Measurement of beam loading at the SNS superconducting linac for a beam with β<1

A 10 MeV RF linac for industrial applications

“…So when the linac is operated at 250 mA, δω = tan ψ 2Q T × ω 0 = 212 kHz. The resonant frequency shifts to a lower frequency when the stable phase of the electron bunch is ahead of the field crest [10][11][12][13].…”