FLARE cathode conditioning

See the RI FLARE LINAC Manual, and also the PPT Manual Electron Source for background and safety steps.

Steps:

• At FLARE HV deck
  • disconnect and ground the HV capacitor

• At FLARE console
  • Take RSS to RUN level

• At the high voltage power supply (FTA, top level, all the way in the back)
  • Set the current and voltage both to zero
  • Set the mode to local
  • Turn the key to conditioning mode

• At the FLARE console
  • release the BEAM interlock
  • in the Beam optics and Vacuum program, check that you are Master, and enable the reset button

• VNC to linac-control
  • turn on high voltage power supply

• At the high voltage power supply:
  • set voltage to 100 kV
  • slowly increase current until HV trips (sparks)
    • reset e-source error and wait until power supply turns on again
  • wait until no more trips occur for a given current
  • keep increasing current slowly when the HV has become stable
  • for instance, 1 µA, 2 µA, 4 µA, 10 µA, 20 µA, 40µA, 70 µA, 100 µA, 130 µA, 160 µA etc.
  • At (at 100 kV), the power supply will switch from CC to CV, and conditioning is complete.
    • On the cathode installed in Feb. 2019, this required around 800 µA of current.
  • switch the key back from conditioning to normal mode

• • (optionally:) On linac-control, run Autohotkey script to keep pressing shift-f4 (will reset e-source error) on the "e-source HMI" to automate cycle. Otherwise you will be spending a lot of time in the FTA pressing the reset button over and over again. Do keep an eye on the process if you decide to go this way.

• At the FLARE HV Deck
  • unground the capacitor and reconnect to HV deck.

References

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Free-electron Laser for Advanced spectroscopy and high-Resolution Experiments

Linear particle accelerator - an accelerator in which particles travel in straight lines, not in closed orbits

Radiation Safety System