S800 Documentation

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====== Venting/pumping lower-dipole section ======

===== Venting analysis-line lower-dipole section =====
In order to ensure that the beamline in the target area is properly aligned with respect to the beam axis, it is necessary to install a telescope in between the last two quadrupoles of the analysis line, as well as a "cross hair" plate in between the last quadrupole and the target chamber. Although the alignment of the telescope is done by lab staff (e.g. Dave Sanderson), the user is responsible for removing the gate valve I246GV separating the analysis line and the target area. This of course, requires that the lower-dipole section is properly vented. The venting process is generally done by the device physicist, following the steps:

  - Verify that the target area is vented.
  - Using the EMIS controllers in the middle level of the S3 vault (see figure above), ensure that the ion gauge I225IG is turned off.
  - Ensure that gate valves I246GV (between lower-dipole section and target area) and I215GV (between intermediate image area and the lower-dipole section) are closed.
  - Open **S800vac** PanelMate.
  - Go to page 4 ("lower beamline dipoles vacuum system, section 16")
  - Window "VENT STATUS" should be green and display "GOOD VACUUM"
  - Click on "VENT STATUS" and select "BEGIN VENTING PROCEDURE". The I225GV turbo gate valve will be automatically closed (see figure below). However, the venting process won't be complete until you open the manual valve.
  - Walk to the bottom level of the S3 vault, right downstream of the last two dipoles of the analysis line. Locate the I226PG Pirani gauge and ensure that it reads rough-vacuum pressure (few militorr).
  - Slowly open the manual valve (see picture below) and verify that the pressure read in I226PG raises slowly.
  - After the section is vented (atmospheric pressure) close the manual gate valve.


{{:wiki:panelmates800vac-ventinglowerdipoles.jpg?600|PanelMate s800va (page 4) displaying venting status of lower-dipole section}}


{{:wiki:manualvalve-lowerdipoles.jpg?600|Manual venting valve of lower-dipole section}}


===== Pumping analysis-line lower-dipole section =====
  * Make sure that the manual gate valve is closed (see above).
  * Open PanelMate **S800vac** and go to page 04. Make sure that the venting valve **I225VV** is closed (see last step of the [[#Vent focal-plane chamber|venting process]] described above)
  * Select window **PUMPDOWN STATUS SECTION 16-LOWER DIPOLES** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display "PUMPDOWN IN PROGRESS"
       * After the rough valve **I225RV** is automatically open, the mechanical pump will start pumping.
       * The pressures in the mechanical pump (from **I224PG**) and beam chamber (from **I226PG**) will jump momentarily to high pressure values. They should go down slowly after few seconds (otherwise, the chamber is not properly closed).
       * When pressure in the chamber (from **I226PG**) gets below 100 mTorr (few minuntes), **I225RV** will close. Foreline valve **I225FV** will open followed by the turbo gate valve **I225GV**.
  * Wait for few hours until vacuum is good. You can then turn on the ion gauge **I225IG**
S800 Documentation

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