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installation_fp_sci [2017/06/13 12:19] pereira |
installation_fp_sci [2023/08/18 10:19] (current) noji [Zeroing PTs] |
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- | ====== | + | ====== |
- | ===== Vent focal-plane chamber | + | //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.// |
- | * Open the [[hv_bias|HV Remote Control]] GUI and ensure that the focal-plane detectors are unbiased | + | |
- | | + | The GHS for the focal plane is operated remotely through CS studio. Its page can be found on the EXP network through FRIB EXP Main → S800 → GHS Pages (Secondary Pages) → FP Main Page and is shown below. |
- | | + | |
- | * Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]]) | + | {{: |
- | * Open PanelMate | + | |
- | * Gently open the manual venting valve until the pressure displayed | + | Here are screenshots of the " |
- | {{:wiki:fp-pirani.jpg?350|FP chamber manual venting valve}} | + | {{: |
- | * Wait until the chamber | + | {{: |
+ | |||
+ | Instructions on how to vent/ | ||
+ | |||
+ | ===== Emptying Detectors ===== | ||
+ | | ||
+ | - Return to “GHS_FP_Main” click **Enable MFC Controls** | ||
+ | - Set MFC1 to 0 sccm to stop the flow of P10 to the IC vessel | ||
+ | - Set MFC2 to 0 sccm. This will cause MFC3 to also go to zero through the ratio control. The flow of iC4H10 and CF4 to the CRDC chamber will cease. | ||
+ | - Click **Enable Controls** for the CRDC and IC Control Valve PIDs and then click **DISABLE** for each of them. This will open the control valve to 100% for each vessel and begin pumping them out. | ||
+ | - The IC vessel has a much larger quantity of gas compared to the CRDC vessel. In order to pump them out at a similar speed go to the “FP_State_Buttons” page and go to the D2708 (Ion Chamber) tab. Click **EMPTY**. This will more rapidly pump down the IC vessel. Both vessels should be emptied at about the same time. | ||
+ | - Open a data browser and plot the PVs for PT1 (S800_GHS: | ||
+ | | ||
+ | - Open the Focal Plane VAC D2686 page (FRIB EXP Main → S800 → Vacuum Main → Focal Plane). | ||
+ | - Ensure | ||
+ | | ||
+ | - Notify the Control Room that EXP alarms may occur. | ||
+ | - On the “FP_State_Buttons” page, click VENT mode for both D2703 (CRDCs) and D2708 (Ion Chamber). | ||
+ | - The detector volumes will be bypassed to the chamber. The TGV and TMP should handle the gas load and quickly pump the chamber back to high vacuum. If any issues occur, contact the Rare Isotope Operations Vacuum Group. | ||
+ | - The IG may turned back on once the BPG reads < 5 mTorr. | ||
+ | - The GHSs can remain in this state until they need to be filled again. | ||
+ | |||
+ | ===== Venting FP Chamber ===== | ||
+ | |||
+ | Notify | ||
+ | |||
+ | - Ensure the IG in the Focal Plane Pumping Station | ||
+ | - Check the box next to “Valve Controls”, | ||
+ | - Turn the TMP off. | ||
+ | - Ensure both CRDCs and IC are in *VENT* mode | ||
+ | - Plot PT1 (S800_GHS:CMG_D2708A:VP_RD), PT2 (S800_GHS: | ||
+ | | ||
+ | | ||
+ | | ||
+ | |||
+ | The CRDC (Purple) and IC (Green) vessel pressures during Emptying and Venting procedures outlined above are shown below. | ||
+ | |||
+ | {{:wiki:crdc_ic_pressures_during_empty_vent.png|}} | ||
+ | |||
+ | ===== Pumpdown of FP Chamber ===== | ||
+ | |||
+ | | ||
+ | - Open “GHS_FP_Main” and “FP_State_Buttons” pages from FRIB EXP Main → S800 → GHS Pages (Secondary Pages). | ||
+ | - Plot PT1 (S800_GHS: | ||
+ | - On the “FP_State_Buttons” page change from “Vent” mode to “Pump” mode by clicking | ||
+ | - Check the box next to “Valve Controls” on the “Focal Plane VAC D2686” page. | ||
+ | - Ensure the TMP is **off** and Foreline Valve (FV) is closed. Open the Roughing Valve (RV) briefly (2 seconds) by clicking **Open** and observe the behavior of the pressure gauges. If they all decrease at the same rate, again click **Open** to begin roughing out the chambers. | ||
+ | | ||
+ | - Once the BPG reads < 5 mTorr, the IG may be turned on. | ||
+ | |||
+ | ===== Filling & Running Detectors ===== | ||
+ | |||
+ | - Ensure that the FP chamber is under high vacuum, detectors are bypassed | ||
+ | - On the “FP_State_Buttons” page click **RUN** | ||
+ | - Plot PT1 (S800_GHS: | ||
+ | - Click **Enable Controls** for the CRDC and IC “Control Valve PID”s, then click **ENABLE** to turn on PID controls for each vessel. Each control valve should adjust to its BASE value. | ||
+ | - If the CRDC valve remains completely open (stuck at 100%), open a probe with PV: “S800_GHS: | ||
+ | - Click **Enable MFC Controls**. | ||
+ | - Set MFC1 to 25 sccm. Ensure PT1 begins to increase in pressure. | ||
+ | - Set MFC2 to 8 sccm. Ensure MFC3 automatically sets to 32 sccm and PT2 begins to increase in pressure. | ||
+ | - The IC vessel is a much larger chamber than the CRDC vessel and needs to reach a higher operating | ||
+ | | ||
+ | - If CSET is not set to 40 Torr, decrease MFC2 at **5 Torr** below the setpoint. | ||
+ | - As the vessels approach their setpoints the Control Valves should begin to increase from their BASE values | ||
+ | | ||
+ | - Once PT1 reaches **300 Torr**, adjust MFC1 back to 25 sccm by selecting “Go to MFC Setpoint” in the dropdown menu next to MFC1. The pressure will equilibrate down to about **299.5 Torr**. Allow the IC vessel to slowly approach 300 Torr. Use the figure below for reference.{{: | ||
+ | - If CSET is not set to **300 Torr**, adjust MFC1 back to 25 sccm when the setpoint is reached. | ||
+ | - The control valve for the IC vessel is set to react slowly as the vessel has a long pressure | ||
+ | - The PID controls for each vessel are calibrated to maintain their respective setpoints to within +/- 0.1 Torr. If the operator notices a larger variation after an hour of PID control, notify the Rare Isotope Operations Vacuum Group. | ||
+ | |||
+ | ===== Zeroing PTs ===== | ||
+ | |||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | * The relevant PVs are "ZERO_CMD" | ||
+ | |||
+ | ====== Opening/ | ||
+ | |||
+ | Instructions on how to open/close the focal-plane chamber are described below. | ||
===== Open focal-plane chamber ===== | ===== Open focal-plane chamber ===== | ||
Line 18: | Line 100: | ||
* Turn on the switch to activate the motor opening the chamber. It takes about 10 minutes to get the chamber totally opened {{: | * Turn on the switch to activate the motor opening the chamber. It takes about 10 minutes to get the chamber totally opened {{: | ||
+ | ===== Closing focal-plane chamber ===== | ||
+ | * Turn the switch to move the chamber to position " | ||
+ | * 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 misconnected. | ||
- | ===== Installing FP scintillator ===== | + | ====== Installing FP scintillator ====== |
+ | |||
+ | Instructions on how to install the focal-plane scintillator are described below. | ||
* The figure below shows the FP chamber open, with the " | * The figure below shows the FP chamber open, with the " | ||
* 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 {{: | * 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 {{: | ||
- | * Using an allen wrench, unscrew the two bolts attaching the scintillator frame to the base of the chamber {{: | + | * Using an allen wrench, unscrew the two bolts attaching the scintillator frame to the base of the chamber {{: |
- | * Climb to the chamber and pull the scintillator frame up. Once unplugged, handle it to a second person {{: | + | * Climb to the chamber and pull the scintillator frame up. Once unplugged, handle it to a second person {{: |
- | * 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 | + | * 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 | + | * Connect the bases of the up and down phototubes. The latter |
* Using a plastic tie, attach the cable of the up phototube to the scintillator frame | * 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 " | ||
- | * When the chamber is almost close, turn the know to close the clamps | ||
- | * 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 (see above) is in place (closed). | ||
- | * In order to pumpdown the chamber, make sure that the manual vent valve is closed. Start manual pump to get a pressure below 50 mtorr {{: | ||
- | * Close the manual pump; open PanelMate **S800vac** and go to page 07. Select window **PUMPDOWN STATUS** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display " | ||
- | * Wait for some hours until vacuum is good |