Collision of cold ions stored in an electrostatic ion storage ring

东京都立大学作为第一个液氮冷却的E环，建造了静电离子储存环（TMU E环），成功地储存了包括亚稳态离子和大分子离子在内的各种离子。与现有的E环、奥胡斯的ELISA和KEK的ESRING相比，同时存储了不同质量的各种离子，并且凭借本研究开发的尺寸选择性束处理技术，存储、喷射特定离子。成束、去成束或加速。正如ELISA小组所证明的那样，电子环是研究长寿命亚稳态离子的理想装置，它能在几毫秒到几秒内储存离子。本文测量了双电荷CO_2的寿命。为了拟合测量的衰变曲线，需要至少三个衰变分量。关于大分子离子，富勒烯和卟啉阴离子产生的激光解吸源存储在环中。研究了卟啉阴离子的激光诱导电子脱离，重点关注延迟电子发射。中性产额的时间曲线不符合t-1依赖性，这是广泛接受的内部热离子的衰变曲线。这些结果表明，光激发的阴离子的能量分布将不同于从离子源中提取的“热”离子，并且对激发方式相当敏感。通过扫描激发波长，首次测量了气相阴离子的吸收光谱。

An electrostatic ion storage ring (TMU E-ring) was constructed in Tokyo Metropolitan University as a first LN2-cooled E-ring, and various ions including metastable ions and large molecular ions were successfully stored. In contrast to the existing E-rings, ELISA at Aarhus and ESRING at KEK, various ions with different masses were stored simultaneously, and by virtue of size-selective beam-handling techniques developed in the present study, specific ions were stored, ejected, bunched, de-bunched, or accelerated.As demonstrated by the ELISA group, E-ring is a suitable device for the study of long-life metastable ions it can store ions in several milliseconds to seconds. In the present study, lifetime of doubly charged CO_2 was measured. To fit the measured decay curve, at least three decay components were needed. Concerning large molecular ions, fullerene and porphyrin anions generated in a laser desorption source were stored in the ring. Laser-induced electron detachment of porphyrin anions was studied focusing attention onto delayed electron emission. Time profile of the neutral yield was not well fitted by t-1 dependence, which is widely accepted for the decay profile of internally hot ions. These results indicate that the energy distribution of the photo-excited anions would be different from "hot" ions extracted from the ion source, and quite sensitive to the way of excitation. By scanning excitation wavelength, absorption spectra of gas-phase anions were also measured for the first time.