Destruction Study of Tantalum Target Impacted by 12MeV Electron Beam

Abstract：

The radiation destructive appeatance caused by intensive electron beam current with 12MeV energy reveals different mechanism of fracture from those caused by lower energy electron or X-ray due to the strong penetrating ability of the electron. In the paper, the fracture profiles of the 1.2mm Ta target, which is destructed by 12MeV electron beam, are studied using microscope and scanning electron microscope. The result indicates mechanical tear is the major reason, and moreover, the tear fracture is almost symmetrical. In order to understand this, the energy deposit of electron beam along the depth of the target is given out by Monte-Carlo simulation, which is also symmetrical and higher in center, lower in sides. A preliminary conclusion on the major destructing mechanism of the target is drawn out: 12MeV electron beam, which has strong penetration ability, can heat the whole target almost at the same time. The expansion of the center part of the target is constrained by the boundary which results in two shock waves with most destructive power produced in the two sides of center. After the shock waves reach the free surfaces of the target, by wave reflection, two rarefaction waves will propagate inward, then symmetric tearing happens when the two waves meet at the center region of the target.