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installation_fp_sci [2019/04/28 18:17]
pereira [Vent focal-plane chamber]
installation_fp_sci [2019/07/01 09:46] (current)
pereira [Pumping focal-plane chamber]
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 ====== Installation of focal-plane scintillator ====== ====== Installation of focal-plane scintillator ======
  
 +In June 2019, a new Turbo Pump with magnetically-levitating bearings (Leybold MAG 2200iP) was installed in the S800 focal-plane chamber. This pump has a dry-N line connected to it that is purging continuously the bearings. This creates an extra pressure in the foreline, which must be pumping down continuously. Therefore, it is critical turn off the turbo pump whenever the foreline valve needs to be closed.
 +
 +Instructions on how to vent/​pump-down the focal-plane chamber are described below.
 ===== 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
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   * 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 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]])   * 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. +  * Open PanelMate and select **S800vac** file in directory \\exp\files\control\ncsdata\General\Qt\Templates, and go to page 07 (see figure below)  
-  * 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+{{:​wiki:​NewPanelMate-S800FPVac.jpg?​950|Panel Mate Vacuum FP chamber}} 
 +  * Close 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. The turbo GV **I260GV** will be closed, isolating the turbo pump from the focal-plane chamber.
   * 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) ​   * 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}} ​ {{:​wiki:​fp-pirani.jpg?​350|FP chamber manual venting valve}} ​
 +  * Make sure that pressure inside the CRDCs and IC detectors (LabView) increase at the same rate than the pressure in the chamber. Otherwise, stop the venting process inmediately.
   * 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"​
 +  * Meanwhile, turn the turbo pump off using PanelMate **S800vac**:​ select box **Turbo pump focal plane detector I260TP** can clock "​Stop"​. It will take several minutes to fully stop (you can check the turbo-pump speed in box **I260TP SPEED**, or using EPICS channel **I260TP_FR_RD**)
 +  * When the Turbo pump is fully stopped, switch off the chiller located near the S800 electronics rack
   * When the chamber is fully vented, select **VENT STATUS** and click **STOP VENTING PROCEDURE**. This will automatically close the vent valve **I260VV**   * 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   * Close the manual vent valve
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   * 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.
   * 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}}   * 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 the gas-handling-system LabView control and make sure that the only open detector valves are **4** (IC supply), **5** (IC bypass), **6** (IC focal-plane bypass), **7** (Ion Chamber vent), **20** (CRDC supply), **21** (CRDC bypass), and **22** (CRDC focal-plane bypass) and **23** (CRDC vent). The rest of the valves should be closed. The pressure inside the detectors should be ~760 Torr.
   * 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)   * 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)
 +  * Make sure that the turbo pump is off (as seen in PanelMate **s800vac**,​ page 07, box **Turbo pump focal plane detector I260TP**)
   * Select window **PUMPDOWN STATUS** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display "​PUMPDOWN IN PROGRESS"​   * Select window **PUMPDOWN STATUS** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display "​PUMPDOWN IN PROGRESS"​
        * The vent valve **I260VV** and foreline valve **I260FV** will be automatically closed        * 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.+       * 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).        * 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**.+       * Make sure that pressure inside the CRDCs and IC (LabView) decrease at the same rate as the chamber. Otherwise, stop the pump-down sequence immediately. 
 +       * Note that during the rough pump-down sequence, pressure in the foreline I260PG will increase to few torr due to the purge line connected to the turbo pump. This is ok, as long as the turbo pump is OFF 
 +       * When pressure in **I261PG** is ~95 mTorr, turn on the chiller providing cooling water to the turbo pump.  
 +       * When pressure in the chamber (from **I261PG**) gets below 90 mTorr (at least 45 min), **I260RV** will close. 
 +       * Open the foreline ​valve **I260FV** ​using PanelMate box **Foreline vlve I260FV ** and clicking "​Open"​ 
 +       * When pressure in the foreline (**I260PG**) is below 200 mTorr, turn on the turbo pump. You will see the speed increasing in the PanelMate box **I260TP speed** 
 +       * It takes about 8 min to get the turbo pump "At Speed" (as read in box **Turbo pump focal plane detector I260TP**). During that time, the pressure in the focal-plane chamber will slowly increase (it is not being pump down) by few mTorr 
 +       * When the turbo pump is "At Speed" and pressure in the chamber (as read in **I261PG**) is below 175 mTorr, ​the turbo-pump gate valve **I260GV** ​will open 
 +       * After **I260GV** gets opened, you will see a pressure spike in the foreline **I260PG** up to ~1 Torr. This is normal behavior. This pressure will slowly decrease below 200 mTorr in about 2 minutes. It will take at least 30 min to reach the nominal value (~60 mTorr)
   * Wait for few hours until vacuum is good. You can then turn on the ion gauge **I264IG**   * Wait for few hours until vacuum is good. You can then turn on the ion gauge **I264IG**
    
installation_fp_sci.1556489832.txt.gz · Last modified: 2019/04/28 18:17 by pereira