Rudy on Ge V-electron acceleration with table top ultrashort high peak power lasers

这个项目的目的是为了产生GeV电子：10TW激光系统输出功率和指向的稳定；2 .电子等离子体波白光探头观测技术的建立。3 .强激光在长空心毛细管中的传播及其观测；用10TW激光脉冲泵浦长毛细管产生GeV电子。为了实现这些主题，我们必须解决一个技术问题和一个物理问题。为了产生GeV电子束，必须准备较长的加速长度。然后我们开发了一种带有中空纤维的毛细管靶系统。我们用精细的中空纤维分隔靶室。通过使用一种精细的中空纤维，靶室被差分泵降。这样就可以在聚焦侧保持足够高的真空，同时在空心毛细管中填充足够密度的气体靶。由于目标可以一枪一枪地交换，所以对准应该尽可能地容易。然后，我们准备了适当的对齐机制。亚mj级飞秒脉冲成功通过大气中空毛细管靶，而GeV电子停滞未加速。这种5mm的传播产生了强烈的随光连续体。其次，对GeV电子能谱仪（ESN）用成像板（IP）探测器进行了绝对定标。为了校准，我们使用了Spring-8同步加速器环的直线加速器。最后，我们产生了亚十飞秒的探测脉冲，用于观察电子等离子体波的动力学。本实验在日本原子能机构关西光子科学研究所进行。利用黄麻10激光系统产生超短脉冲。对大阪大学的激光系统进行了改进，为最终放大器准备了洁净室和两个大YAG激光器。

The aim of this project was followings for generating GeV electrons: 1. Stabilization of output power and pointing of 10TW laser system, 2. Establishment of the observation technique for electron plasma wave with white light probe, 3. Propagation of intense laser light in a long hollow capillary tube, and its observation, and 4. GeV electron generation with a long capillary pumped by 10TW laser pulses.For the sake of these themes, we have to solve a technical problems and physical problems. For generating GeV electreon beam, we have to prepare a long acceleration length. Then we developed a capillary target system with a hollow fiber. We divided a target chamber with a fine hollow fiber. By using a fine hollow fiber, a target chamber is differentially pumped down. Then we can keep comparatively high enough vacuum at the focusing side, while the hollow capillary could be filled with a gaseous target with enough density. As the target could be exchanged shot by shot, the alignment should be performed as easy as possible. Then, we have prepared the adequate alignment mechanism. The sub-mJ class femtosecond pulses were successfully passed though the hollow capillary target at the atmosphere, while the GeV electrons stall not accelerated. The strong while light continuum have been generated by this 5mm propagation. Next, we have performed the absolute calibration of the Imaging Plate (IP) detector which is used for the electron spectrometer (ESN) of GeV electrons. For this calibration, we have used the linac for Spring-8 synchrotron ring. Finally, we have generated sub-ten femtosecond probe pulse for observing the dynamics of electron plasma wave. This experiment was held at Kansai Photon Science Institute, JAEA. JUTE 10 laser system was used for generating this ultrashort prove pulse. The laser system in Osaka University was improved by preparing clean room and two big YAG lasers for final amplifier.