光学克里斯特逊器中的自由电子放大增强
FEL Gain Enhancement in an Optical Klystron
AI总结：
本研究通过光学克里斯特逊器结构优化，提升自由电子激光在X射线范围内的增益系数，实验显示在最佳距离下增益可达约90。
摘要：
由两个相同的小螺旋或平面振荡器通过间隙分开构成的系统——即光学克里斯特逊器（OK）——被研究。推导出零角度下自发辐射频率分布的公式。证明由于每个振荡器中形成的辐射场的构造性干涉，振荡器之间的距离（直到最佳值）增加时，自发辐射线形逐渐变窄，而辐射的光子数减少。自由电子激光（FEL）增益系数也逐渐增加，因为其与自发辐射线形的导数成正比。使用SASE XFEL的振荡器参数和LCLS的束参数，X射线范围内总增益系数约为2.5，对于不同的电子能量，在水窗频率范围内可达到约90。
英文摘要：
A system comprising two identical helical or planar undulators separated by a gap -- viz., an optical klystron (OK) -- is investigated. A formula for the frequency distribution of spontaneous radiation at zero angle is derived. It is shown that the spontaneous radiation line shape gradually narrows with increasing distance (up to an optimal value) between the undulators due to the constructive interference of the radiation fields formed in each of them, while the number of radiated photons decreases. The free-electron laser (FEL) gain coefficient also gradually increases, since it is proportional to the derivative of the spontaneous radiation line shape. Using the undulator parameters of the SASE XFEL and the bunch parameters of the LCLS, the total gain coefficient in the X-ray range is on the order of 2.5 and, for a different electron energy, reaches approximately 90 in the water window frequency range.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
