venting_pumping_intermediate_image_box
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venting_pumping_intermediate_image_box [2017/06/12 14:54] pereira |
venting_pumping_intermediate_image_box [2017/06/13 12:57] pereira [Pumping Intermediate-image chamber] |
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| - | ===== Venting/ | + | ====== Venting/ |
| 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: | 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: | ||
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| - | ==== Vent focal-plane chamber ==== | + | ===== Vent Intermediate-image chamber |
| Requirements: | Requirements: | ||
| Line 27: | Line 27: | ||
| * Open **S800Vac** and go to page 03 (" | * Open **S800Vac** and go to page 03 (" | ||
| * Check box " | * Check box " | ||
| - | {{: | + | {{: |
| * In order to begin venting process, select that box and click "BEGIN VENTING PROCEDURE" | * In order to begin venting process, select that box and click "BEGIN VENTING PROCEDURE" | ||
| * Box "VENT STATUS" | * Box "VENT STATUS" | ||
| - | * Turbo gate valve **I214GV** will be automatically closed and pressure in chamber will start rising (as seen in **I215PG**) {{: | + | * Turbo gate valve **I214GV** will be automatically closed and pressure in chamber will start rising (as seen in **I215PG**) {{: |
| - | * When **I215PG** reads atmospheric pressure, select the box "VENT STATUS" | + | * When **I215PG** reads atmospheric pressure, select the box "VENT STATUS" |
| * The status in the box "VENT STATUS" | * The status in the box "VENT STATUS" | ||
| * You can now open the chamber | * You can now open the chamber | ||
| + | |||
| + | |||
| + | ===== Pumping Intermediate-image chamber ===== | ||
| + | Requirements: | ||
| + | * Verify that Chamber is closed and pressure-relief valve (north side of the chamber) is properly closed (NOTE: sometimes, due to overpressure from dry N2 during the venting procedure, the O-ring in pressure-relief valve flange is moved out of place) | ||
| + | * Verify that PPACs are not biased by opening the [[HV bias|HV GUI]] | ||
| + | * IMPORTANT: Close manual roughing pump valve close to the Intermediate-image chamber | ||
| + | * Insert PPACs/turn on light (Diagnostic Drives PanelMate) and verify condition through sight window on south side of the chamber (be careful no to bump the bullet camera). | ||
| + | * Open **S800Vac** and go to page 03 (" | ||
| + | * Check " | ||
| + | * Slowly crack manual roughing valve | ||
| + | * Start slow (< 1 Torr/sec). Pressure is displayed in the digital display of the Granville-Phillips 275 Mini-Convectron gauge, sitting on top of the chamber (or in **I215PG** in **S800Vac** PanelMate) | ||
| + | * Verify PPACs changing shape through sighting window | ||
| + | * When PPACs equalize, increase to 5 Torr/sec | ||
| + | * Once roughing valve is fully open, retract PPACs and turn lights off. | ||
| + | * When the pressure in **I215PG** is below 200 mTorr, the Turbo Pump will start automatically through the following sequence: | ||
| + | * **I214RV** will be closed | ||
| + | * **I214FV** will be opened | ||
| + | * **I214GV** will be opened | ||
| + | * When the pressure ready by **I215PG** is few mTorr, you can turn on the ion gauge **I213IG**. Good vacuum will take ~1-2 hours. | ||
| + | * NOTE: WHAT TO DO IF PUMPDOWN TIMER EXPIRES BEFORE TURBO PUMP IS ON | ||
venting_pumping_intermediate_image_box.txt · Last modified: 2024/01/12 09:37 by noji
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