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In the digital low level RF (LLRF) system of a circular (particle) accelerator, the RF field signal is usually down converted to a fixed intermediate frequency (IF). The ratio of IF and sampling frequency determines the processing required, and differs in various LLRF systems. It is generally desirable to design a universally compatible architecture for different IFs with no change to the sampling frequency and algorithm. A new RF detection method based on a double heterodyne architecture for wide IF range has been developed, which achieves the high accuracy requirement of modern LLRF. In this paper, the relation of IF and phase error is systematically analyzed for the first time and verified by experiments. The effects of temperature drift for 16 h IF detection are inhibited by the amplitude and phase calibrations. 相似文献
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设计并搭建了一套高精度的磁场测量和补偿系统,并结合中国科学院高能物理研究所(IHEP)的2K超导腔垂直测试平台对1.3 GHz单加速间隙超导腔的磁通排出效应开展了实验研究:利用研制的磁场测量和补偿系统能够精密地测量超导腔赤道位置磁场,并能够将磁场补偿至小于5.0×10-8 T;并对超导腔不同表面温度梯度下的磁通排出效应进行了测量分析;对钉扎了磁场的超导腔进行了射频性能测试,研究了超导腔电阻对磁通钉扎的敏感度,以及在不同电场梯度下超导腔的表面电阻变化情况。结果表明,研制的高精度磁场测量和补偿系统能够满足超导腔磁通排出研究的需求;高的超导腔表面温度梯度有利于磁通的排出;磁通钉扎电阻的敏感度随着加速电场梯度的增加而增大,导致超导腔的性能下降。此实验研究也为后续超导腔的研制奠定了一定基础。 相似文献
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为了大幅度提高纯铌超导腔的品质因数,从而降低其使用功耗,选择对超导腔进行高温氮掺杂处理。立足国内外大型加速器的需求,中国科学院高能物理研究所首先开展了1.3 GHz 1-cell超导腔的研究,包括常规处理以及氮掺杂实验,并且对掺杂前后的结果进行了分析、对比。结果表明,通过掺氮,两只1.3 GHz 1-cell细晶粒纯铌超导腔的品质因数均获得了显著提升,同时在超导腔低温垂直测试中观察到了比较明显的反常的品质因数随加速梯度变化的曲线,即"anti-Q-slope"现象。 相似文献
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Design study on very low Beta spoke cavityfor China-ADS 总被引:1,自引:0,他引:1
Very low Beta superconducting spoke cavity is one of the key challenges for the China-ADS project. In this paper, a new structure of 3βλ/2 spoke cavity is first studied in detail. Its RF and mechanical properties are simulated using CST-MWS and ANSYS, and compared with the traditional βλ/2 spoke structure. 相似文献
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Peking University is developing a 1.3 GHz superconducting accelerating section highpower THz freeelectron laser for the China Academy of Engineering Physics(CAEP). A compact fast/slow tuner has been developed by the Institute of High Energy Physics(IHEP) for the accelerating section to control Lorentz detuning, compensate for beam loading effect, microphonics and liquid helium pressure fluctuations. The tuner design, warm test and cold test of the first prototype are presented, which has a guiding significance for the manufacture of the formal tuner and cryomodule assembly. 相似文献
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A spoke cavity is a TEM-class superconducting resonator with particular advantages: compact structure and high shunt impedance. The 325 MHz β =0.40(β =v/c, v is the velocity of particle and c is the velocity of light)single spoke cavity(Spoke 040) is adopted for the Chinese ADS(Accelerator Driven Sub-critical System) project. The physics and mechanical design has been accomplished, and the fabrication of a prototype is currently in progress. In this paper, the optimization processes for the main radio frequency(RF) and mechanical parameters are analyzed in detail. Two kinds of cavity end-walls(flat and convex) are compared. The convex end-wall is preferred in order to improve mechanical performance of the cavity. Two prototypes of the Spoke 040 cavity are in the machining stage,and should be finished in early 2014.Vertical testing is also under preparation. 相似文献
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Twelve very low Beta superconducting single spoke cavities, whose Beta is only 0.12 (Spoke012) when operating at 325 MHz, are adopted in Injector I for China-ADS linac. This type of spoke cavity is believed to be one of the key challenges for its very low geometric Beta. So far, in collaboration with Peking University and Harbin Institute of Technology, IHEP has successfully designed, fabricated, and tested the Spoke012 prototype cavity. This paper presents the details of the design, fabrication and test results for Spoke012 prototype cavity. 相似文献
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A flexible high power RF test stand has been designed and constructed at IHEP to test a variety of 500 MHz superconducting RF components for the upgrade project of the Beijing Electron Positron Collider (BEPCⅡ), such as the input coupler, the higher order modes (HOMs) absorber and so on. A high power input coupler has been conditioned and tested with the RF power up to 250 kW in continuous wave (CW), traveling wave (TW) mode and 150 kW CW in standing wave (SW) mode. A prototype of the HOMs absorber has been tested to absorb power of 4.4 kW. An introduction of the test stand design, construction and high power tests is presented in this paper. 相似文献