Schmidt H T, Thomas R D, Gatchell M, Rosén S, Reinhed P, Löfgren P, Brännholm L, Blom M, Björkhage M, Bäckström E, Alexander J D, Leontein S, Hanstorp D, Zettergren H, Liljeby L, Källberg A, Simonsson A, Hellberg F, Mannervik S, Larsson M, Geppert W D, Rensfelt K G, Danared H, Paál A, Masuda M, Halldén P, Andler G, Stockett M H, Chen T, Källersjö G, Weimer J, Hansen K, Hartman H, Cederquist H
Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden.
Rev Sci Instrum. 2013 May;84(5):055115. doi: 10.1063/1.4807702.
We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C(n)(-), n = 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C2 (-) molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s ± 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10(-14) mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.
我们报道了在斯德哥尔摩大学的双静电离子环实验（DESIREE）中首次实现离子束存储的情况。我们在溅射离子源中产生了原子碳阴离子束和小碳阴离子分子（C(n)(-)，n = 1、2、3、4）束。离子束被加速到10 keV的动能，并存储在一个置于13 K真空腔中的静电离子存储环中。对于10 keV的C2 (-)分子阴离子，我们使用两个独立的探测器系统测得残余气体限制下的束存储寿命为448 s ± 18 s。利用测得的存储寿命，我们估计残余气体压力在10(-14)毫巴范围内。当注入高电流离子束时，存储粒子的数量并不遵循单一指数衰减规律，而如果存储粒子仅因与残余气体碰撞时的电子脱离而损失，那么情况应是如此。相反，我们观察到初始衰减速率更快，我们将其归因于离子束的空间电荷对存储容量的影响。
