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installation_fp_sci [2023/02/17 20:16] pereira [Pumpdown of FP Chamber] |
installation_fp_sci [2023/07/12 08:43] noji |
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Instructions on how to vent/ | Instructions on how to vent/ | ||
- | ===== Emptying | + | ===== Emptying Detectors ===== |
- Check that the system is in **RUN** mode on the “FP_State_Buttons” page under FRIB EXP Main → S800 → GHS Pages (Secondary Pages) | - Check that the system is in **RUN** mode on the “FP_State_Buttons” page under FRIB EXP Main → S800 → GHS Pages (Secondary Pages) | ||
- Return to “GHS_FP_Main” click **Enable MFC Controls** | - Return to “GHS_FP_Main” click **Enable MFC Controls** | ||
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- 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. | - 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. | - 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: | + | - 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 |
- | - Open a data browser and plot the PVs for PT1 and PT2. | + | - Open a data browser and plot the PVs for PT1 (S800_GHS: |
- Wait for PT1 and PT2 to read < 2 Torr. This should take about 30 minutes. | - Wait for PT1 and PT2 to read < 2 Torr. This should take about 30 minutes. | ||
+ | - Open the Focal Plane VAC D2686 page (FRIB EXP Main → S800 → Vacuum Main → Focal Plane). | ||
+ | - Ensure the beamline gate valve to the FP chamber is closed (BGV_D2671). | ||
+ | - Ensure IG_D2686 is off. | ||
+ | - 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 ===== | ===== 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. | - 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**. | + | - Check the box next to “Valve Controls”, |
- | - 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. | + | - Turn the TMP off. |
- | - Once the FPG bottoms out, check the box next to “Valve Controls”, | + | - Ensure both CRDCs and IC are in *VENT* mode |
- | - If the system will only be vented for a short time, leave the TMP on, otherwise turn it off. | + | - Plot PT1 (S800_GHS: |
- | - 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 (~1 second) open the vent valve by clicking **Open** next to the valve labeled “Vent” then click **Close**. Check that all the pressures are increasing at the same rate. |
- | - Briefly (~2 seconds) open the vent valve by clicking **Open** next to the valve labeled “Vent” then click **Close**. Check that all the pressures are increasing at the same rate. | + | - Again, open the vent valve and observe the pressure for 30 seconds to ensure the pressures are increasing at the same rate among all four gauges. If a difference of > 2 Torr is observed between any two gauges, click **Close** on the vent valve. |
- | - Again, open the vent valve and observe the pressure for 30 seconds to ensure the pressures are increasing at the same rate among all four gauges. If a difference of > 1 Torr is observed between any two gauges, click **Close** on the vent valve. | + | - Allow the pressure to rise to ~735 Torr (~45 min). The vent valve __should__ close itself at 735 Torr but be ready to close it manually if an error occurs. |
- | - Allow the pressure to rise to ~735 Torr over the next hour. The vent valve __should__ close itself at 735 Torr but be ready to close it manually if an error occurs. | + | |
The CRDC (Purple) and IC (Green) vessel pressures during Emptying and Venting procedures outlined above are shown below. | The CRDC (Purple) and IC (Green) vessel pressures during Emptying and Venting procedures outlined above are shown below. | ||
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- Open “Focal Plane Pumping Station” page from FRIB EXP Main → S800 → Vacuum Main (Primary Pages). | - 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). | - Open “GHS_FP_Main” and “FP_State_Buttons” pages from FRIB EXP Main → S800 → GHS Pages (Secondary Pages). | ||
- | - 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. | + | - Plot PT1 (S800_GHS: |
- | - On the “FP_State_Buttons” page change from “Vent” mode to “Pump” mode by clicking **PUMP** in both the D2703 and D2708 tabs. | + | - On the “FP_State_Buttons” page change from “Vent” mode to “Pump” mode by clicking **PUMP** in both the D2703 (CRDC) |
- | - Check the box next to “Valve Controls” on the “D2686 | + | - Check the box next to “Valve Controls” on the “Focal Plane VAC D2686” page. |
- | - If 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 rouging | + | - Ensure |
- | - If the TMP is still on (this could be the case for a short vent period), turn it off and close the foreline valve (FV) before doing step 6. | + | - When the BPG reads < 300 mTorr, **Close** RV and **Open** FV. Turn the TMP on. When the TMP is “at speed”, **Open** the TGV. |
- | - When the BPG reads below 200 mTorr, **Close** RV and **Open** FV. Turn the TMP on if it is not already. When the TMP is “at speed” **Open** the TGV. | + | - Once the BPG reads < 5 mTorr, the IG may be turned |
- | - NOTE: before reach "at speed", | + | |
- | - If the TMP was off before opening the TGV, the chamber pressure | + | |
- | - Allow the TMP to pump on the system until the IG reads < 1E-5 Torr. | + | |
- | - On the “FP_State_Buttons” page click **RUN** to enter run mode. | + | |
- | ===== Filling & Running | + | ===== Filling & Running Detectors ===== |
- | - Plot PT1, PT2, and the control valves for both D2703 (CRDC) and D2708 (IC). | + | |
+ | - On the “FP_State_Buttons” page click **RUN** on both D2703 (CRDC) and D2708 (Ion Chamber) tabs. | ||
+ | | ||
- 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. | - 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: | - If the CRDC valve remains completely open (stuck at 100%), open a probe with PV: “S800_GHS: | ||
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- 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. | - 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. | - 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. | ||
+ | - 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 in order to equalize the pressure around the setpoint. Note that the CRDC pressure will change much faster than the IC pressure and has a much smaller tolerance. If PT2 reaches **45 Torr** the system will immediately enter “EMPTY” mode to prevent the foil disc from bursting. Use the figure below for reference. {{: | - As the vessels approach their setpoints the Control Valves should begin to increase from their BASE values in order to equalize the pressure around the setpoint. Note that the CRDC pressure will change much faster than the IC pressure and has a much smaller tolerance. If PT2 reaches **45 Torr** the system will immediately enter “EMPTY” mode to prevent the foil disc from bursting. Use the figure below for reference. {{: | ||
- | - If PT2 reaches **44 Torr** and the control valve is not open enough to start decreasing the pressure, immediately set MFC2 to 0 sccm and allow the valve to begin decreasing the pressure before resetting MFC2 back to 8 sccm. Notify | + | - If PT2 reaches **44 Torr** and the control valve is not open enough to start decreasing the pressure, immediately set MFC2 to 0 sccm and allow the valve to begin decreasing the pressure before resetting MFC2 back to 8 sccm. Notify |
- | - 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 equilibriate | + | - 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 |
- | - The control valve for the IC vessel is set to react slowly as the vessel has a long pressure period. The valve will not “wake up” until 300 Torr is reached on PT1. This is okay as long as the control valve begins to open by this point. The pressure change is slow enough that over the next hour the valve will open enough to catch the pressure before it exceeds 305 Torr, well within the operating limit (500 Torr). | + | - If CSET is not set to **300 Torr**, adjust MFC1 back to 25 sccm when the setpoint is reached. |
- | - 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 control valve for the IC vessel is set to react slowly as the vessel has a long pressure period. The valve will not “wake up” until 300 Torr is reached on PT1. This is okay as long as the control valve begins to open by this point. The pressure change is slow enough that over the next hour the valve will open enough to catch the pressure before it exceeds |
+ | - 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 | ||
====== Opening/ | ====== Opening/ | ||
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* Turn the knob to close the clamps | * Turn the knob to close the clamps | ||
* Inspect the clamps and chamber flange (no gaps) to ensure that the chamber is properly sealed | * 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 | + | * 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 |
====== Installing FP scintillator ====== | ====== Installing FP scintillator ====== | ||
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* 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 | ||