Production of Far-infrared Coherent Synchrotron Radiation on Electron Storage Ring

电子存储环上产生远红外相干同步辐射

基本信息

批准号：
15360038
负责人：
KATOH Masahiro
金额：
$ 4.8万
依托单位：
Institute for Molecular Science (2004)Okazaki National Research Institutes (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Normally, synchrotron radiation intensity is proportional to number of electrons which contribute to the radiation. However, when the electrons are bunched into a short pulse whose length is shorter than the radiation wave length, the radiation from individual electrons is emitted coherently and the radiation intensity is proportional to the square of the number of the electrons. This phenomenon is called coherent synchrotron radiation(CSR). Since the typical number of the electrons in a storage ring is 10^<10>, the intensity of CSR can be larger than the normal synchrotron radiation by many orders of magnitudes.We have been trying to produce CSR on the electron beam circulating in a storage ring. Our approach is to create a density modulation whose typical length is shorter than the radiation wavelength, in stead of shortening the electron pulse length. As a result, we have detected very intense bursts of terahertz radiation, whose peak intensity is larger than normal radiation by 4 orders of magnitudes. These bursts were observed only in single bunch filling mode with the beam current higher than a certain threshold current. We suppose that a density modulation whose typical scale is in millimeter range, is created on an electron beam as a result of beam instability. This modulation forces the electron beam to emit such intense bursts. The typical duration of these bursts are 100 micro-seconds. The interval of the bursts is typically 10 milliseconds and varied on the beam current. This phenomenon is essentially unstable and chaotic. To utilize this intense radiation, we must control the occurrence of the bursts. We are trying to produce density modulation on an electron beam by utilizing the interaction between the electrons and laser pulses. We have already succeeded in producing intense bursts whose occurrence is controlled by an external trigger.

通常，同步加速器辐射强度与有助于辐射的电子数成正比。但是，当将电子束成短的脉冲中，其长度比辐射波长度短时，单个电子的辐射相干发射，辐射强度与电子数量的平方成正比。该现象称为相干同步辐射（CSR）。由于存储环中的典型电子数为10^<10>，因此CSR的强度可以大于许多尺寸的尺寸。我们的方法是创建一个密度调制，其典型长度比辐射波长短，而不是缩短电子脉冲长度。结果，我们检测到了Terahertz辐射的非常强烈的爆发，其峰强度比4个阶次大小大于正常辐射。仅在单束填充模式下观察到这些爆发，而梁电流高于一定阈值电流。我们认为，典型尺度在毫米范围内的密度调制是由于束不稳定性而在电子束上创建的。该调节迫使电子束发出如此强烈的爆发。这些爆发的典型持续时间为100个微秒。突发的间隔通常为10毫秒，并且在梁电流上有所不同。这种现象本质上是不稳定和混乱的。要利用这种强烈的辐射，我们必须控制爆发的发生。我们试图通过利用电子与激光脉冲之间的相互作用来在电子束上产生密度调制。我们已经成功地产生了由外部触发器控制的激烈爆发。