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venting_pumping_intermediate_image_box [2018/04/25 17:14] pereira [Pumping Intermediate-image chamber] |
venting_pumping_intermediate_image_box [2018/12/19 11:07] pereira [Venting/pumping Intermediate Image box and filling PPACs with gas] |
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====== Venting/ | ====== Venting/ | ||
+ | * [[#General information]] | ||
+ | * [[#Vent Intermediate-image chamber|Venting Intermediate-image chamber]] | ||
+ | * [[#Pumping Intermediate-image chamber]] | ||
+ | * [[#Filling Intermediate-image delay PPAC]] | ||
+ | |||
+ | ===== 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 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): | ||
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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 " | ||
{{: | {{: | ||
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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: 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 **I214GV** will be closed and the corresponding PanelMate box will turn red and display an error message " | + | * 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 | ||