Betatron radiation from a beam driven plasma source
Betatron radiation from a beam driven plasma source
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来自光束驱动等离子体源的电子感应加速器辐射
DOI：
10.1063/1.4773784
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发表时间：
2013
影响因子：
4
通讯作者：
S. Corde
中科院分区：
文献类型：
--
作者：
M. Litos;S. Corde
电子束驱动等离子体尾流中的电子感应加速器振荡产生的光子提供了硬X射线和伽马射线的独特强度和高能量源。这种电子感应加速器辐射不仅因为其高强度和光谱特性而令人感兴趣，而且还因为它可以用作束匹配到等离子体中的诊断，这对于最大化等离子体加速器级的能量提取效率至关重要。在SLAC，伽马射线探测装置已安装在FACET光束线的转储区域，在那里可以观察到来自E200等离子体韦克菲尔德加速实验中使用的等离子体源的电子感应加速器辐射。FACET处的超密度高能束（2 x 10{sup 10}电子，20 x 20 {micro}m{sup 2}光斑，20-100 {micro}m长度，20 GeV能量）在被送入标称密度为{approximate} 1 x 10{sup 17} cm{sup-3}的等离子体源时，将产生类似同步加速器的光谱，其临界能量可达数十MeV。辐射的强度可以通过向见证聚束的质心引入径向偏移来增加，这可以通过使用横向偏转RF腔在FACET处实现。E200伽马射线探测器更多»有两个主要部件：一个30 x 35 cm{sup 2}的磷光屏，用于观察辐射的横向范围;一个采样电磁量能器，配备光电二极管，用于测量轴上光谱。为了估计光谱，在量热计上观察到的强度模式与高斯积分同步加速器光谱拟合，并与模拟进行比较。介绍了FACET首次用户运行（2012年4月至6月）的结果和观察结果。«少
Photons produced by the betatron oscillation of electrons in a beam-driven plasma wake provide a uniquely intense and high-energy source of hard X-rays and gamma rays. This betatron radiation is interesting not only for its high intensity and spectral characteristics, but also because it can be used as a diagnostic for beam matching into the plasma, which is critical for maximizing the energy extraction efficiency of a plasma accelerator stage. At SLAC, gamma ray detection devices have been installed at the dump area of the FACET beamline where the betatron radiation from the plasma source used in the E200 plasma wakefield acceleration experiment may be observed. The ultra-dense, high-energy beam at FACET (2 x 10{sup 10} electrons, 20 x 20 {micro}m{sup 2} spot, 20-100 {micro}m length, 20 GeV energy) when sent into a plasma source with a nominal density of {approx} 1 x 10{sup 17} cm{sup -3} will generate synchrotron-like spectra with critical energies well into the tens of MeV. The intensity of the radiation can be increased by introducing a radial offset to the centroid of the witness bunch, which may be achieved at FACET through the use of a transverse deflecting RF cavity. The E200 gamma ray detectormore » has two main components: a 30 x 35 cm{sup 2} phosphorescent screen for observing the transverse extent of the radiation, and a sampling electromagnetic calorimeter outfitted with photodiodes for measuring the on-axis spectrum. To estimate the spectrum, the observed intensity patterns across the calorimeter are fit with a Gaussian-integrated synchrotron spectrum and compared to simulations. Results and observations from the first FACET user run (April-June 2012) are presented.« less