Gamma-rays from harmonically resonant betatron oscillations in a plasma wake
Gamma-rays from harmonically resonant betatron oscillations in a plasma wake
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DOI：
10.1038/nphys2090
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发表时间：
2011-11-01
期刊：
影响因子：
19.6
通讯作者：
Jaroszynski, Dino A.
中科院分区：
文献类型：
--
作者：
Cipiccia, Silvia;Islam, Mohammad R.;Jaroszynski, Dino A.
等离子体中的强激光脉冲可以将电子（1-4）加速到以厘米（5-7）为单位的GeV能量。等离子体尾流中的横向电子加速器运动（8,9）产生x射线光子，其能量取决于电子能量、电子加速器运动的振荡幅度和频率（10-12）。迄今为止，来自激光加速器电子的Betatron x射线的光谱峰值限制在1至10 keV之间（参考文献13）。在这里，我们表明，当电子与激光脉冲的后部相互作用时，电子加速器的振幅共振增强（14,15）。在高电子能量下，当激光频率是电子加速器频率的谐波时，会发生共振，导致光子能量显著增加。在700MeV光束中测量到108个伽玛射线光子，光谱峰值在20到150kev之间，峰值亮度为bbb10（23）个光子s(-1) mrad(-2) mm(-2) / 0.1%带宽，其中10(7)个光子发射在1到7MeV之间。持续时间为飞秒的伽马射线可用于成像、同位素生产、探测致密物质、国土安全和核物理。
An intense laser pulse in a plasma can accelerate electrons(1-4) to GeV energies in centimetres(5-7). Transverse betatron motion(8,9) in the plasma wake results in X-ray photons with an energy that depends on the electron energy, oscillation amplitude and frequency of the betatron motion(10-12). Betatron X-rays from laser-accelerator electrons have hitherto been limited to spectra peaking between 1 and 10 keV (ref. 13). Here we show that the betatron amplitude is resonantly enhanced when electrons interact with the rear of the laser pulse(14,15). At high electron energy, resonance occurs when the laser frequency is a harmonic of the betatron frequency, leading to a significant increase in the photon energy. 108 gammaray photons, with spectra peaking between 20 and 150 keV, and a peak brilliance > 10(23) photons s(-1) mrad(-2) mm(-2) per 0.1% bandwidth, are measured for 700MeV beams, with 10(7) photons emitted between 1 and 7MeV. Femtosecond duration gamma-rays may find uses in imaging, isotope production, probing dense matter, homeland security and nuclear physics(16).