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venting_pumping_intermediate_image_box [2017/06/13 15:40] pereira [Pumping Intermediate-image chamber] |
venting_pumping_intermediate_image_box [2018/12/20 15:12] pereira [Filling/Removing gas in Intermediate-image delay PPAC] |
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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: | + | * [[#General information]] |
+ | * [[#Vent Intermediate-image chamber|Venting Intermediate-image chamber]] | ||
+ | * [[#Pumping Intermediate-image chamber]] | ||
+ | * [[# | ||
+ | |||
+ | ===== General information ===== | ||
+ | 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, |
{{: | {{: | ||
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* Check that the detectors are unbiased by opening the [[HV bias|HV GUI]] | * Check that the detectors are unbiased by opening the [[HV bias|HV GUI]] | ||
* Notify the system of the bias-off state by selecting the " | * Notify the system of the bias-off state by selecting the " | ||
+ | * Open **S800Vac** and go to page 03 (" | ||
* Isolate chamber by closing gate valves **I212GV** and **I215GV** | * Isolate chamber by closing gate valves **I212GV** and **I215GV** | ||
* [[Vacuum control|Turn off]] ion gauge **I213IG** | * [[Vacuum control|Turn off]] ion gauge **I213IG** | ||
- | * Open **S800Vac** and go to page 03 (" | ||
* Check box " | * Check box " | ||
{{: | {{: | ||
- | * In order to begin venting process, select | + | * In order to begin venting process, select box "VENT STATUS" |
* 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**) {{: | ||
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* 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 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]] | * Verify that PPACs are not biased by opening the [[HV bias|HV GUI]] | ||
- | * IMPORTANT: | + | * IMPORTANT: |
* 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). | * 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 (" | * Open **S800Vac** and go to page 03 (" | ||
- | * Check " | + | * Check " |
* Slowly crack manual roughing valve | * Slowly crack manual roughing valve | ||
- | * Start slow (< 1 Torr/ | + | * Start slow (< 1 Torr/ |
- | * Verify PPACs changing shape through sighting window | + | * Verify PPACs changing shape through sighting window. |
- | * When PPACs equalize, increase | + | * Pump to about 100 Torr before fully opening the roughing valve. |
* Once roughing valve is fully open, retract PPACs and turn lights off. | * 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: | * When the pressure in **I215PG** is below 200 mTorr, the Turbo Pump will start automatically through the following sequence: | ||
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* **I214GV** 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. | * 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 | + | * 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, or there is too much back-up pressure from the chamber when the foreline valve opens). In this situation, you will see that: (1) the turbo pump will stop, (2) the turbo gate valve **I214GV** will be closed, (3) the foreline valve **I214FV** will be closed and the corresponding PanelMate box will turn red and display an error message " |
+ | * Select box labeled " | ||
+ | * Select box labeled "TURBO PUMP INTERMEDIATE IMAGE BOX I214TP" | ||
+ | * Turbo pump will start ramping speed. When the TP reaches 40000 RPM, the **I214GV** will open automatically. | ||
+ | * When foreline vacuum gets below 2 Torr, you can select " | ||
+ | * (Note: sometimes it is necessary to repeat this operation a couple of times). | ||
* At the end of the procedure, close the manual roughing pump valve | * At the end of the procedure, close the manual roughing pump valve | ||
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+ | |||
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+ | ===== Filling/ | ||
+ | |||
+ | {{: | ||
+ | |||
+ | Requirements: | ||
+ | |||
+ | ==== Filling Intermediate-image delay PPAC with gas ==== | ||
+ | * Verify that PPACs are not biased: | ||
+ | * Check that the detectors are unbiased by opening the [[HV bias|HV GUI]] | ||
+ | * Notify the system of the bias-off state by selecting the " | ||
+ | * Verify that ion gauge I213IG is off | ||
+ | * 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. This typically requires to verify that the system is in a controlled status. In particular, the " | ||
+ | * Confirm that PanelMate box " | ||
+ | * Open the gas bottle valve (sitting near the gas handling system) | ||
+ | * PanelMate box "Gas Flow Control" | ||
+ | * Valve V2 (Gas lin pmp out) will be opened and I214V_NCL will change from closed to " | ||
+ | * Valves V3 (Flow Bypass) and V4 (Det Return) will open | ||
+ | * Valve V1 (Gas supply) will open, and V2, V3, and V6 (Chamber Bypass) will close | ||
+ | * GH System status should indicate "Gas Flowing" | ||
+ | * I214CM Press Rdg will gradually increase to the set value | ||
+ | * When the detector is filled, valve V5 (Det Bypass) will close | ||
+ | * GH System status will indicate "Flow Estab." | ||
+ | * I214BON_CONFIM will change to "PPAC BIAS ASSUMED ON" | ||
+ | * The valves status will be: V1 (open), V2 (closed), V3 (closed), V4 (open), V5 (closed), V6 (closed, I214V_NCL (enabled) | ||
+ | * You can now turn on the detectors | ||
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+ | ==== Removing gas from Intermediate-image delay PPAC ==== | ||
+ | * Verify that PPACs are not biased: | ||
+ | * Check that the detectors are unbiased by opening the [[HV bias|HV GUI]] | ||
+ | * Notify the system of the bias-off state by selecting the " | ||
+ | * Verify that PPACs are in automatic mode with gas flowing (**S3_Gas_Handling**) | ||
+ | * The "GH System Status box should read "Auto Gas Flow Estab" | ||
+ | * If gas is flowing but the system is not in the automatic mode, consult the Beam Physicists or Device Physicist. This typically requires to verify that the system is in a controlled status. In particular, the " | ||
+ | * I214 Gas Sup V1 (open) | ||
+ | * Gas Lin Pmp out V2 (closed) | ||
+ | * Flow Bypass V3 (closed) | ||
+ | * Det Return V4 (open) | ||
+ | * Det Bypass V5 (closed) | ||
+ | * Chmbr Bypass (closed) | ||
+ | * I1214V_NCL (enabled) | ||
+ | * PanelMate box "Gas Removal Control" | ||
+ | * Valves V1 (I214 Gas Sup) and I214V_NCL will close | ||
+ | * Valves V3 (Flow Bypass) and Det Bypass (V5) will open | ||
+ | * I214CM Press Rdg will gradually decrease to zero | ||
+ | * GH System status should indicate "Gas Removal" | ||
+ | * When the gas is removed from the detector | ||
+ | * Valve V3 (Flow Bypass) and 4 (Det return) will close | ||
+ | * Valve V6 (Chamber Bypass) will open | ||
+ | * GH System status will indicate "Gas Removed" | ||
+ | * I214BON_CONFIM will change to "PPAC BIAS ASSUMED ON" | ||
+ | * The valves status will be: V1 (closed), V2 (closed), V3 (closed), V4 (closed), V5 (open), V6 (open), I214V_NCL (closed) | ||
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