RFQ Manual, version 1.0 (E. Mané)

Also,this link shows a general beam line diagram, which is very useful for understanding how the RFQ connects with the rest of the system.

Step 0

• Logging into the TITAN-EPICS Main Menu page
  • On Linux
    • Open a terminal and type in "ssh -X titan@isacepics1.triumf.ca". Password required.
  • On Windows
    • Use for instance, x-win32. Double click on Sessions -> My Sessions -> "TitanEpics." Password required. Click "launch".

Step 1

• Start Ion source
  • Check vacuum on TITAN control
    • Go to Vacuum/Service on TITAN EPICS menu
    • Look at TIS1:IG1 -> Good vacuum < 10-7 torr.
  • Go to TRFC vacuum page
    • Open gate valve (TIS1:GV1)
    • Make sure RFQ section is OK
    • N.B. The action of switching the vacuum gauges on and off usually closes the interlocked valves for the vacuum section -> Never touch TIS1:IG1 on/off switch.
  • Go to Optics -> TRFCOptics1
    • Check that TRFC:BIAS is 0
    • Switch TRFQ/IS supplies on (TRFC: AC1A, AC1B, ACHV)
    • Set TRFC:FIL0 to 1000 mA
    • Switch all the remaining electrodes on
    • Put 15 V on YCB3N/YCB3S to avoid interlock issues with EPICS controls.
    • Set TRFC:BIAS to 20 kV (Start with 1 kV and increase voltage in steps of 1 kV).
    • Click on TRFC:BIAS -> RST PIS, and switch it ON (yellow color is normal)
    • Increase ion source current (TIS1:FIL0) to 2000 mA.
    • Ramp source to 2400 mA.
    • Put values of electrodes back to set values (numbers in blue on the right)
    • To start from scracth :
      • Go to main menu -> Save/Restore/Scale
      • Click on "Select tune File"
      • Open a recent file
      • Click on "View tune snap", and use values from the file. It's best to type in manually.
    • For now, in order to optimize, use all controls, apart from YCB1, XCB1 and YCB3.
    • N.B. The closest Faraday cup that measures the current from the ion source and before the RFQ is FC3.

  Step 2

  • Start RFQ
    • On TRFC Optics page, click on TRFC:RFQ (This will open the RFQ page). Alternatively you can go to Main Menu => RFSystems:RFQ
    • To switch DC electrodes, go to Save/Restore/Scale
      • Click on "Restore" -> Select tune file
      • Make sure RFQ section is OK
      • For forward extraction:
        Use file 090923-1019_RFQ-forward-extraction.snap
      • For reverse extraction:
        Use file 0904004-133_RFQ-reverse-extract.snap
      • Click on "View tune snap"
      • Click on "Restore tune"
      • Switch TRFC:TRFQ22/24 manually
      • N.B.1 Electrodes RFQ3 and RFQ2 are actually "on" despite the black color on EPICS. The readback value is so low that EPICS thinks it is "off".
      • N.B.2 Electrode TRFC:RFQ1 is connected to ground. The power supply for TRFC:RFQ1 is connected to TRFC:RFQ24 electrode (+).
      • Make sure that the Fwd/Rvs triggers are off.
      • Go to Main Menu/RF Systems/RF Generator
        Very Important: Make sure everything is "off", because if we inject gas when the RF is "on" it will damage the RF circuit.
    • To inject gas
      • Main Menu => Vacuum/Service/TRFC Vacuum
      • Open gate valves TRFC:IV0 and TRFCBL: IV0
      • Go to TIS1 Vacuum1 page
        • To activate the gas flow, open together
          • TRFC:FG1
          • TRFC:FG1:INV (No name on EPICS page)
          • TRFC:FG1:OUTV (No name on EPICS page)
        • Go to TRFC:FG1 and put 1 sccm.
    • To switch on the RF
      • Go to RFSystems on Main Menu and click on "RF Generator"
      • The procedure to switch the RF on is to go clockwise:
        • Start with PSD. PSD needs to be set at 230 V. Always
        • Switch on "Frequency Output Enabled".
        • Switch on "RF DC".
      • Likewise, the procedure to switch the RF off is to go anti-clockwise:
      • In order to find the RF and amplitude for each mass - > Click here

  Step 3

  • Get the system ready to operate in DC mode up to FC3 @ 20 kV
    • Go to "RFSystems" -> "RFQ" on main menu:
      • Change TRFC:RFQ1 to "-7" V.
    • Go to: "Main Menu" -> "RFSystems" -> "RFQ" -> "FW Trigger Setup"
      • Make sure all triggers are off.
    • Go to "Main Menu" -> "Optics" -> "TRF Optics 1"
      • Set TRFC:EL5 to "-10000" V.
      • Set TRFC:PB5 to "11125" V, for 20 kV extraction.
    • Bringing the section after FC3 up:
      • Type in the set values for Q1, Q2, Q3.
      • Put FC0 in and set it into autorange.
      • Put FC3 and FC0 together in the Strip tool.
    • Keep tuning until a reasonable transmission is achieved
  • Get the system ready to operate in AC (bunched) mode @ 20 kV.
    • Extraction in forward direction.
      • Forward trigger manual Rev. 0.0
      • Forward trigger manual Rev. 0.1
      • Pulse Drift Tube switch diagram
      • Go to "Main Menu" -> "RFSystems" -> "RFQ"
        • "090923-1019_RFQ-forward-extraction.snap" should be loaded.
        • Set TRFC:RFQ1 to "+5" V.
      • Go to "Main Menu" -> "Optics" -> "TRFC Optics 1"
        • Set TRFC:EL5 to "-3200" V.
        • Set TRFC:PB5 to "18000" V.
        • Very important: Never apply more than 20 kV on PB5. This will damage the HV switch.
      • Open all gate valves.
      • Go to "Main Menu" -> "RFSystems" -> "RFQ" -> "FW Trigger Setup"
        • Extraction enabled on.
        • N.B. Make sure that the "Fibre Output Inversion" -> "Invert tube trigger" is on for forward extraction.
    • Extraction in reverse direction
      • For general reference on the VME module used for reverse extraction :
        • Reverse trigger manual Rev. 0.0
        • RVS extraction ppg timing cycle
        • N.B. The YCB3N and YCB3S outputs need to be exchanged from the forward extraction VME module to the reverse extraction module.
      • Go to "Main Menu" -> "RFSystems" -> "RFQ"
        • "0904004-133_RFQ-reverse-extract.snap" should be loaded.
        • Set TRFC:RFQ1 to "+5" V.
      • Open all gate valves in the polarizer section.
      • Go to "Main Menu" -> "RFSystems" -> "RFQ" -> "Rvs Trigger Setup"
        • Extraction enabled on.

  Step 4

  • Getting the beam upstairs around the bend.
    • Go to "TRF Beam line" under "Main Menu" -> "Optics"
    • Also open "TSYBL Optics".
      • Under this page, go to "EBIT-MPET". Make sure TSYBL:CCB4 is on
      • N.B. To send beam straight to MPET, go to "RFQ-MPET" page. Make sure the electrodes below are set to 0 V:
        • TSYBL:XCB0L
        • TSYBL:B1
        • TSYBL:B8
        • TSYBL:XCB8L
    • Type in the set values for the elements around the bend.

  Step 5

  • Using YCB3N and YCB3S as beamgates
    • ISAC beam gate with IL2T:YCB3N &. IL2T:YCB3S

  Troubleshooting

  • Procedure for opening HV cage:
    • Check that RF is switched off.
    • Check that buffer gas valves are closed.
    • Put Faraday cups FC3 and FC0 in.
    • Slowly ramp down Pulse Drift Tube electrode PB5
    • Slowly ramp down Einzel lens EL5
    • N.B. If the RFQ HV cage needs to accessed, as well as the RFQ itself, then the ion source needs to be switched off.
      • In this case, FIL0 needs to be slowly ramped down to "0"
    • TRFC:BIAS should be ramped down slowly. (Steps off 1000 V is fine).
    • Switch off :
      • TRFC:AC1A
      • TRFC:AC1B
      • TRFC:AC1H
    • To open the cage, use the keys according to the numbers provided in the transfer boxes.
    • Once the RFQ cage is opened
      • Check that all 5 green leds (+15V,-15V,+24V,-48V) on Canbus 24V module are on.
        • N.B. The -48V led usually goes off after a HV spark, or if the power of the whole rack goes off.
      • If any of the leds is off, pull DC16, DC24 connectors and plug them back.
  • Reports on the RF electronics for the RFQ
    • Capacitance of TITAN RFQ driver and RFQ structure, extraction electrode considerations, and power dissipation in the driver
    • Development of a high-voltage 3 MHz RF-DC coupling board
    • Implementation of the Electronics for a Radio Frequency Quadrupole
    • Recommendations
  • Procedure to change ion source
  • Procedure to change gas bottle