Various graphite targets with a tantalum core were exposed to 440 GeV pulsed proton beams at the HiRadMat facility at CERN. The dynamic response was investigated by monitoring the surface velocity of the samples by laser Doppler vibrometry. The study comprises different graphite grades, such as polycrystalline, expanded and carbon-fiber reinforced graphite, and low-density graphitic foams, all candidates for beam-intercepting devices in high-power accelerators. The purpose of the tantalum core is to concentrate the large energy deposition in this high-density material that withstands the localized beam-induced temperature spike. The generated pressure waves are estimated to result in stresses of several hundred MPa which subsequently couple with the surrounding graphite materials where they are damped. Spatial energy deposition profiles were obtained by the Monte Carlo code FLUKA and the dynamic response was modelled using the implicit code ANSYS. Using advanced post-processing techniques, such as fast Fourier transformation and continuous wavelet transformation, different pressure wave components are identified and their contribution to the overall dynamic response of a two-body target and their failure mode are discussed. We show that selected low-intensity beam impacts can be simulated using straight-forward transient coupled thermal/structural implicit simulations. Carbon-fiber reinforced graphites exhibit large (macroscopic) mechanical strength, while their low-strength graphite matrix is identified as a potential source of failure. The dynamic response of low-density graphitic foams is surprisingly favourable, indicating promising properties for the application as high-power beam dump material.

中文翻译：

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受脉冲 440-GeV 质子束影响的具有钽核的石墨靶的动态响应

在欧洲核子研究中心的 HiRadMat 设施中，具有钽芯的各种石墨靶暴露于 440 GeV 脉冲质子束。通过激光多普勒振动测量法监测样品的表面速度来研究动态响应。该研究包括不同的石墨等级，例如多晶、膨胀和碳纤维增强石墨以及低密度石墨泡沫，所有这些都是高功率加速器中光束拦截装置的候选材料。钽芯的目的是将大能量沉积集中在这种高密度材料中，以承受局部光束引起的温度尖峰。据估计，产生的压力波会导致数百兆帕的应力，这些应力随后与周围的石墨材料耦合，在那里它们受到阻尼。空间能量沉积分布由蒙特卡罗代码 FLUKA 获得，动态响应使用隐式代码 ANSYS 建模。使用先进的后处理技术，例如快速傅立叶变换和连续小波变换，可以识别不同的压力波分量，并讨论它们对二体目标整体动态响应的贡献及其失效模式。我们表明，可以使用直接瞬态耦合热/结构隐式模拟来模拟选定的低强度光束撞击。碳纤维增强石墨表现出较大的（宏观）机械强度，而它们的低强度石墨基体被认为是潜在的失效源。低密度石墨泡沫的动态响应出人意料地有利，