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installation_fp_sci [2017/06/20 10:41]
pereira [Vent focal-plane chamber]
installation_fp_sci [2017/06/22 11:58] (current)
pereira [Pumping focal-plane chamber]
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 {{:​wiki:​fp-pirani.jpg?​350|FP chamber manual venting valve}} ​ {{:​wiki:​fp-pirani.jpg?​350|FP chamber manual venting valve}} ​
   * 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 "​PUMPDOWN STOPPED"​   * 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 "​PUMPDOWN STOPPED"​
 +  * When the chamber is fully vented, select **VENT STATUS** and click **STOP VENTING PROCEDURE**. This will automatically close the vent valve **I260VV**
 +  * 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 "​UP",​ and keep it that way for about 10 minutes (the time it takes the chamber to be closed)   * Turn the switch to move the chamber to position "​UP",​ and keep it that way for about 10 minutes (the time it takes the chamber to be closed)
-  * When the chamber is almost ​close, ​turn the know to close the clamps+  * Check the display indicating the weight lift by the hydraulic system. ​When the chamber is close, the weight displayed will increase drastically due to the resistance experienced by the hydraulic system. At that point, stop immediately the lifting switch (otherwise, a weight-limit set point might be reached, disabling 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 (see above) ​is in place (closed)+  * Make sure that the pressure-relief ​valve and the manual vent valve (see above) ​are closed. 
-  * In order to pumpdown the chamber, make sure that the manual ​vent valve is closed. Start manual ​pump to get a pressure below 50 mtorr {{:​wiki:​ManualValve-fp.jpg?​350|Manual valve pump}} +  * Make sure that manual valve of the mechanical ​pump is opened (the valve **I260RV** will be automatically opened in the next step) {{:​wiki:​ManualValve-fp.jpg?​350|Manual valve pump}} 
-  * 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 "​PUMPDOWN IN PROGRESS"​ +  * 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 "​PUMPDOWN IN PROGRESS"​ 
 +       * 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** 
 + 
installation_fp_sci.1497969669.txt.gz · Last modified: 2017/06/20 10:41 by pereira