Linac Klystron three (K3) supports the operation of our PCGun and Injector Test Stand. It also is our backup klystron for K1 and K2 in the event they become disabled. With that said, it is important that K3 and related waveguide, windows and s-band switches remain in a RF conditioned state. This K3 RF Conditioning Guide has been created for that purpose. In the event K2 fails K3 will need to provide a minimum of 28MWatts of klystron power to the L2 SLED in support of User Operations.
This conditioning guide will be utilized every other week when not supporting PCGun Operations, Injector Test Stand experiments or during the Injector Studies Period.
Please read the following K3 conditioning outline before starting!
Operators Guide to Conditioning -
Verify L3 is directed to the water load, Mode 0_K3_Down.
Verify L3 "RF Gate Start" is at -4.2 µs and "RF Gate width" is at 4.5 µs.
Start out with L3 PFN voltage at 28 kV with a forward power of 10 MW.
Now start increasing the klystron (forward) power by 0.2 to 0.3 MW steps every 10 to 15 minutes by adding drive power.
At some point the klystron will reach saturation, (meaning adding drive power will not affect klystron output power level any more), or the drive power level is close to 200 W. To increase the L3 power range, first lower the klystron drive power to about 150 W. Start increasing the L3 modulator PFN voltage in 0.1 kV (one click) steps every 10 to 15 minutes. Continue until 28MW is reached. Hold at 28 MW for ~2 hours then return modulator PFN to 28 kV followed by adjusting the klystron drive power until 10 MW klystron forward power is indicated.
Always monitor L3 vacuum strip charts when making changes to the klystron forward power. If more than two vacuum spikes are present with in the window and/or vacuum spikes reach 1e-6 range, vacuum is active (the system is outgassing), and you should slow down and wait few a minutes before resuming conditioning.
In case of a vacuum or VSWR trip, lower klystron drive power (increase "Attn Ctrl" voltage by 0.5 V) or lower the modulator PFN voltage by 1 kV, wait until vacuum becomes better than 1e-7, reset the trip and continue conditioning.
In case of a "Arc detector" trip, increase "Attn Ctrl" by 1.0 V or lower PFN voltage by 3 kV, reset trip and try to gradually restore to the previous power level. If "Arc detector" trip occurs a second time, reset trip as directed above but return the L3 to a normal operating PFN value of 28 kV with a forward power of ~10 MW.
Log all trips and any abnormal behavior in the Logbook.
Contact the EIC in the event of any additional rf conditioning questions or unusual events. Contact the Linac CO for any operational linac questions.