The invention provides a
drift tube linear accelerator on-line
frequency compensation method, which comprises the following steps: firstly, constructing an initial cavity three-
dimensional simulation model, judging the flatness of an
axial field through calculation, and adjusting the angle of an eccentric sheet if the flatness does not reach the standard; calculating the stability of the
electric field, and adjusting the length of the
coupling rod if the
electric field does not reach the standard; the field flatness is judged again after stability tuning, and the angle of the eccentric piece is adjusted if the field flatness does not reach the standard; a tuning block is added according to an opening of the cavity, wherein the tuning block comprises a new
pickup port
tuner, and a
vacuum pump mesh, a fixed
tuner and a rod coupler are improved; after a tuning block is added, frequency,
axial field flatness and stability calculation is carried out, if the three indexes all meet requirements, compensation is ended, and otherwise, it is considered that compensation cannot be carried out; according to the method, a
frequency compensation scheme can be simulated and determined, so that the field flatness and stability meet the operation requirements, and a
cold test system is prevented from being rebuilt in a tunnel for field adjustment.