki:ghsiippacs.png?1000|Gas Handling System of S800 Intermediate Image}}
+{{:wiki:IIGHShardware.jpeg|Gas Handling System of S800 Intermediate Image}}
-The II-GHS equipment (valves, flow-meter, pipes, isobutane gas bottle. etc.) are located on the west balcony of the top level in the S3 vault (see figure below):
+The GHS is operated remotely through CS studio. Its page can be found on the EXP network through FRIB EXP Main → S800 → GHS Pages (Secondary Pages) → Intermediate Image PPAC and is shown below.
-{{:wiki:IIGHShardware.jpg?600|Gas Handling System of S800 Intermediate Image}}
+{{:wiki:ii-ppac-ghs-css.png|}}
+The layout of the II-GHS is shown below.
+{{:wiki:ii-ppac-ghs-layout.png|}}
+The operational states of the II-GHS are shown in the diagram below.
+{{:wiki:ii-ppac-ghs-operationalstates.png|}}
+===== 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.
+  - When “PPAC Pressure” reads < 0.1 Torr, turn off IG and click **MAN** and then **AUTO**. This will open valve #6 to release the remaining gas into the diagnostics box.
+  - Monitor D2340 pumping station and ensure the TMP stays on and TGV remains open. If not, contact the Vacuum Operation group.
+  - Valves #1-5 should be closed and valve #6 should remain open. From this state click **VENT** and then **PUMP** to enter pump mode and leave the system in this state until it is ready to be filled.
+===== Venting the Chamber =====
+From the S800 Main Vacuum page, go to the Intermediate Image - RBT_BTS32 D2430 Pumping Station page, and ensure
+  * that the PPACs have been unbiased,
+  * that this pumping station has been isolated by having the gate valves **D2426 BGV** and **D2436 BGV** closed, and that the IG has been turned off, and
+  * that the turbo pump gate valve **TVG** is closed.
-===== Vent Intermediate-image chamber =====
+The TMP can be turned off at this time.
-Requirements: PanelMate files **S3_Gas_Handling** and **S800Vac**
-  * Verify that PPACs are in automatic mode with gas removed (**S3_Gas_Handling**)
+To vent the chamber:
-        *  The "GH System Status box should read "Auto Mode Gas Removed"
+  - Let the Control Room and the Vacuum Operation Group be aware as EXP alarms may occur,
-        * If gas is removed but the system is not in the automatic mode, consult the Beam Physicists or Device Physicist. NOTE: the only valves that should be open in **S3_Gas_Handling** are the "Det Bypass" and "Chmbr Bypass
+  - put the GHS in vent mode by clicking **VENT** (valves #5 and #6 are open),
-  * Verify that PPACs are not biased:
+  - monitor **RBT_BTS32:BPG_D2430:VP_RD** and **S800_GHS:PI_D2431:V_RD_AB** in a data browser,
-        * Check that the detectors are unbiased by opening the [[HV bias|HV GUI]]
+  - ensure that **RV**, the valve to the roughing pump, is closed, and
-        * Notify the system of the bias-off state by selecting the "I214BON_CONFIRM" box in **S3_Gas_Handling** and clicking "PP BIAS OFF CONFIRMED"
+  - open **Vent** valve to start venting.
-  * Isolate chamber by closing gate valves **I212GV** and **I215GV**
-  * [[Vacuum control|Turn off]] ion gauge **I213IG**
-  * Open **S800Vac** and go to page 03 ("Intermediate image box vacuum system sec 15")
-  * Check box "PUMPDOWN STATUS INTERMEDIATE IMAGE BOX". It should read "Good vacuum"
-{{:wiki:iis800vac_pumped.jpg?500|S800vac Panel Mate}}.
-  * In order to begin venting process, select that box and click "BEGIN VENTING PROCEDURE"
-        * Box "VENT STATUS" should change from "VENT PROCEDURE STOPPED" to "WAITING FOR VENT TIMER".
-        * Turbo gate valve **I214GV** will be automatically closed and pressure in chamber will start rising (as seen in **I215PG**) {{:wiki:iis800vac_startventing.jpg?500|S800vac Panel Mate: start venting}}.
-        * When **I215PG** reads atmospheric pressure, select the box "VENT STATUS" and click "STOP VENTING PROCESS". {{:wiki:iis800vac_stopventing.jpg?500|S800vac Panel Mate: stop venting}}.
-        * The status in the box "VENT STATUS" should change from "WAITING FOR VENT TIMER" to "VENT PROCEDURE STOPPED"
+The PPAC pressure S800_GHS:PI_D2431:V_RD_AB should closely follow the chamber pressure
-        * You can now open the chamber
+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 =====
+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 |}}
-===== Pumping Intermediate-image chamber =====
+To evacuate the chamber:
-Requirements: PanelMate files **S3_Gas_Handling** and **S800Vac**
+  - double-check and make sure that the manual valve is closed,
-  * Verify that Chamber is closed and pressure-relief valve (north side of the chamber) is properly closed (NOTE: sometimes, due to overpressure from dry N2 during the venting procedure, the O-ring in pressure-relief valve flange is moved out of place)
+  - put the GHS in pump mode by clicking **PUMP** (valves #3, #5, #6 are open),
-  * Verify that PPACs are not biased by opening the [[HV bias|HV GUI]]
+  - close **FV** below the TMP, and
-  * IMPORTANT: Close manual roughing pump valve located near the intermediate-image chamber {{:wiki:manualvalverough.jpg?350|Manual valve rough pump}}.
+  - 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**.
-  * Insert PPACs/turn on light (Diagnostic Drives PanelMate) and verify condition through sight window on south side of the chamber (be careful no to bump the bullet camera).
+  - 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.
-  * Open **S800Vac** and go to page 03 ("Intermediate image box vacuum system sec 15")
+  - 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.
-  * Check "PUMPDOWN STATUS INTERMEDIATE IMAGE BOX"; it should read "PUMPDOWN STOPPED". Select that box and click on "START PUMPDOWN". The chamber will not be pumped yet because the manual roughing pump valve is closed.
+  - Turn on TMP, and wait until it reaches the normal rotation (~40,000 rpm).
-  * Slowly crack manual roughing valve
+  - Open **TGV**.
-        * Start slow (< 1 Torr/sec). Chamber pressure is displayed in **I215PG** in **S800Vac** PanelMate. There is also a local display of the mechanical pump pressure on a Granville-Phillips 275 Mini-Convectron, which is helpful to control rate of pumping.
+  - Be sure to go back to S3 and close the manual valve.
-        * Verify PPACs changing shape through sighting window.
+===== Filling and Running Detectors =====
-        * Pump to about 100 Torr before fully opening the roughing valve.
+  - 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).
-  * Once roughing valve is fully open, retract PPACs and turn lights off.
+  - If in Pump Mode, click **RUN** to enter Run Mode.
-  * When the pressure in **I215PG** is below 200 mTorr, the Turbo Pump will start automatically through the following sequence:
+  - 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.
-        * **I214RV** will be closed
+  - Step up “PPAC Setpoint” by 1 Torr from 0 to 6 Torr. Allow the “PPAC Pressure” to stabilize for 15 seconds at each step. This should be a quick process but **DO NOT** simply set the “PPAC Setpoint” to 6 Torr as the gas flow could overwhelm the system.
-        * **I214FV** will be opened
+  - PPAC pressure should stabilize after ~1 min. HV may now be turned on to operate the PPACs.
-        * **I214GV** will be opened
-  * When the pressure ready by **I215PG** is few mTorr, you can turn on the ion gauge **I213IG**. Good vacuum will take ~1-2 hours.
-  * NOTE: it sometimes happens that the foreline pressure rises above the trip point for the Turbo Pump (e.g. if the pumpdown timer expires before pressure is below 300 mTorr). In this case the foreline valve needs to be bypassed open (in PanelMate) and the TP needs to be restarted.
-  * At the end of the procedure, close the manual roughing pump valve
+===== Troubleshooting =====
+  - If any issues are encountered during filling, running, or emptying, contact the Vacuum Operation group for assistance.

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