4 research outputs found
Recommended from our members
Constant-current charging supplies for the Advanced Photon Source (APS) linear accelerator modulators
The APS linac beam energy must be stable to within {+-}1% to match the energy acceptance of the positron accumulator ring. The klystron pulse modulators must therefore provide a pulse-to-pulse repeatability of 0.1% in order for the beam to have the required energy stability. The modulators have had difficulty achieving the necessary repeatability since the pulse forming network (PFN) charging scheme does not include a deQing circuit. Several of the major charging circuit components are also less reliable than desired. In order to increase operating reliability and to improve pulse-to-pulse stability, it is planned to replace the high voltage power supplies in all modulators with constant-current power supplies. A new modulator charging supply that contains two EMI series 303 constant-current power supplies was constructed. Each of these EMI supplies delivers 1.5 A at up to 40 kV. One supply is sufficient for linac operation at up to 45 Hz, and two supplies in parallel enable linac operation at the nominal rf repetition rate of 60 Hz. This paper discusses test results from the new modulator, and also describes the existing modulators and their performance limitations
Recommended from our members
Phase control and intra-pulse phase compensation of the Advanced Photon Source (APS) linear accelerator
Rf power for the APS linear accelerator is provided by five klystrons, each of which feeds one linac ``sector,`` containing accelerating structures and SLED cavities. A VXI-based subsystem measures the phase of each sector of the linac with respect to a thermally stabilized reference line. The resulting information is used to control a linearized varactor phase shifter. Error correction is done by software, using operator-controllable parameters. A second phase shifter provides an intra-pulse correction to the phase of the klystron drive pulse. When the intra-pulse correction is applied, the resulting phase is flat to within 0.5{degrees} after 2.5 {mu}sec. A second correction, made after the PSK trigger to the SLED and during the filling of the accelerating structures, resulted in an energy gain of 5 MeV from a single sector
Recommended from our members
A VXI-based, integrated system of beam position monitoring and rf measuremednt for the Advanced Photon Source (APS) linear accelerator
A combined system of beam position monitoring and rf measurement has been implemented at the APS S-band linear accelerator (linac). The linac is subdivided into five sectors and each sector is comprised of a klystron and associated accelerating structures. The instrumentation for each sector is located, together with its processor, in two VM mainframes. This system has operated successfully for more than a year
Recommended from our members
Bunch length measurements at the Advanced Photon Source (APS) linear accelerator
Measurements of the APS linac micro-bunch length are performed by backphasing a single 2856-MHz, S-band linac waveguide and using a downstream spectrometer to observe the beam. By measuring the beam width in the dispersive plane as a function of rf power into the linac waveguide, the bunch length can be determined absolutely provided the beam energy and dispersion at the spectrometer are known. The bunch length determined in this fashion is used to calibrate a fifth-harmonic bunch length cavity which is used for real-time bunch length monitoring