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--- venting_pumping_object_box [2018/05/03 09:10]
pereira
+++ venting_pumping_object_box [2023/06/02 17:14] (current)
swartzj
@@ 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, and make sure of the following:
-  * Verify that OBJ SCI is not biased:
+  * Before you start, make sure that the gate valves named D2341 BGV and D2303 BGV are closed and that the IG is off.
-        * Check that the detectors is unbiased in the HV module sitting in dU6
+  * The vent valve should also be closed when you begin.
-        * Notify the system of the bias-off state by selecting the "OBJ_SCI_HV CONFIRM" box and clicking "HV CONFIRM OFF"
+  * The valve to the turbo pump TVG should be closed. If the chamber will be vented for a long time, Valve FV should also be closed and the turbo pump should be switched off .
-  * Isolate chamber by closing gate valves **I177GV** and **I190GV**
-  * [[Vacuum control|Turn off]] ion gauge **I188IG**
-  * Check box "PUMPDOWN STATUS BEAMLINE OBJECT BOX". It should read "Good vacuum"
-{{:wiki:objs800vac_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", and then to "VENT VALVE OPEN"
-        * Turbo gate valve **I188GV** will be automatically closed
-        * 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
-        * Go to the S800 OBJ station and slowly open the manual valve (see figure below). You can see the pressure rising in the Granville-Phillips 275 Mini-Convectron display located on top of the OBJ box.
-        * When **I191PG** reads atmospheric pressure select the box "VENT STATUS" and click "STOP VENTING PROCESS"
-        * 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
-        * You can now open the chamber
-{{:wiki:ventingvalveobjbox.jpg?300|Venting valve}}
+The procedure is then as follows:
+  - Close the valve to the roughing pump RV.
+  - Now you can plot the pressure vs time at BPG to monitor the pressure before you open the vent valve.
+  - **Keep a constant eye on the pressure level** as it increases rapidly. When it approaches 800 torr, **it is imperative that you 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.
+  - You can now enter and open the chamber.
+===== Pumping Object 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.
-===== Pumping Object chamber =====
+  * When you start, you should have RV closed, FV open and the TGV valve, Vent valve, as well as the gate valves named D2341 BGV and D2303 BGV all closed.
-Requirements: PanelMate file **S800Vac**
+  * Close FV and 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.
-  * Verify that Chamber is closed and that manual roughing pump valve located near the intermediate-image chamber is closed (see picture above)
+  * 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.
-  * Verify that OBJ SCI is not biased by checking the HV module in dU6
+  * Wait until the vacuum reading at FPG to drops to below 200 mTorr before you can safely turn on the turbo pump.
-  * Open **S800Vac** and go to page 01 ("Production Target Box Vacuum System sec 13")
+  * 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.
-  * Check "PUMPDOWN STATUS INTERMEDIATE BEAMLINE OBJECT BOX"; it should read "PUMPDOWN STOPPED". Select that box and click on "START PUMPDOWN".
+  * 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'.
-  * When the pressure in **I191PG** is below 100 mTorr, the Turbo Pump will start automatically through the following sequence:
+{{ :20230525_155711.jpg?600 |The object chamber vacuum control page}}
-        * **I190RV** will be closed
-        * **I190FV** will be opened
-        * **I188GV** will be opened
-  * When the pressure ready by **I191PG** is few mTorr, you can turn on the ion gauge **I188IG**. Good vacuum will take ~30 minutes.

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