Simulation of electron beam energy fluctuation in a linac: filtering of the utility parameterʹs information by ensemble average

Beam energy fluctuation in the linear accelerator (linac) is modeled for its stochastic factor and its determinate factor. Here, the stochastic factor means the noise in the RF component, and the determinate factor signifies only the utility parameters (the electric power supply, the temperature of the coolant water, and the room temperature). We demonstrate that the utility parameterʹs information buried in the stochastic factor appears in the N-units ensemble average. The results of the calculation using this model agree very well with the measurement data of the beam energy fluctuation.