RS-20MR High-Current Relativistic Electron Beam Generator Based on a Plasma Opening Switch and Its Applications
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RS-20MR High-Current Relativistic Electron Beam Generator Based on a Plasma Opening Switch and Its Applications G. I. Dolgacheva, E. D. Kazakova,*, Yu. G. Kalinina, D. D. Maslennikova, and A. A. Shvedova a
National Research Center “Kurchatov Institute,” Moscow, 123098 Russia *e-mail: [email protected] Received July 23, 2018; revised October 24, 2018; accepted October 25, 2018
Abstract—A modified scheme of the RS-20MR generator is presented that can be used not only as a source of high-power pulsed hard X-ray emission (the dose power per 1-L volume in atmospheric air exceeds 1010 rad/s) but also as a tool to study various processes occurring under the interaction of high-current electron beams with materials: excitation and propagation of shock waves, destruction of solids, etc. Due to specific properties of the sharpening system, the diode voltage pulse has a relatively steep front, which ensures the dominance electrons with energies of about 1 MeV in the beam. For electron beams with currents of I = 20–100 kA and particle energies of E ≥ 0.5 MeV, isochoric energy release can be achieved in the volume of the irradiated sample. This can lead to substantial changes in the formation mechanism of a shock wave and the character of damage it causes. The results of the first experiments of this kind are reported. DOI: 10.1134/S1063780X19030048
1. INTRODUCTION High-power pulsed accelerators of relativistic electron beams (REBs) find applications in experiments on the generation and analysis of shock waves [1], investigation of material strength under pulsed loads [2], and changes in the material structure [3]. When the local energy density reaches 105 J/cm2, the jump in the pressure can reach ~1 Mbar. Experiments with ~100-ns pulses in which the electron energy exceeds 500 keV deserve special attention. In this case, the volume energy release is isochoric. Isochoric heating of the target occurs when the beam duration t0 is much shorter than the unloading time tр of the energy release zone (t0 ! t р ). Here, t р = λ/(СS )' , where λ is the mean free path of an electron in the material and (СS )' is the speed of sound in the energy release zone. The latter is only slightly higher than the speed of sound СS in a cold target. Therefore, we can assume that t р = λ/СS . Such conditions can be created by either X-ray emission of the corresponding hardness or an electron beam of sufficient energy, which is substantially more beneficial from the energy point of view. In this case, the shock wave does not have sufficient time to carry material and charge outside of a small energy-release volume, and the pressure pulse forms according to a somewhat different scenario compared to that in the case of a surface impact. In addition, the electric effects related to space charge accumulation in the bulk of the material affect the processes of material destruction. Such a scenario is of interest not only
from the point of view of applications related to material strength under exposure to extreme ionizing ra
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