Intense pulsed neutron fluences are generated by a high-energy (>10 MeV) proton beam using the beam-target method on the HERMES III facility at Sandia National Laboratories [J. J. Ramirez et al., in Proceedings of the 7th International Conference on High Power Particle Beams (Kernforschungszentrum, Karlsruhe GmbH, Karlsruhe, Germany, 1988), p. 148]. In order to generate the high-energy proton beam, a radial ion diode previously developed and fielded at the 6-MeV level in negative polarity was extended in performance to the 15-MeV level. This performance increase is described along with the development of a more durable hardware set to withstand the much more potent 15-MeV proton beam. An extensive series of simulations is developed to characterize the neutrons produced by the proton–target interaction. Particle-in-cell simulations describe the electron and ion dynamics, while Monte Carlo simulations characterize the neutron output. Due to differing estimates of proton beam voltage and current between the respective simulations, we make an approximate estimate of 13.5-MeV to 15-MeV and 120-kA ion beams at peak power in a 40 ns FWHM pulse. Simulations indicate that a total of 1.7 × 10¹³ neutrons are generated into 4π. Comparison of the neutron output predictions with a limited set of neutron flux measurements suggests a flux level of ∼1 × 10¹⁰ neutrons/cm² to 10 × 10¹⁰ neutrons/cm² over an approximately few tens of cm² area at the relevant application location. This effort also contributes to physics understanding of the use of inductive voltage adder platforms to drive ion-beam diode loads.

中文翻译：

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使用15 MeV HERMES III离子束通过束-靶相互作用产生脉冲高能中子爆发

在桑迪亚国家实验室的HERMES III设施上使用束靶法，通过高能（> 10 MeV）质子束产生强脉冲中子注量[JJ Ramirez等。，在第七届高功率粒子束国际会议论文集中（Kernforschungszentrum，Karlsruhe GmbH，德国卡尔斯鲁厄，1988年），第2页。148]。为了产生高能质子束，先前开发并以6MeV负极水平部署的径向离子二极管的性能扩展到15MeV等级。这种性能的提高与更耐用的硬件套件的发展一起得到了描述，该硬件套件可承受更强大的15-MeV质子束。开发了一系列广泛的模拟来表征质子-目标相互作用产生的中子。细胞粒子模拟描述了电子和离子的动力学，而蒙特卡洛模拟则描述了中子的输出。由于各个模拟之间质子束电压和电流的估算值不同，因此我们将估算值近似为13。在40 ns FWHM脉冲中以峰值功率产生5MeV至15MeV和120kA的离子束。仿真表明，总数为1.7×10^13个中子产生4π。将中子输出预测与一组有限的中子通量测量结果进行比较，表明在相关应用中，在大约几十cm ^2的面积上，通量水平约为1×10 ¹⁰中子/ cm ²至10×10 ¹⁰中子/ cm ²位置。这项工作还有助于物理上理解使用感应电压加法器平台来驱动离子束二极管负载。