TUPM8Y01
IMP/CAS, Lanzhou, People's Republic of China
The Chinese ADS Injector II has commissioned CW proton beam to 4.6 MeV, 3.9 mA with superconducting linac. Lessons of high-power beam commissioning, including lattice settings, phase scan, power ramping procedure and accidents will be presented.
THPM1Y01
IMP/CAS, Lanzhou, People's Republic of China
Chinese government has approved the CIADS project, which aims to demonstrate the nuclear waste transmutation technology. The CIADS driver accelerator is designed to be a 600MeV, 10mA CW operation superconducting linac. The main issue of such high power large-scale facility is the construction cost and beam loss control. For superconducting linac, the main cost is spent on the superconducting cavity and RF amplifier system. The improvement of acceleration efficiency of cavity and utilization of RF amplifiers will be useful for the cost saving. The other beam physics issues including lattice design, error simulation and adapted compensation strategy are also studied. In the talk, the cost optimization as well as beam physics considerations will be presented.
THPM2Y01
IMP/CAS, Lanzhou, People's Republic of China
The frequency detuning as large as 10 kHz observed on the RFQ of the Injector II of the CIADS when the beam passed by couldn’t be explained by the beam loading theory based on the equivalent circuit analysis, which is a mainstream theory being widely used in the analysis of beam loading nowadays. By introducing the concept of beam-cavity system, together with the impedance model of the beam, the beam induced detuning of the beam-cavity system was proved to be amount to the optimum detuning of the cavity under the given beam condition in a very straightforward way and the problem was therefore converted to the calculation of the optimum detuning of the RFQ. With the introduction of the new notions of effective synchronous phase and RF phase, the existing beam loading theory is extended to the analysis of the more complex accelerating structures, such as RFQ, which has many accelerating cells and with different synchronous phase in each cell, along with more than one dominant mode coexisting in the cavity. The numerical result obtained from the extended beam loading theory was well agreed with the experiment result mentioned at the beginning.