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vacuum_control [2014/11/17 10:31] pereira [Target Chamber] |
vacuum_control [2016/11/09 15:29] pereira [Venting analysis-line lower-dipole section] |
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- | The readout from the ion gauges in the S3 vault is available through the control system, but these gauges cannot be turned on and off remotely. They are switched on and off locally by pressing the **EMIS** button on their controllers, | + | The readout from the ion gauges in the S3 vault is available through the control system, but these gauges cannot be turned on and off remotely. They are switched on and off locally by pressing the **EMIS** button on their controllers, |
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All vacuum sections in the in the S800 have automated control of venting and pumpdown that operates valves and pumps (but not ion gauges) in the right sequence with the appropriate delays. In beamline section containing detectors, this automated control must be coordinated appropriately with steps to protect detectors. | All vacuum sections in the in the S800 have automated control of venting and pumpdown that operates valves and pumps (but not ion gauges) in the right sequence with the appropriate delays. In beamline section containing detectors, this automated control must be coordinated appropriately with steps to protect detectors. | ||
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The ion gauge for the [[Stations|Object station chamber]] vacuum system makes too much light for the object scintillator. | The ion gauge for the [[Stations|Object station chamber]] vacuum system makes too much light for the object scintillator. | ||
+ | As stated above (see figure above), this ion-gauge can only be turned off " | ||
===== Target Chamber ===== | ===== Target Chamber ===== | ||
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**Important note**: Ensure that the experimenters never pump the chamber down if the spectrograph vacuum section is vented. The pressure gradient between both sections would " | **Important note**: Ensure that the experimenters never pump the chamber down if the spectrograph vacuum section is vented. The pressure gradient between both sections would " | ||
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+ | ==== 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: | ||
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+ | - 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 with PanelMate. | ||
+ | - Go to page 4 (" | ||
+ | - Window "VENT STATUS" | ||
+ | - Click on "VENT STATUS" | ||
+ | - Walk to the bottom level of the S3 vault, near the intermediate image box. 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. | ||
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===== Spectrograph ===== | ===== Spectrograph ===== | ||
- | This system is pumped with cryopumps. Please do not vent this section if the target chamber is under vacuum pressure. The pressure gradient between both sections would " | + | This system is pumped with cryopumps. Please do not vent this section if the target chamber is under vacuum pressure. The pressure gradient between both sections would " |
===== Focal Plane Box ===== | ===== Focal Plane Box ===== |