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venting_pumping_object_box [2023/05/25 16:23] swartzj |
venting_pumping_object_box [2023/05/30 16:48] 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 | ||
- | |||
- | {{: | ||
- | |||
+ | 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 if the chamber will be vented for a long time. | ||
+ | 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. 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 ===== | ===== Pumping Object chamber ===== |