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--- venting_pumping_intermediate_image_box [2018/08/14 10:29]
pereira [Pumping Intermediate-image chamber]
+++ venting_pumping_intermediate_image_box [2024/01/11 10:33]
noji [Venting the Chamber]
@@ 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 (NOTE: This figure was taken from the A1900 GHS included in Barney. A similar GUI for the S800 II PPACs is not yet available):
+  * [[#General information]]
+  * [[#Emptying Detectors]]
+  * [[#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 =====
+  - 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 =====
+To vent the chamber:
-Requirements: PanelMate files **S3_Gas_Handling** and **S800Vac**
+  - Put the GHS in vent mode by clicking **VENT**,
+  - 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
+  - open **Vent**.
-  * Verify that PPACs are in automatic mode with gas removed (**S3_Gas_Handling**)
+The PPAC pressure S800_GHS:PI_D2431:V_RD_AB should closely follow the chamber pressure
-        *  The "GH System Status box should read "Auto Mode Gas Removed"
+RBT_BTS32:BPG_D2430:VP_RD
-        * 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
+===== Evacuating the Chamber =====
-  * Verify that PPACs are not biased:
-        * Check that the detectors are unbiased by opening the [[HV bias|HV GUI]]
-        * Notify the system of the bias-off state by selecting the "I214BON_CONFIRM" box in **S3_Gas_Handling** and clicking "PP BIAS OFF CONFIRMED"
-  * 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 box "VENT STATUS" 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"
+{{:wiki:iimanualvalve.jpeg|}}
-        * You can now open the chamber
+===== Filling and Running Detectors =====
+  - If in Vent Mode, click **PUMP** then click **RUN** to enter Run Mode.
+  - If in Pump Mode, click **RUN** to enter Run Mode.
-===== Pumping Intermediate-image chamber =====
+  - 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.
-Requirements: PanelMate files **S3_Gas_Handling** and **S800Vac**
+  - 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.
-  * 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)
+  - PPAC pressure should stabilize after ~1 min. HV may now be turned on to operate the PPACs.
-  * Verify that PPACs are not biased by opening the [[HV bias|HV GUI]]
-  * IMPORTANT: Verify that manual roughing pump valve located near the intermediate-image chamber is closed{{:wiki:manualvalverough.jpg?350|Manual valve rough pump}}.
-  * 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).
-  * Open **S800Vac** and go to page 03 ("Intermediate image box vacuum system sec 15")
-  * 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.
-  * Slowly crack manual roughing valve
-        * 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.
-        * Verify PPACs changing shape through sighting window.
-        * Pump to about 100 Torr before fully opening the roughing valve.
-  * Once roughing valve is fully open, retract PPACs and turn lights off.
-  * When the pressure in **I215PG** is below 200 mTorr, the Turbo Pump will start automatically through the following sequence:
-        * **I214RV** will be closed
-        * **I214FV** will be opened
-        * **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, or there is too much back-up pressure from the chamber when the foreline valve opens). In this situation, you will see that: (1) the turbo pump will stop, (2) the turbo gate valve **I214GV** will be closed, (3) the foreline valve **I214FV** will be closed and the corresponding PanelMate box will turn red and display an error message "Foreline pressure > 2 Torr", and (4) the foreline pressure will be few Torr. In a situation like this, foreline valve needs to be bypassed open (in PanelMate) and the TP needs to be restarted. When the TP is at speed (40000 RPM) the **I214GV** will open automatically (Note: sometimes it is necessary to repeat this operation a couple of times). When the TP is running fine and the system is stable (pressure in **I326PG** ~ mTorr), you can remove the bypass of the foreline valve
-  * 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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