Preliminary study on the RF tuning of CSNS DTL

In the R&D of the CSNS Drift Tube Linac (DTL), the first unit tank with 28 drift tubes has been developed. The axial accelerating field is ramped from 2.2 MV/m to 3.1 MV/m in this tank. The required field flatness is less than +/- 2% with the standard deviation of 1% for the beam dynamics; the field stability should be less than 1% for machine stable operation. After successful alignment, RF tuning was carried out focusing on the field profile measurement. Four slug tuners and eleven post couplers were applied in this procedure. The ramped field and required stability had been achieved by fine adjustment of the slug tuners and post couplers. In this paper, the preliminary tuning results are presented and discussed.