【摘要】 介绍了中国原子能科学研究院Ｌ波段高亮度注入器中两种模式的行波聚束器的设计和调配，指出了少腔聚束器的研制特点，并给出了这两种聚束器应用在高亮度注入器中的效果更多还原

【Abstract】 n order to satisfied the requirement of free electron laser research with RF linac, China Institute of Atomic Energy has developed a L-band high current injector, it comprises a pulsed thermionic cathode gun, a standing wave cavity prebuncher at the twelfth subharmonic (108 MHz)of the accelerator frequency (1300MHz) and a fundamental frequency, traveling wave(TW), tapered phase velocity buncher for sabhamonic bunching theorem to produce a beam brightness of 10 9 A/(m·rad) 2. This paper will give the buncher research with a few cavities of two kinds of modes for L-band high current injector. For a few cavities of L-band buncher the phase velocity in the buncher is lifted quickly from the velocity of the electron gun to light vilocity, the shunt impedance of the buncher is changed quickly too, so it is difficult to tune the coupler of the buncher, the structure of the buncher is shown in Fig.1 and the parameters are shown in table 1 and 2, from that it can be seen the first several cavities are the bunching cavities , the second 3 cavities are the accelerating cavities with the phase felocity of β p =1, Because of the curve of VSWR of the buncher shown in Fig.2b in not periodic, so a replace method of tunning coupler is used for a few cavities buncher. Fig.3 is the schematic diagram of the coupler structure. In the first, an aluminium cavity core is used for tunning because of the budget. The trunning method is shown as follows, first, for the input coupler, an overcoupling is made in the coupler, then a diaphragm (in 6 of Fig.3)is used to reduce the coupling degrees, at the same time changing the nose cone of the coupler (in 1 of Fig.4) to change the frequency of the coupler, repeating it many tines until the optimum matching is get in the coupler at 1300MHz of the frequency, the same method is used to the output coupler, from the scanning oscilloscope, it is clear to see the curve of the VSWR of the couplers. Second, the aluminium cavity core of the input and output couplers will be changed by copper cavity cores of under coupling, and the diaphragm of the core will be enlared gradually until the optimum matching of the couplers will be get. Fig.5 is the characteristic curve of the VSWR of 1.8MHz of the frequency width under 1.2 of VSWR will be get in the L-band buncher. After the buncher being mounted in the L band high current injector, 3.4 ×10 9 A/(m·rad) 2 of the brightness will be get. compared with the two kinds of buncher (2π/3 mode or 3π/4 mode), it is find that the 2π/3 mode buncher is better than 3π/4 mode buncher (see Table 1 and Table 2).更多还原