Cavities are devices that accelerate beam, the AC in LINAC, they do so by creating an electric field that oscillates sinusoidallly. The Two common measurements that we worry about for these cavities are the Amplitude and Phase. The Amplitude is a measure of how strong that electric field is at its peak, measured in MV/m, and the phase is an offset of the sine wave, you took high school math and probably understand it well enough based on that. The frequency of this sine wave is not something we really deal with, CERN's LHC runs at 400 MHz so hopefully we're somewhere around there.

Cavities all live in these big cryomodules that regulate their temperatures, there can be up to 8 cavities per cryomodule and as little as 4. Their baseline temperatures can vary, but generally this will be around 5K, using the Fast Thermometry Page we can monitor this temperature and set alarms for any reading exceeding a certain upward limit based on the normal baseline temperature. There are 44 cryomodules and like 300 cavities.

RF vs. Amplifier

Wobbles: The phase of any given cavity is given to “wobble” on occasion, this is a minor hitch in its ramping and de-ramping that MPS declares unsafe, latching us from running. Meanwhile, these wobbles are a lapse in balance that quickly returns, the cavity catches itself and by the time you notice anything it's already back to functioning normally. MPS is still unhappy though, so you would follow this guide on how to clear it!

Trips: Trips are like wobbles, but with a more serious underlying cause. Not to say all trips are disasters, but they are more serious and result in the RF turning itself off. Once you ensure that the cause fo the trip isn't one of the issues in red here, you are free to follow this guide on restoring beam!

Front End

LS1

LS2

LS3