A brief introduction to the software used to run up SRF cavities
Full source code can be found here. It can be run natively on unix systems using the Local PyDM/Simulacrum Setup instructions
Overview
The need for automation arose from the human error involved in manually implementing a long list of clearly defined steps.
The basic procedure is:
- Run an SSA calibration
- Tune a cavity to resonance (a detune of 0Hz)
- Characterize the cavity and calculate the probe Q
- Ramp the RF to the desired amplitude (ADES)
SSA Calibration
Using a previously saved drive max found during initial cryomodule commissioning as a starting point (or 1 for the harmonic linearizers), it recursively runs an SSA calibration with decreasing drive max until either the calibration succeeds or it hits one of two fault conditions:
- The max forward power is less than 3kW
- The desired drive max is less than 0.5