Non-invasive characterisation of a laser-driven positron beam
Non-invasive characterisation of a laser-driven positron beam
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DOI：
10.1088/1361-6587/ab7e81
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发表时间：
2020-02
影响因子：
2.2
通讯作者：
Aaron Alejo;G. M. Samarin;Richard Warwick;Connor McCluskey;G. Cantono;T. Ceccotti;S. D. Dufrénoy;Pascal Monot;G. Sarri
中科院分区：
文献类型：
--
作者：
Aaron Alejo;G. M. Samarin;Richard Warwick;Connor McCluskey;G. Cantono;T. Ceccotti;S. D. Dufrénoy;Pascal Monot;G. Sarri
本文报道了一种间接的、非侵入性的方法，可以同时测量激光尾场加速电子束通过高Z转换靶时产生的超相对论正电子束的能量相关发射度和源尺寸。正电子的几何发射率与散射电子的几何发射率之间的强相关性使得通过监测散射电子可以高精度地推断出前者。该技术已经在原理验证实验中进行了测试，对于100 MeV的正电子，我们推断几何发射度和源尺寸分别为100 μm +100 μm和De+150 μm。这与数值预测的在GeV级实现亚微米几何发射度和微米级源尺寸的可能性是一致的。
We report on an indirect and non-invasive method to simultaneously characterise the energy-dependent emittance and source size of ultra-relativistic positron beams generated during the propagation of a laser-wakefield accelerated electron beam through a high-Z converter target. The strong correlation of the geometrical emittance of the positrons with that of the scattered electrons allows the former to be inferred, with high accuracy, from monitoring the latter. The technique has been tested in a proof-of-principle experiment where, for 100 MeV positrons, we infer geometrical emittances and source sizes of the order of ϵe+≈ 3 µm and De+≈ 150 µm, respectively. This is consistent with the numerically predicted possibility of achieving sub-µm geometrical emittances and micron-scale source sizes at the GeV level.