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Recently, Xu Zhizhan, the State Key Laboratory of Laser Field Physics, Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, and Li Ruxin's research team have made breakthroughs in the research of ultra-high intensity gamma gamma ray sources driven by ultra-short lasers. Accelerated high-performance high-energy electron beam and laser collision to generate ultra-high intensity quasi-monochromatic MeV gamma ray source with super-ultra-short laser driven cascaded wakefield acceleration. Its maximum peak brightness reaches 3×1022 photons s- 1 mm-2 mrad-2 0.1%BW, which is more than one order of magnitude higher than the brightness of similar gamma ray sources reported internationally, is 100,000 times higher than the peak brightness of the traditional gamma-ray source energy region. The relevant research results were published in Scientific Reports 6, 29518 (2016).
The inverse Compton scattering based on relativistic electron beam and laser collision is currently the most effective way to generate high energy gamma rays. High-energy gamma ray sources have extremely important application values ​​in many fields such as nuclear physics and nuclear photonics, particle physics, non-destructive testing, materials science, medical diagnosis, nuclear energy, and space technology. Many countries in the world, including China, are actively building gammas. The horse ray source, but the gamma ray source device based on the traditional accelerator is bulky and expensive, which greatly limits its development and application. Ultra-short ultra-short laser-driven plasma wakefield electron acceleration is a new electronic acceleration mechanism. Its acceleration gradient is more than three orders of magnitude higher than conventional electron accelerators, which can greatly reduce the scale and cost of the system. Compton gamma ray source device miniaturization. In addition, the relativistic electron beam generated by super-ultra-short laser acceleration naturally has the characteristics of femtosecond-scale pulse width and micron-scale size, which makes the gamma-ray pulse has the remarkable advantages of ultra-short pulse and ultra-high brightness which are difficult to obtain by the traditional methods.
In recent years, the research team of Shanghai Institute of Optics and Engineering has carried out unique research in the field of electron acceleration of the laser tail wave field. The first time in the world, it successfully achieved a new scheme for quasi-single energy high-energy electron acceleration in the cascaded double-tailed wave field and achieved GeV level. Quasi-single energy beam and other important research results [Phys. Rev. Lett. 107, 035001 (2011); Appl. Phys. Lett. 103, 243501 (2013)]. In the development of this Compton gamma ray source, a self-developed high-repetition-frequency 200 TW super-ultra-short laser device was used to optimize the electron injection phase in the electron acceleration of the cascaded wake field to obtain a peak energy of 200 ~500 MeV range, energy dispersive ~1%, power ~50pC, divergence angle <0.4 mrad, pulse width ~10fs high performance quasi-single energy electron beam. And using the plasma mirror reflection drive laser and the electron beam to achieve self-synchronous accurate colliding, resulting in a quasi-monochromatic gamma ray source with peak energy in the range of 0.2-2 MeV. The maximum peak brightness reaches 3×1022 photons s-1 mm-2 mrad-20.1%BW, which is 100,000 times higher than that of the traditional gamma-ray source isopotential region, and the single-shot gamma photon number reaches 5×107 photons.
This miniaturized ultra-high brightness and quasi-monochromatic MeV gamma ray source will have a wide range of applications in nuclear physics and nuclear photonics, materials science, nondestructive testing, and medical diagnostics.
The diagnostic measurement of the gamma ray source of this study was completed in cooperation with the Northwest Institute of Nuclear Technology.
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