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--- installation_fp_sci [2018/04/11 16:26]
pereira [Pumping focal-plane chamber]
+++ installation_fp_sci [2019/07/01 09:28]
pereira [Vent focal-plane chamber]
@@ Line 1: / Line 1: @@
 ====== 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 =====
   * 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), **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
+  * Open the [[gas_handling_system#labview_control_program|Labview gas handling system]] and verify that there is no gas in the CRDCs and IC. Make sure that the only open 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
   * 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.
+  * 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)
 {{: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"
+  * 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**
   * Close the manual vent valve

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