Study of the Ultracold and Ultrafast Beam-Cooling with a Superconducting Electron Cooler

超导电子冷却器超冷超快束流冷却研究

• 批准号: 08504002
• 负责人: TANABE Tetsumi
• 金额: $ 29.7万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08504002/
• 关键词: Accelerator; Electron Cooling; Superconducting Magnet; Atomic Physics; Atomic Collisions; Dissociative Recombination

An electron cooling method has widely been used in the atomic physics research as well as accelerator technology. The cooling time and the final accuracy in experiments are determined by the electron temperature. The electron beam has initially an energy width (or temperature) of about 100 meV,since electrons are emitted from a hot cathode. However, electron temperature can be reduced to a level less than the cathode temperature by expanding the electron beam adiabatically in a gradually decreasing solenoid field. This method is called 'adiabatic expansion method' and the electron temperature decreases in inverse proportion to an expansion factor. Based on this principle, we modified the existing electron system to the adiabatic expansion type. In the fiscal 1996, we designed and constructed an superconducting electron cooler with a magnetic field of 3.5 T and realized an expansion factor of 100 resulting in an electron temperature of 1 meV for the first time in the world. The supercon … More ducting magnet is liquid-helium free, which realized a compact design and a simple operation. The cooler opened the way to the super-fast beam cooling and extremely high-accuracy experiments. In the fiscal 1996-1997, highly accurate atomic collision experiments have been performed with this cooler. Dissociative recombination (DR) of molecular ions is one of the important processes in the upper atmosphere and the outer space. The DR of HeH^+ isotopes were studied with the extremely low-temperature electron beam of the order of 1 meV produced by the superconducting electron cooler at the storage ring TARN II.The DR spectra show a fine new structure and a clearisotope dependence in the low energy region. Those features are well reproduced by the theoretical calculations based on a multichannel quantum-defect theory. According to the theory, the newly observed structure is an evidence of a new indirect mechanism. These results on the cooler and the physics experiments have been presented at the domestic conferences in Osaka and at Kobe, and the foreign conferences in Vancouver, Vienna and Heidelberg. We also started the feasibility study of atomic collision experiments with the new cooler on many other ions. Less

电子冷却方法在原子物理研究和加速器技术中有着广泛的应用。实验中的冷却时间和最终精度取决于电子温度。电子束最初具有约100 meV的能量宽度（或温度），因为电子从热阴极发射。然而，通过在逐渐减小的螺线管场中膨胀电子束，可以将电子温度降低到小于阴极温度的水平。这种方法被称为“绝热膨胀法”，电子温度与膨胀因子成反比例下降。基于这一原理，我们将现有的电子系统修改为绝热膨胀型。在1996财政年度，我们设计并建造了一个超导电子冷却器，磁场为3.5 T，并实现了膨胀系数为100，导致电子温度为1 meV的第一次在世界上。超级骗局 ...更多信息 导管磁体不含液氦，实现了紧凑的设计和简单的操作。该冷却器为超快速束流冷却和极高精度实验开辟了道路。在1996-1997年度，利用该冷却器进行了高精度的原子碰撞实验。分子离子的解离复合（DR）是高层大气和外太空的重要过程之一。利用储存环TARN II上的超导电子冷却器产生的1 meV量级的极低温电子束研究了HeH^+同位素的DR。DR谱显示出精细的新结构和低能区明显的同位素依赖性。基于多通道量子亏损理论的理论计算很好地再现了这些特征。根据该理论，新观察到的结构是一种新的间接机制的证据。在大坂和科比举行的国内会议上，以及在温哥华、维也纳和海德堡举行的国外会议上，都提出了关于冷却器和物理实验的结果。我们还开始了用新冷却器对许多其他离子进行原子碰撞实验的可行性研究。少

项目成果

Tetsumi Tanabe: "FIRST OPERATION OF THE LIQUID-HELIUM-FREE SUPERCONDUCTING ELECTRON COOLER AT THE TARN II STORAGE RING" Proceedings of the XVI RCNP Osaka International Symposium on Multi-GeV High-Performance Accelerators and Related Technology, Osaka, Mar

Tetsumi Tanabe：“TARN II 存储环上无液氦超导电子冷却器的首次运行”第 XVI RCNP 大阪国际多 GeV 高性能加速器及相关技术研讨会论文集，3 月，大阪

Tetsumi Tanabe: "Liquid-Helium-Free Superconducting Electron Cooler at the Storage Ring TARN II" Proc.of the Fifth Futopean Particle Accelerator Conference,Sitges (Barcelona),Spain. 1190-1192 (1996)

Tetsumi Tanabe：“存储环 TARN II 上的无液氦超导电子冷却器”，第五届 Futopean 粒子加速器会议，西班牙锡切斯（巴塞罗那）。

Tetsumi Tanabe: "Operation of the Superconducting Electron Cooler at the Cooler Ring TARNII" Proc.of the 11th Symposium on Accelerator Science and Technology Harima Science Garden City. 104-106 (1997)

田边哲美：“冷却环TARNII处的超导电子冷却器的运行”第11届加速器科学技术研讨会播磨科学花园城论文集。

Tetsumi Tanabe: "Liquid-Helium-Free Superconducting Electron Cooler at the Storage Ring TARN II" Proc.of the Fifth European Particle Accelerator Conference,Sitges(Barcelona),Spain. 1190-1192 (1996)

Tetsumi Tanabe：“储存环 TARN II 上的无液氦超导电子冷却器”，第五届欧洲粒子加速器会议论文集，西班牙锡切斯（巴塞罗那）。

Tetsumi Tanabe: "Dissociative Recombination of Molecular Ions with a 1-meV Temperature Electron Beam from a Superconducting Electron Cooler at the TARN II Storage Ring" Abstracts of contributed Papers on the XXth International Conference on The Physics of

Tetsumi Tanabe：“分子离子与来自 TARN II 存储环超导电子冷却器的 1-meV 温度电子束的解离重组”第 20 届国际物理会议投稿论文摘要