A large-scale proton or ${\mathrm{H}}^{-}$ accelerator often requires a jump in radio frequency, typically in the beam velocity range of $\beta =0.4–0.6$. The MYRRHA linac has two frequency jumps: one at $\beta \cong 0.2$ and another one in the typical beam velocity range at $\beta =0.56$. Using the MYRRHA linac as an example, this study investigates two new solutions, whereby the frequency jump in the range of $\beta =0.4–0.6$ is eliminated. A single frequency jump at $\beta \cong 0.2$ can shorten the whole linac considerably and reduce the construction and operation costs. The proposed frequency jump sections will use 704.4 MHz radio-frequency quadrupole and cross-bar $H$-type drift tube linear accelerators. To ensure a safe and reliable cw operation at such very high frequency for these kinds of accelerating structures, careful design studies with respect to beam dynamics and rf structures including water-cooling channels have been performed. The results demonstrated the feasibility of both solutions.

中文翻译：

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使用704.4 MHz射频四极杆和横杆H型漂移管线性加速器的跳频

大型质子或 ${\mathrm{H}}^{-}$ 加速器通常需要跳跃无线电频率，通常在光束速度范围内 $\beta =0.4–0.6$。MYRRHA直线加速器有两个跳频：一个在$\beta \cong 0.2$ 另一个在典型的光束速度范围内 $\beta =0.56$。以MYRRHA直线加速器为例，本研究研究了两种新的解决方案，即频率跳变范围为$\beta =0.4–0.6$被淘汰。单频跳变$\beta \cong 0.2$可以大大缩短整个直线加速器，并降低建造和运营成本。拟议的跳频部分将使用704.4 MHz射频四极杆和交叉开关$H$型漂移管线性加速器。为了确保此类加速结构在如此高的频率下安全，可靠地连续波操作，已经对射束动力学和包括水冷通道在内的RF结构进行了认真的设计研究。结果证明了两种解决方案的可行性。