298 / 2023-04-26 04:33:16

Nonlinear Compton Scattering and bright narrow-band gamma-sources

Gamma-Ray;,High-order Bessel laser; relativistic electron beam; Inverse Compton scattering; X-ray source;

极端光下的基础物理学 > 辐射源

Nonlinear Compton Scattering (NCS) is a process when several or many photons scatter off a fast electron. The nonlinearity in Compton scattering becomes more pronounced at intensities of the scattered laser pulse above 10¹⁶ W/cm². This process is interesting because it can significantly increase the photon output of a Compton photon source at X- and gamma-ray energies. At low quantum recoil, the process can be described classically and using practically the same formulas as those for the undulator radiation. Important features of the NCS include: 1) generation of high-order harmonics; 2) a non-zero and at high intensities dominant contribution of radiation pressure to the effect; 3) growth of photon output in the fundamental harmonic proportional to the intensity of the laser pulse while preserving its total energy. According to the third point, it makes sense to investigate the use of powerful laser pulses to create bright narrow-band X- and gamma ray sources. Unlike an undulator, realistic laser pulses have a temporal envelope that is different from rectangular, for example, Gaussian. This leads to parasitic broadening of the Compton line due to non-uniform radiation pressure [1].

The presentation will provide an overview of NCS studies and introduce several simple optical methods [2, 3] that can help to eliminate parasitic ponderomotive line broadening and significantly increase the photon output for a narrow-band gamma source. The results of mathematical modeling for realistic laser and electron beams will be presented. Usage of NCS in future photon sources will be discussed.



References

1. Nedorezov V.G., Rykovanov S.G., Savelyev A.B. Nuclear Photonics: Results and perspectives // Phys.Usp.- 2021.-№191-С. 1281–1306


2. Seipt D., Kharin V.Yu., Rykovanov S.G. Optimizing laser pulses for narrow-band inverse Compton sources in the high-intensity regime // Phys. Rev. Lett.- 2019.-№122-С. 204802


3. Towards high photon density for Compton scattering by spectral chirp / M.A. Valialshchikov M.A., D. Seipt, V.Yu. Kharin, S.G. Rykovanov // Phys. Rev. A- 2022.-№106-С. L031501