The HLS-II injector is composed of a linear electron accelerator working with traveling wave mode and beam transfer line. The electron source is a traditional DC gun with a thermal cathode. The outgoing electron beam from the gun has a macro pulse length of 1 ns and bunch charge of 1.5 – 2.2 nc. After going through a pre-buncher and buncher, the micro pulse length of the electron beam turns into 10 ps. After traversing the accelerating structures, the electron beam is accelerated to 800 MeV. A switch magnet is installed at the end of the linac. Using this magnet, the electron beam, as required, can be delivered to the energy spectrum analysis system, to the transport line for the injection of the storage ring, or for other uses.
Main parameters of the HLS-II linac
Beam energy | 800 MeV |
Macro pulse | 1 ns |
Micro pulse | 10 ps |
Bunch charge | 1 nC |
Energy spread (rms) | 0.5% |
Energy stability (rms) | 0.5% |
Horizontal emittance (norm.) | <60π mm•mrad |
Vertical emittance (norm.) | <60π mm•mrad |
Repetition rate | 1 Hz |
RF frequency | 2856 MHz |