分类: 核科学技术 >> 粒子加速器 提交时间: 2021-12-31
摘要: Precise measurements of the cavity forward (Vf) and reflected signals (Vr) are essential for characterizing other key parameters such as the cavity detuning and forward power. In practice, it is challenging to measure Vf and Vr precisely because of crosstalk between the forward and reflected channels (e.g., coupling between the cavity reflected and forward signals in a directional coupler with limited directivity). For DESY, a method based on the cavity differential equation was proposed to precisely calibrate the actual Vf and Vr. In this study, we verified the validity and practicability of this approach for the Chinese ADS front-end demo superconducting linac (CAFe) facility at the Institute of Modern Physics and a compact energy recovery linac (cERL) test ma#2;chine at KEK. At the CAFe facility, we successfully calibrated the actual Vf signal using this method. The result demonstrated that the directivity of directional couplers might seriously affect the accuracy of Vf measurement. At the cERL facility, we calibrated the Lorentz force detuning (LFD) using the actual Vf. Our study confirmed that the precise calibration of Vf significantly improves the accuracy of the cavity LFD measurement.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: The study presents an investigation of irradiation resistance properties of Ti3AlC2 under 500 keV He ions irradiation with the doses ranging from 5.0 1016 to 1.0 1018 ions cm 2 at certain temperatures, like room temperature (RT), 300 and 500 °C. X-ray diffraction (XRD) and Transmission electron microscopy (TEM) are used to study the evolution of structural damage and the behavior of deposited He ions respec- tively. XRD analysis reveals that for the highest dose irradiation ( 52 dpa at peak), no amorphization occurs. And the structural recovery of Ti3AlC2 is more significant accompanied with the gradual disap- pearance of the irradiation-induced TiC phase as the temperature rises from RT to 300 and to 500 °C with the same dose irradiation. TEM observations show that He bubbles appear in the shapes of sphere, string and platelet but no big bubbles are formed for all irradiations. Moreover, no large cracks form in the sam- ple implanted with the highest helium concentration of 6.4 105 appm.