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.

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.

Instructions on how to vent/pump-down the focal-plane chamber and empty/fill and run detectors are described below.

1. Check that the system is in RUN mode on the “FP_State_Buttons” page under FRIB EXP Main → S800 → GHS Pages (Secondary Pages)
2. Return to “GHS_FP_Main” click Enable MFC Controls
3. Set MFC1 to 0 sccm to stop the flow of P10 to the IC vessel
4. 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.
5. 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.
6. 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:SV_D2708:OPN_CMD_10” to open an additional valve to the pump.
7. Open a data browser and plot the PVs for PT1 and PT2.
8. Wait for PT1 and PT2 to read < 2 Torr. This should take about 30 minutes.

1. 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.
2. Return to the “FP_State_Buttons” page and for each of the D2708 and D2703 tabs click PUMP.
3. 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.
4. Once the FPG bottoms out, check the box next to “Valve Controls”, then click Close next to the Turbo Gate Valve (TGV).
5. If the system will only be vented for a short time, leave the TMP on, otherwise turn it off.
6. Plot PT1 (S800_GHS:CMG_D2708A:VP_RD), PT2 (S800_GHS:CMG_D2703A:VP_RD), and PT3 (S800_GHS:CMG_D2708C:VP_RD) from the “GHS_FP_Main” page as well as BPG (RBT_BTS34:BPG_D2686:VP_RD) from the “D2686 Pumping Station” page on the same axis.
7. 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.
8. 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.
9. 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.

1. Open “Focal Plane Pumping Station” page from FRIB EXP Main → S800 → Vacuum Main (Primary Pages).
2. Open “GHS_FP_Main” and “FP_State_Buttons” pages from FRIB EXP Main → S800 → GHS Pages (Secondary Pages).
3. Plot PT1 (S800_GHS:CMG_D2708A:VP_RD), PT2 (S800_GHS:CMG_D2703A:VP_RD), and PT3 (S800_GHS:CMG_D2708C:VP_RD) from the “GHS_FP_Main” page as well as BPG (RBT_BTS34:BPG_D2686:VP_RD) from the “D2686 Pumping Station” page on the same axis.
4. On the “FP_State_Buttons” page change from “Vent” mode to “Pump” mode by clicking PUMP in both the D2703 and D2708 tabs.
5. Check the box next to “Valve Controls” on the “D2686 Pumping Station” page.
6. 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 out the chambers.
7. 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.
8. 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” (~30,000 RPM), Open the TGV.
9. NOTE: before TMP reaches “at speed”, pressure in the chamber, as read by BPG, might increase to a point where TGV can not be open. If that is the case, turn off the turbo pump, close FV, and repeat steps 6, 7, 8 but this time, wait for BPG to read below 100 mTorr. Then try again step 8.
10. Allow the TMP to pump on the system until the IG reads < 1E-5 Torr.
11. On the “FP_State_Buttons” page click RUN to enter run mode.

1. Plot PT1, PT2, and the control valves for both D2703 (CRDC) and D2708 (IC).
2. 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.
3. If the CRDC valve remains completely open (stuck at 100%), open a probe with PV: “S800_GHS:CV_D2703:MODE_CSET_PVC”. In the “New Value” box, enter “CLOSE” and press enter. If the valve then closes (100% to 0%), enter “AUTO” in the “New Value” box and press enter. This should reenable PID control.
4. Click Enable MFC Controls.
5. Set MFC1 to 25 sccm. Ensure PT1 begins to increase in pressure.
6. Set MFC2 to 8 sccm. Ensure MFC3 automatically sets to 32 sccm and PT2 begins to increase in pressure.
7. 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.
8. 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.
9. 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.
10. 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 Brandon Ewert (ewert@frib.msu.edu). Continue to monitor the pressure and control valve behavior to ensure the PID is in control of the pressure.
11. 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 down to about 299.5 Torr. Allow the IC vessel to slowly approach 300 Torr. Use the figure below for reference.
12. 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).
13. 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.

Instructions on how to open/close the focal-plane chamber are described below.

• After venting the FP chamber, the pressure inside the chamber is slightly above atmospheric due to the dry N2 pumped. Before opening the chamber, it is recommended to vent the extra N2 by “forcing” the pressure-relief valve with e.g. a screwdriver
• Unlock the padlock protecting the power brakers of the switch controls to open the chamber, and press the START button
• Turn the switch to open the clamps holding the FP chamber. The weight held by the hydraulic piston will increase
• Turn on the switch to activate the motor opening the chamber. It takes about 10 minutes to get the chamber totally opened

• Turn the switch to move the chamber to position “UP”, and keep it that way for about 10 minutes (the time it takes the chamber to be closed)
• 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

Instructions on how to install the focal-plane scintillator are described below.

• The figure below shows the FP chamber open, with the “old” FP scintillator to be replaced by the new one
• 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
• 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
• Connect the bases of the up and down phototubes. The later is quite difficult because one cannot see the pins
• Using a plastic tie, attach the cable of the up phototube to the scintillator frame