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venting_pumping_intermediate_image_box [2018/08/14 10:52] pereira [Pumping Intermediate-image chamber] |
venting_pumping_intermediate_image_box [2018/12/19 11:10] pereira [Filling Intermediate-image delay PPAC] |
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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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* (Note: sometimes it is necessary to repeat this operation a couple of times). | * (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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+ | ===== Filling Intermediate-image delay PPAC ===== | ||
+ | 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 | ||