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installation_fp_sci [2017/06/20 10:44] pereira [Vent focal-plane chamber] |
installation_fp_sci [2018/04/11 16:26] pereira [Pumping focal-plane chamber] |
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===== Vent focal-plane chamber ===== | ===== Vent focal-plane chamber ===== | ||
* Open the [[hv_bias|HV Remote Control]] GUI and ensure that the focal-plane detectors are unbiased | * Open the [[hv_bias|HV Remote Control]] GUI and ensure that the focal-plane detectors are unbiased | ||
- | * Open the [[gas_handling_system# | + | * Open the [[gas_handling_system# |
* Ensure that the manual venting valve located on the south side of the chamber is closed (see figures below) | * Ensure that the manual venting valve located on the south side of the chamber is closed (see figures below) | ||
* Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]]) | * Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]]) | ||
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{{: | {{: | ||
* Wait until the chamber is vented (few hours). The **I261PG** Pirani Gauge should read slightly above atmospheric pressure (due to the dry N2 flow pumped to the chamber). The window **VENT STATUS** in PanelMate should display "VENT VALVE OPEN". The window **PUMPDOWN STATUS** should display " | * Wait until the chamber is vented (few hours). The **I261PG** Pirani Gauge should read slightly above atmospheric pressure (due to the dry N2 flow pumped to the chamber). The window **VENT STATUS** in PanelMate should display "VENT VALVE OPEN". The window **PUMPDOWN STATUS** should display " | ||
- | * When the chamber is fully vented, close the manual vent valve | + | * When the chamber is fully vented, |
+ | * Close the manual vent valve | ||
===== Open focal-plane chamber ===== | ===== Open focal-plane chamber ===== | ||
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===== Closing focal-plane chamber ===== | ===== Closing focal-plane chamber ===== | ||
* Turn the switch to move the chamber to position " | * Turn the switch to move the chamber to position " | ||
- | * When the chamber is almost | + | * Check the display indicating the weight lift by the hydraulic system. |
+ | * Turn the knob to close the clamps | ||
+ | * Inspect the clamps and chamber flange (no gaps) to ensure that the chamber is properly sealed | ||
* Before pumping the chamber down, make sure that the scintillator is properly connected. This can be done by biasing the detector and checking the signals, either from the scalers or with a scope. One should clearly see cosmic rays; if that is not the case, the phototubes are likely miss connected | * Before pumping the chamber down, make sure that the scintillator is properly connected. This can be done by biasing the detector and checking the signals, either from the scalers or with a scope. One should clearly see cosmic rays; if that is not the case, the phototubes are likely miss connected | ||
===== Pumping focal-plane chamber ===== | ===== Pumping focal-plane chamber ===== | ||
* Make sure that the pressure-relief valve and the manual vent valve (see above) are closed. | * Make sure that the pressure-relief valve and the manual vent valve (see above) are closed. | ||
- | * In order to pumpdown the chamber, start manual pump to get a pressure below 50 mtorr {{: | + | * Make sure that manual |
- | * Close the manual pump; open PanelMate **S800vac** and go to page 07. Select window **PUMPDOWN STATUS** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display " | + | * Open PanelMate **S800vac** and go to page 07. Make sure that the venting valve **I260VV** is closed (see last step of the [[#Vent focal-plane chamber|venting process]] described above) |
- | * Wait for some hours until vacuum is good | + | * Select window **PUMPDOWN STATUS** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display " |
+ | * The vent valve **I260VV** and foreline valve **I260FV** will be automatically closed | ||
+ | * After the rough valve **I260RV** is automatically open, the mechanical pump will start pumping. | ||
+ | * The pressures in the mechanical pump (from **I259PG**) and beam chamber (from **I261PG**) will jump momentarily to very high values. They should go down slowly after few seconds (otherwise, the chamber is not properly closed). | ||
+ | * When pressure in the chamber (from **I261PG**) gets below 100 mTorr (at least 30 min), **I260RV** will close. Foreline valve **I260FV** will open followed by the turbo gate valve **I260GV**. | ||
+ | * Wait for few hours until vacuum is good. You can then turn on the ion gauge **I264IG** | ||
+ |