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installation_fp_sci [2019/07/01 09:02] pereira [Vent focal-plane chamber] |
installation_fp_sci [2023/02/17 20:09] pereira [Venting FP Chamber] |
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- | 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. | + | //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/ | + | 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. |
- | ===== Vent focal-plane chamber | + | |
- | | + | {{: |
- | * Open the [[gas_handling_system# | + | |
- | | + | Instructions on how to vent/ |
- | * Ensure that the FP ion gauge (I264IG) is off (see details [[vacuum_control|here]]) | + | |
- | | + | ===== Emptying FP Gaseous Detectors |
- | | + | |
- | * Click on the **VENT STATUS** window | + | |
- | * Gently open the manual venting valve until the pressure displayed in the Pirani Gauge (see figure below) increases by ~1 torr every 15 seconds | + | - 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 |
- | * Wait until the chamber is vented (few hours). The **I261PG** Pirani Gauge should | + | - 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 (IC vessel) tab. Click **MAN** to enable manual mode. Click **OPN** for “S800_GHS: |
- | * When the chamber is fully vented, select | + | - Open a data browser and plot the PVs for PT1 and PT2. |
- | | + | - Wait for PT1 and PT2 to read < 2 Torr. This should take about 30 minutes. |
+ | |||
+ | ===== Venting FP Chamber | ||
+ | - Ensure the IG in the Focal Plane Pumping Station is off. This page can be found in FRIB EXP Main → S800 → Vacuum Main (Primary Pages) → Focal Plane. | ||
+ | - Return to the “FP_State_Buttons” page and for each of the D2708 and D2703 tabs click **PUMP**. | ||
+ | - Click **VENT** for each tab. This will expose the vessels to the Pumping Station. Observe the FPG on the “D2686 Pumping Station” page to ensure the Turbo Pump is not overloaded. | ||
+ | - Once the FPG bottoms out, check the box next to “Valve Controls”, | ||
+ | - If the system will only be vented for a short time, leave the TMP on, otherwise turn it off. | ||
+ | - Plot PT1, PT2, and PT3 from the “GHS_FP_Main” page as well as BPG from the “D2686 Pumping Station” page on the same axis. | ||
+ | - Briefly (~2 seconds) open the vent valve by clicking | ||
+ | | ||
+ | | ||
+ | |||
+ | 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 “Focal Plane Pumping Station” page from FRIB EXP Main → S800 → Vacuum Main (Primary Pages). | ||
+ | - Open “GHS_FP_Main” and “FP_State_Buttons” pages from FRIB EXP Main → S800 → GHS Pages (Secondary Pages). | ||
+ | | ||
+ | - On the “FP_State_Buttons” page change from “Vent” mode to “Pump” mode by clicking | ||
+ | - Check the box next to “Valve Controls” on the “D2686 Pumping Station” | ||
+ | | ||
+ | | ||
+ | - When the BPG reads zero, **Close** RV and **Open** FV. Turn the TMP on if it is not already. When the TMP is “at speed” | ||
+ | - Allow the TMP to pump on the system until the IG reads < 1E-5 Torr. | ||
+ | | ||
+ | |||
+ | ===== Filling & Running FP Gaseous Detectors ===== | ||
+ | |||
+ | - Plot PT1, PT2, and the control valves for both D2703 (CRDC) and D2708 (IC). | ||
+ | | ||
+ | - 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 | ||
+ | - 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 pressure. In order to fill the vessel in a timely manner it is safe to override the MFC and set it to “Fully Open”. To do this select “Fully Open MFC” in the dropdown menu next to MFC1. | ||
+ | - If desired, the CRDC vessel can be filled with MFC2 set to 16 sccm. Be ready to decrease MFC2 back to 8 sccm at **35 Torr** as the PID controls are not calibrated to prevent the vessel from overpressurizing at this increased flow. Allow the CRDC vessel to slowly approach 40 Torr. | ||
+ | | ||
+ | | ||
+ | - Once PT1 reaches | ||
+ | | ||
+ | - 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 Brandon Ewert. | ||
+ | |||
+ | ====== Opening/ | ||
+ | |||
+ | Instructions on how to open/close the focal-plane chamber are described below. | ||
===== Open focal-plane chamber ===== | ===== Open focal-plane chamber ===== | ||
Line 26: | Line 74: | ||
* 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 miss connected | ||
- | ===== 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 " | ||
Line 38: | Line 94: | ||
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- | ===== 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 miss connected | ||
- | |||
- | ===== Pumping focal-plane chamber ===== | ||
- | * 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) {{: | ||
- | * 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) | ||
- | * Select window **PUMPDOWN STATUS** and click on button **START PUMPDOWN**. The **PUMPDOWN STATUS** and **VENT STATUS** windows should display " | ||
- | * 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. | ||
- | * 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**. | ||
- | * Wait for few hours until vacuum is good. You can then turn on the ion gauge **I264IG** | ||
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