Theory of Coherent Radiation from Periodic Structures

在现代科学中，像GeV同步辐射装置这样的强X光子源的作用是相当重要的。毫无疑问，更加紧凑、可调谐、单色和强大的X光子源将在科学、技术和医学的各个领域带来进一步的发展。在这方面，我们必须研究一种新的机制，使这类源超越已知的相干辐射，如沟道辐射、参数x辐射等，我们正在努力寻找一种新的相干辐射机制，并解释这一领域的实验结果。以下是我们在这一问题上的主要结果。对于MeV平面沟道电子，预言了一种新型的强X光子发射。它被发射到接近电子束的布拉格角的方向。预测的X光子的光谱密度比参数X辐射的光谱密度大数百倍以上。给出了最近观测到的层状硅单晶的单色x辐射理论。数值计算结果与实验数据吻合较好。理论上基于量子力学的方法来研究绕射跃迁辐射。对沟道电子产生的非相干韧致辐射进行了计算机模拟。我们的结果与迄今尚未从理论上解释的1.3GeV沟道电子与1.04GeV光子角度关系的实验结果相一致。

In the modern science the role of strong x-photon sources such as the GeV synchrotron radiation facilities is quite important. There is no doubt that a more compact, tunable, monochromatic as well as strong x-photon source will bring a further developments in a varaety of fields of science, technology, and medicine. In this connection, we have to investigate a new mechanism for such sources beyond the known coherent radiations such as channeling radiation, parametric x radiation, etc, We are trying to find a new mechanism of coherent radiation as well as explaining experimental results in this field. Followings are our main results related on this problem.1. A new type of strong X-photon emission is predicted for MeV planar channeled electrons. It is emitted into the direction close to the Bragg angle with respect to the electron beam. The spectral density of the predicted X-photons is more than hundreds times larger than that of parametric x radiation.2. Theory of monochromatic x radiation from stratified Si single crystal observed recently has been given. Our numerical results agree with the experimental data. Theory is based on the quantum-mechanical approach to the diffracted transition radiation.3. Computer simulation on the incoherent bremsstrahlung from channeled electrons has been per-formed. Our result agrees well with the experimental result of the angular dependence of 1.04GeV photons from 1.3GeV channeled electrons electrons in Si crystals that has not been explained theoretically so far.