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venting_pumping_object_box [2023/05/25 16:10] swartzj |
venting_pumping_object_box [2023/05/30 14:32] swartzj |
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===== Vent Object chamber ===== | ===== Vent Object chamber ===== | ||
- | Requirements: | ||
- | |||
- | * Open **S800Vac** and go to page 01 (" | ||
- | * Verify that OBJ SCI is not biased: | ||
- | * Check that the detectors are unbiased in the HV module sitting in dU6 | ||
- | * Notify the system of the bias-off state by selecting the " | ||
- | * Isolate chamber by closing gate valves **I177GV** and **I190GV** | ||
- | * [[Vacuum control|Turn off]] ion gauge **I188IG** | ||
- | * Check box " | ||
- | * Go to the S800 OBJ station and make sure that the manual valve (see figure below) is closed. | ||
- | |||
- | {{: | ||
- | * In order to begin venting process, select box "VENT STATUS" | ||
- | * Box "VENT STATUS" | ||
- | * Turbo gate valve **I188GV** will be automatically closed | ||
- | * Vent valve **I190VV** will be automatically opened. However, the pressure in the chamber (as 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" | ||
- | * The status in the box "VENT STATUS" | ||
- | * Close the manual valve | ||
- | * You can now open the chamber | ||
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- | {{: | ||
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+ | 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: | ||
+ | * Before you start, make sure that the gate valves named D2341 BGV and D2303 BGV are closed and that the IG is off. | ||
+ | * The vent valve should also be closed when you begin. | ||
+ | * Both valves to the turbo pump should be closed and the turbo pump should be switched off. | ||
+ | The procedure is then as follows: | ||
+ | - Close the valve to the roughing pump RV. | ||
+ | - Now you can plot the pressure at BPG to monitor the pressure before you open the vent valve. | ||
+ | - **Keep a constant eye on the pressure level** as it increases rapidly. Before it nears 800 torr, **it is imperative that you close the venting valve.** Failure to do so will result in over pressure since the chamber will continue to be filled with dry nitrogen. | ||
+ | - You can now enter and open the chamber. | ||
===== Pumping Object chamber ===== | ===== Pumping Object chamber ===== | ||
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* 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. | * 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. | ||
* Close FV and open RV to start pumping down the object chamber with the roughing pump. You can make a plot of the pressure at BPG at this point. | * Close FV and open RV to start pumping down the object chamber with the roughing pump. You can make a plot of the pressure at BPG at this point. | ||
- | * Wait for the vacuum | + | * Section D2337 will initially be red with vacuum status: 'Bad vacuum' |
- | * The vacuum reading at FPG needs to drop to below 150 mTorr before you can safely turn on the turbo pump. | + | * The vacuum reading at FPG needs to drop 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. | * 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. | + | * 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' |
- | + | {{ :20230525_155711.jpg? | |
- | {{:wiki:|Object | + | |