RF-modulated electron beams, such as those produced by an RF linear accelerator, propagating through vacuum, air, and solid matter are well known to drive signals in microwave cavities and waveguides via interactions with these structures. Past experiments with a microwave waveguide in a radiation-shielded vault indicated the presence of a multipath propagation phenomenon, hypothesized to be a result of reflections of RF-modulated x rays. In this work, we study the signals induced in a microwave coaxial cable from nearby beam interactions with materials commonly found in accelerator facilities in order to better understand RF production and propagation in these environments. Our results show that (1) when an RF-modulated electron beam is incident on a block of aluminum, lead, or concrete, the frequency content of the induced microwave signals is strongly dependent on the orientation of the block and the relative position of the detector, (2) at least some of the detected signals are consistent with reflections off of the blocks, and (3) beam interactions with the blocks can induce appreciable microwave signals in detectors located tens of cm from the block.

中文翻译：

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调制电子束与固体物质相互作用产生的微波辐射

众所周知，RF调制电子束（例如由RF线性加速器产生的电子束）通过真空，空气和固体传播，通过与这些结构的相互作用来驱动微波空腔和波导中的信号。过去在辐射屏蔽库中使用微波波导进行的实验表明存在多径传播现象，该现象被认为是RF调制X射线反射的结果。在这项工作中，我们研究了微波同轴电缆中由于附近的光束与加速器设备中常见的材料相互作用而产生的信号，以便更好地了解这些环境中的射频产生和传播。我们的结果表明（1）当射频调制的电子束入射到一块铝，铅或混凝土块上时，