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venting_pumping_intermediate_image_box [2017/06/12 14:25] pereira [Venting/pumping Intermediate Image box and filling PPACs with gas] |
venting_pumping_intermediate_image_box [2018/04/16 16:13] pereira |
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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 safely. 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 (NOTE: This figure was taken from the A1900 GHS included in Barney. A similar GUI for the S800 II PPACs is not yet available): |
{{: | {{: | ||
- | The II-GHS equipment (valves, flow-meter, pipes, etc.) are located on the west balcony of the top level in the S3 vault (see figure below): | + | The II-GHS equipment (valves, flow-meter, pipes, |
{{: | {{: | ||
- | ==== Vent focal-plane chamber ==== | + | |
- | * Open the [[hv_bias|HV Remote Control]] GUI and ensure | + | |
- | * Open the [[gas_handling_system# | + | |
- | * Ensure that the manual | + | |
- | * Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]]) | + | |
- | * Open PanelMate | + | |
- | * Gently open the manual | + | |
- | {{:wiki:fp-pirani.jpg?350|FP chamber manual venting | + | ===== Vent Intermediate-image chamber |
- | * Wait until the chamber | + | Requirements: |
+ | |||
+ | * Verify that PPACs are in automatic mode with gas removed (**S3_Gas_Handling**) | ||
+ | * The "GH System Status box should read "Auto Mode Gas Removed" | ||
+ | * If gas is removed but the system is not in the automatic mode, consult the Beam Physicists or Device Physicist. NOTE: the only valves that should be open in **S3_Gas_Handling** are the "Det Bypass" | ||
+ | * Verify that PPACs are not biased: | ||
+ | * Check that the detectors are unbiased | ||
+ | * Notify | ||
+ | | ||
+ | | ||
+ | | ||
+ | * Check box " | ||
+ | {{: | ||
+ | * In order to begin venting | ||
+ | * Box "VENT STATUS" | ||
+ | * Turbo gate valve **I214GV** will be automatically | ||
+ | * When **I215PG** reads atmospheric pressure, select the box "VENT STATUS" | ||
+ | |||
+ | | ||
+ | * You can now open the chamber | ||
+ | |||
+ | |||
+ | ===== Pumping Intermediate-image chamber ===== | ||
+ | Requirements: | ||
+ | * Verify that Chamber is closed | ||
+ | * Verify that PPACs are not biased by opening | ||
+ | * IMPORTANT: Close manual | ||
+ | |||
+ | * 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). | ||
+ | | ||
+ | * Check " | ||
+ | * Slowly crack manual roughing valve | ||
+ | * Start slow (< 1 Torr/sec). Chamber pressure is displayed in **I215PG** in **S800Vac** | ||
+ | * Verify PPACs changing shape through sighting | ||
+ | | ||
+ | | ||
+ | | ||
+ | * **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: it sometimes happens that the foreline pressure rises above the trip point for the Turbo Pump (e.g. if the pumpdown timer expires before pressure is below 300 mTorr). In this case the foreline valve needs to be bypassed open (in PanelMate) and the TP needs to be restarted. | ||
+ | * At the end of the procedure, close the manual roughing pump valve | ||