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--- venting_pumping_intermediate_image_box [2017/06/12 12:36]
pereira [Venting/pumping Intermediate Image box]
+++ venting_pumping_intermediate_image_box [2017/06/12 14:52]
pereira [Vent focal-plane chamber]
@@ Line 1: / Line 1: @@
 ===== Venting/pumping Intermediate Image box and filling PPACs with gas =====
-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 was designed to perform these tasks safety. The system is schematically illustrated in the figure below:
+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 safety. 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:
 {{:wiki:ghsiippacs.png?1000|Gas Handling System of S800 Intermediate Image}}
+The II-GHS equipment (valves, flow-meter, pipes, etc.) are located on the west balcony of the top level in the S3 vault (see figure below):
+{{:wiki:IIGHShardware.jpg?600|Gas Handling System of S800 Intermediate Image}}
 ==== Vent focal-plane chamber ====
-  * Open the [[hv_bias|HV Remote Control]] GUI and ensure that the focal-plane detectors are unbiased
+Requirements: PanelMate files **S3_Gas_Handling** and **S800Vac**
-  * Open the [[gas_handling_system#labview_control_program|Labview gas handling system]] and verify that there is no gas in the CRDCs and IC. Open valves **4** (IC supply), **5** (IC bypass), **6** (IC focal-plane bypass), **20** (CRDC supply), **21** (CRDC bypass), and **22** (CRDC focal-plane bypass). The rest of the valves should be closed
-  * Ensure that the manual venting valve located on the south side of the chamber is closed (see figures below)  {{:wiki:fp-venting-valve-Daniel.jpg?350|FP chamber manual venting valve}} {{:wiki:fp-venting-valve.jpg?350|FP chamber manual venting valve}}
+  * Verify that PPACs are in automatic mode with gas removed (**S3_Gas_Handling**)
-  * Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]])
+        *  The "GH System Status box should read "Auto Mode Gas Removed"
-  * Open PanelMate and select **S800vac** file in directory \\exp\files\control\ncsdata\General\Qt\Templates. Go to page 07, click on the **VENT STATUS** window and begin the venting procedure. The **VENT VALVE I260VV** window will turn red and display "OPEN". The pressure should remain constant because the manual venting valve is still closed
+        * 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
-  * Gently open the manual venting valve until the pressure displayed in the Pirani Gauge (see figure below) increases by ~1 torr every 15 seconds (see figures below)
+  * Verify that PPACs are not biased:
-{{:wiki:fp-pirani.jpg?350|FP chamber manual venting valve}}
+        * Check that the detectors are unbiased by opening the [[HV bias|HV GUI]]
-  * Wait until the chamber is vented (few hours). The **I261PG** Pirani Gauge should read slightly above atmospheric pressure (due to the dry N2 flow pumped to the chamber). The window **VENT STATUS** in PanelMate should display "VENT VALVE OPEN". The window **PUMPDOWN STATUS** should display "PUMPDOWN STOPPED"
+        * 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?350|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?350|S800vac Panel Mate: start venting}}.
+        * When pressure in **I215PG** reaches atmospheric pressure, stop the venting process by selecting the box "VENT STATUS" and clicking "STOP VENTING PROCESS"
+{{:wiki:iis800vac_stopventing.jpg?350|S800vac Panel Mate: stop venting}}.
+        * The status in the box "VENT STATUS" should change from "WAITING FOR VENT TIMER" to "VENT PROCEDURE STOPPED"
+        * You can now open the chamber

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