Focusing of short-pulse high-intensity laser-accelerated proton beams
Focusing of short-pulse high-intensity laser-accelerated proton beams
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DOI：
10.1038/nphys2153
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发表时间：
2012-02-01
期刊：
影响因子：
19.6
通讯作者：
Beg, Farhat N.
中科院分区：
文献类型：
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作者：
Bartal, Teresa;Foord, Mark E.;Beg, Farhat N.
通过强烈的激光与物质相互作用产生高能（>50 MeV）质子（10(18)-10(21) W cm(-2)；参考文献1-7）的最新进展开辟了新的研究领域，应用于放射线照相(8)、肿瘤学(9)、天体物理学(10)、医学成像(11)、高能密度物理学(12-14)和离子-质子束快速点火（15-19）。随着曲面聚焦质子的发现(20,21)，改进的聚焦技术将推动这些领域的快速进步。在这里，我们报告了使用锥形靶产生和聚焦质子束的首次研究。我们清楚地表明，在开放和封闭（锥形）几何形状中，聚焦受到光束中电场的强烈影响，从而使轴附近的轨迹弯曲。同样在锥体几何形状中，鞘层电场有效地将质子束“引导”通过锥体尖端，从而显着改善了束流聚焦特性。这些结果与粒子模拟非常吻合，并为许多未来的应用提供了物理基础。
Recent progress in generating high-energy (>50 MeV) protons from intense laser-matter interactions (10(18)-10(21) W cm(-2); refs 1-7) has opened up new areas of research, with applications in radiography(8), oncology(9), astrophysics(10), medical imaging(11), high-energy-density physics(12-14), and ion-proton beam fast ignition(15-19). With the discovery of proton focusing with curved surfaces(20,21), rapid advances in these areas will be driven by improved focusing technologies. Here we report on the first investigation of the generation and focusing of a proton beam using a cone-shaped target. We clearly show that the focusing is strongly affected by the electric fields in the beam in both open and enclosed (cone) geometries, bending the trajectories near the axis. Also in the cone geometry, a sheath electric field effectively 'channels' the proton beam through the cone tip, substantially improving the beam focusing properties. These results agree well with particle simulations and provide the physics basis for many future applications.