THE UPGRADING OF HLS LINAC MODULATORS

The existing five klystron modulators of HLS 200 MeV Linac use 50Hz high voltage power supplies and adopt resonant charging scheme with De-Qing circuit. The stability of the output high voltage is not satisfactory especially when the AC line voltage fluctuations. The control of the modulators is old manual method. In order to increase the stability, operating reliability and comply with the EPICS based new control system of HLS, a upgrading project is now in progress. The project includes two major parts. One is the replacing of old HV powers with five EMI 40kV constant-current charging powers. The other is the addition of PLC in each modulator as local controller.