低温静电离子束存储环DESIREE中旋转冷却的OH⁻离子

Rotationally Cold OH^{-} Ions in the Cryogenic Electrostatic Ion-Beam Storage Ring DESIREE.

作者信息

Schmidt H T, Eklund G, Chartkunchand K C, Anderson E K, Kamińska M, de Ruette N, Thomas R D, Kristiansson M K, Gatchell M, Reinhed P, Rosén S, Simonsson A, Källberg A, Löfgren P, Mannervik S, Zettergren H, Cederquist H

机构信息

Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden.

Institute of Physics, Jan Kochanowski University, 25-369 Kielce, Poland.

出版信息

Phys Rev Lett. 2017 Aug 18;119(7):073001. doi: 10.1103/PhysRevLett.119.073001. Epub 2017 Aug 14.

DOI:10.1103/PhysRevLett.119.073001

PMID:28949695

Abstract

We apply near-threshold laser photodetachment to characterize the rotational quantum level distribution of OH^{-} ions stored in the cryogenic ion-beam storage ring DESIREE at Stockholm University. We find that the stored ions relax to a rotational temperature of 13.4±0.2 K with 94.9±0.3% of the ions in the rotational ground state. This is consistent with the storage ring temperature of 13.5±0.5 K as measured with eight silicon diodes but in contrast to all earlier studies in cryogenic traps and rings where the rotational temperatures were always much higher than those of the storage devices at their lowest temperatures. Furthermore, we actively modify the rotational distribution through selective photodetachment to produce an OH^{-} beam where 99.1±0.1% of approximately one million stored ions are in the J=0 rotational ground state. We measure the intrinsic lifetime of the J=1 rotational level to be 145±28 s.

摘要

我们应用近阈值激光光剥离技术来表征存储于斯德哥尔摩大学低温离子束存储环DESIREE中的OH⁻离子的转动态量子能级分布。我们发现，存储的离子弛豫至13.4±0.2 K的转动温度，其中94.9±0.3%的离子处于转动基态。这与用八个硅二极管测量的存储环温度13.5±0.5 K一致，但与此前在低温阱和存储环中的所有研究形成对比，在那些研究中，转动温度总是远高于存储装置在其最低温度时的温度。此外，我们通过选择性光剥离积极改变转动分布，以产生一束OH⁻离子束，其中约一百万个存储离子中有99.1±0.1%处于J = 0转动基态。我们测得J = 1转动能级的固有寿命为145±28 s。