S800 Documentation

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====== Installation of focal-plane scintillator ======

===== Vent focal-plane chamber =====
  * Open the [[hv_bias|HV Remote Control]] GUI and ensure that the focal-plane detectors are unbiased
  * Open the [[gas_handling_system#labview_control_program|Labview gas handling system]] and verify that there is no gas in the CRDCs and IC. Open valves **4** (IC supply), **5** (IC bypass), **6** (IC focal-plane bypass), **20** (CRDC supply), **21** (CRDC bypass), and **22** (CRDC focal-plane bypass). The rest of the valves should be closed
  * Ensure that the manual venting valve located on the south side of the chamber is closed (see figures below)  {{:wiki:fp-venting-valve-Daniel.jpg?350|FP chamber manual venting valve}} {{:wiki:fp-venting-valve.jpg?350|FP chamber manual venting valve}}
  * Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]])
  * Open PanelMate and select **S800vac** file in directory \\exp\files\control\ncsdata\General\Qt\Templates. Go to page 07, and ensure that I265GV (gate valve separating FP box from rest of beam line) is closed.
  * Click on the **VENT STATUS** window and begin the venting procedure. The **VENT VALVE I260VV** window will turn red and display "OPEN". The pressure should remain constant because the manual venting valve is still closed
  * Gently open the manual venting valve until the pressure displayed in the Pirani Gauge (see figure below) increases by ~1 torr every 15 seconds (see figures below) 
{{: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"
  * 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 =====

  * After venting the FP chamber, the pressure inside the chamber is slightly above atmospheric due to the dry N2 pumped. Before opening the chamber, it is recommended to vent the extra N2 by "forcing" the pressure-relief valve  with e.g. a screwdriver {{:wiki:screwdriver-flange.jpg?350}}
  * Unlock the padlock protecting the power brakers of the switch controls to open the chamber, and press the **START** button {{:wiki:padlock-note.jpg?350|Padlock}}
  * Turn the switch to open the clamps holding the FP chamber. The weight held by the hydraulic piston will increase {{:wiki:switch-clamps.jpg?250|Switch clamps}} {{:wiki:clamps.jpg?400|Clamps holding FP chamber}} {{:wiki:scale.jpg?350|Scale FP chamber}}
  * Turn on the switch to activate the motor opening the chamber. It takes about 10 minutes to get the chamber totally opened {{:wiki:fp-chamber-motor.jpg?250|Motor switch to open FP chamber}}


===== Installing FP scintillator =====

  * The figure below shows the FP chamber open, with the "old" FP scintillator to be replaced by the new one {{:wiki:E1-view.jpg?350|FP chamber opened}}
  * Unplug the bases of the up and down phototubes. The platic tie holding the cable of the up phototube to the chamber needs to be cut {{:wiki:e1-up-Daniel.jpg?400|UP base phototube}}   {{:wiki:e1-down-closeup.jpg?250|DOWN base phototube}}
  * Using an allen wrench, unscrew the two bolts attaching the scintillator frame to the base of the chamber {{:wiki:e1-frame-bolts.jpg?350|Scintillator frame}}
  * Climb to the chamber and pull the scintillator frame up. Once unplugged, handle it to a second person {{:wiki:Daniel-Jorge-1.jpg?350|FP chamber opened}} {{:wiki:Daniel-Jorge-2.jpg?350|FP chamber opened}}
  * With the help of a second person, hold the new scintillator by its frame and place it in the right spot. A second person should be ready to screw the frame to the base of the chamber
  * Connect the bases of the up and down phototubes. The later is quite difficult because one cannot see the pins
  * Using a plastic tie, attach the cable of the up phototube to the scintillator frame





===== 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)
  * 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

===== Pumping focal-plane chamber =====
  * Make sure that the pressure-relief valve and the manual vent valve (see above) are closed.
  * 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}}
  * 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)
  * 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, **I260RV** will close. Foreline valve **I260FV** will open followed by the turbo gate valve **I260GV**.
  * The pressures in the mechanical pump (from **I259PG**) and beam chamber (from **I261PG**) will jump momentarily to very high values. They should go down after few seconds
  * Wait for some hours until vacuum is good
S800 Documentation

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