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--- venting_pumping_object_box [2018/04/25 17:42]
pereira [Vent Object chamber]
+++ venting_pumping_object_box [2024/02/06 09:35]
noji
@@ Line 2: / Line 2: @@
 ===== Vent Object chamber =====
-Requirements: PanelMate file **S800Vac**
-  * Open **S800Vac** and go to page 01 ("Production Target Box Vacuum System sec 13")
+From the S800 Main Vacuum page, go to the Object chamber page, opening the page shown in the figure below.
-  * Verify that OBJ SCI is not biased:
-        * Check that the detectors is unbiased in the HV module sitting in dU6
+{{:wiki:screenshot_from_2024-02-06_09-20-58.png|}}
-        * Notify the system of the bias-off state by selecting the "OBJ_SCI_HV CONFIRM" box and clicking "HV CONFIRM OFF"
-  * Isolate chamber by closing gate valves **I177GV** and **I190GV**
+The vent valve should also be closed when you begin. Before you start venting, make sure of the following:
-  * [[Vacuum control|Turn off]] ion gauge **I188IG**
+  * The beamline gate valves D2341 BGV and D2303 BGV are closed
-  * Check box "PUMPDOWN STATUS BEAMLINE OBJECT BOX". It should read "Good vacuum"
+  * The IG is off
-{{:wiki:objs800vac_pumped.jpg?500|S800vac Panel Mate}}.
+  * The roughing valve RV is closed.
-  * In order to begin venting process, select box "VENT STATUS" and click "BEGIN VENTING PROCEDURE"
+  * The turbo pump gate valve TVG is closed. If the chamber will be vented for a long time, the turbo pump should be switched off .
-        * Box "VENT STATUS" should change from "VENT PROCEDURE STOPPED" to "WAITING FOR VENT TIMER", and then to "VENT VALVE OPEN"
-        * Turbo gate valve **I188GV** will be automatically closed
+The venting procedure is as follows:
-        * Vent valve **I190VV** will be automatically opened. However, the pressure in the chamber (ass seen in **I191PG** will not change because we need to open the manual venting valve
+  - Monitor the pressure RBT_BTS31:BPG_D2337:VP_RD in a data browser
-  * Go to the S800 OBJ station and slowly open the manual valve {{:wiki:ventingvalveobjbox.jpg?500|Venting valve}}. You can see the pressure rising in the Granville-Phillips 275 Mini-Convectron display.
+  - Open the vent valve
-        * When **I191PG** reads atmospheric pressure select the box "VENT STATUS" and click "STOP VENTING PROCESS"
+  - When the pressure approaches ~800 Torr, close the venting valve. Failure to do so will result in over-pressure in the chamber since it will continue to be filled with dry nitrogen
-        * The status in the box "VENT STATUS" should display "VENT PROCEDURE STOPPED" and the vent valve **I190VV** should be automatically closed
-        * Close the manual valve
+===== Pumping Object chamber =====
-        * You can now open the chamber
+From S800 Vacuum Main Page, go to Object chamber page. This will open the page in the figure below.
+  * Make sure that the IG is off.
+  * When you start, you should have RV closed, FV closed and the TGV valve, Vent valve, as well as the gate valves named D2341 BGV and D2303 BGV all closed.
+  * Open RV to start pumping down the object chamber with the roughing pump. You can make a plot of the pressure vs time at BPG at this point.
+  * Section D2337 will initially be red with vacuum status: 'Bad vacuum'. This must turn to yellow with status 'Poor vacuum'. Wait for the pressure reading at BPG to drop to below 100 mTorr before you close RV and open FV.
+  * Wait until the vacuum reading at FPG to drops to below 200 mTorr before you can safely turn on the turbo pump.
+  * After turning on the turbo pump, wait for the inner circle of the pump symbol to turn green and the pump to reach 40 000 rpm before you open the valve at TGV.
+  * When the pressure decreases to below 10-3 Torr, you should see the pressure bottom out on your BPG plot, you can turn on the IG and also plot its pressure over time. Section D2337 should turn green and the vacuum status should turn to 'Good vacuum'.

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