Observed proton beam induced disruption of a tungsten powder sample at CERN
Observed proton beam induced disruption of a tungsten powder sample at CERN
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DOI：
10.1103/physrevaccelbeams.21.073002
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发表时间：
2018-07
影响因子：
1.7
通讯作者：
T. Davenne;P. Loveridge;R. Bingham;J. Wark;J. Back;O. Caretta;C. Densham;J. O'Dell;D. Wilcox;M. Fitton
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文献类型：
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作者：
T. Davenne;P. Loveridge;R. Bingham;J. Wark;J. Back;O. Caretta;C. Densham;J. O'Dell;D. Wilcox;M. Fitton
流化钨粉已被提出作为一个潜在的目标技术，粒子加速器的应用与非常高的功率高度集中的脉冲束。这促使在欧洲核子研究中心的HiRadMat设施进行了一系列实验，以研究钨粉样品对高能质子束脉冲的响应。主要观察结果是光束引起的粉末样品的提升，并通过高速视频记录下来。在本文中，我们考虑三种机制来解释所观察到的粉末电梯，包括空气动力学，热膨胀和感应电荷效应。对空气动力学效应的模拟表明，这不能解释观察到的喷发的规模，特别是在真空中对粉末进行测试期间。钨粒子的热膨胀引起的喷发似乎是不可信的，因为粉末倾向于吸收扰动。我们表明，观测结果可以解释的库仑爆发的钨粒子。高能束在导电性差的粉末样品中留下分布的电荷图案，这产生了电场，从而导致作用在各个带电粒子上的力。我们计算的电荷沉积，电场和由此产生的加速度，并表明这是一个合理的机制，导致观察到的爆发。我们相信颗粒导电样品对入射质子束的响应以前没有得到解释。
Fluidized tungsten powder has been proposed as a potential target technology for particle accelerator applications with very high power highly focused pulsed beams. This has motivated a series of experiments carried out at the HiRadMat facility at CERN to study the response of a tungsten powder sample to an impinging high energy proton beam pulse. The main observation was that of beam induced lifting of the powder sample which was recorded by high speed video. In this paper we consider three mechanisms to explain the observed powder lift including aerodynamic, thermal expansion and induced charge effects. Simulations of the aerodynamic effect revealed that this could not explain the magnitude of the observed eruptions especially during tests carried out with the powder in a vacuum. Thermal expansion of tungsten particles giving rise to the eruption seems implausible due to the propensity for the powder to absorb perturbations. We show that the observations can be explained by a Coulombic eruption of the tungsten particles. The high energy beam leaves a pattern of charge distributed in the poorly conducting powder sample, which creates an electric field that consequently results in a force acting on the individual charged particles. We calculate the charge deposited, the electric field and the resulting acceleration and show that this is a plausible mechanism for causing the observed eruptions. We believe the response of a granular conductive sample to an incident proton beam has not previously been explained.