Development of a detection system for elastic electron scattering experimente at electron storage rings

为了研究短寿命放射性同位素(RI)的内部结构，我们提出了一种实现电子散射实验的新方案。这个方案，SCRIT，是基于众所周知的电子储存环上的离子俘获现象。在这种离子俘获的帮助下，SCRIT在存储环中的循环电子束上形成了一个局域RI靶，通过数值模拟发现，它的光度超过10^&lt；27&gt；/cm^2/S。这个光度足够高，可以测量弹性散射截面来确定电荷分布。为了证明它的可行性，已经建造了一个SCRIT原型，并安装在京都大学KSR现有的电子存储环上。进行了一系列的测试测量。到目前为止进行的测试实验已经表明，SCRIT原型对存储环的寿命和最大存储束流等性能没有任何负面影响。通过额外的…更多来自SCRIT的离子，我们已经清楚地证实，外部注入的Cs^&lt；1+&gt；离子稳定地捕获在SCRIT中约一秒，正如数值模拟所预期的那样。SCRIT系统已被证明是一种新型的离子陷阱。捕获离子的数量为107个数量级，也符合预期。被探测离子的电荷态的增长强烈地表明，由于电子束内的离子不断地被电子束进一步电离，所有被捕获的离子都分布在电子束内。在这个研发的实验中，光度预计在102.5/cm~2/S左右，而在韧致辐射测量中还没有观察到这种光度的直接证据。为了减少韧致辐射探测器的巨大本底，需要对光束传输进行修改。此外，还将安装另一个探测系统，以获得捕获离子与电子束重叠的直接证据。较少

We have been proposing a novel scheme to realize electron-scattering experiments for internal-structure studies of short-lived radioactive isotopes(RI). This scheme, SCRIT, is based on well-known ion-trapping phenomena at electron-storage rings. With a help of this ion trapping, SCRIT forms a localized RI target on a circulating electron beam in a storage ring, and is found by a numerical simulation to provide a luminosity of more than 10^<27>/cm^2/s. This luminosity is high enough to measure the elastic scattering cross section to determine the charge distribution.In order to demonstrate its feasibility, a SCRIT prototype has been constructed, and installed at an existing electron storage ring, KSR, Kyoto University. A series of test measurements has been done. The test experiments conducted so far have already revealed that the SCRIT prototype does not have any negative influence on the storage-ring performances, such as the lifetime and maximum storage beam current.By means of extra … More cting ions from SCRIT, we have clearly confirmed that externally injected Cs^<1+> ions were stably trapped in SCRIT about one second, as expected in a numerical simulation. The SCRIT system has been demonstrated to work as a new type of ion trap. The number of trapped ions were an order of 107, which is also in good agreement with the expectation. The growth of the charge states of detected ions strongly indicates that all trapped ions distribute inside the electron beam, since the ions inside the electron beam are continuously further ionized by the electron beam.In this R & D experiment, the luminosity is expected to be on the order of 102.5/cm2/s, whereas no direct evidence of this luminosity has yet been observed in the bremmstrahlung measurements. A modification of the beam transport is to be made in order to reduce the huge background for the bremsstrahlung detector. In addition, another detection system is to be installed to obtain direct evidence for the overlapping of trapped ions with the electron beam. Less