DESIREE: Physics with cold stored ion beams

Abstract

Abstract. Here we will briefly describe the commissioning of the Double ElectroStatic Ion Ring ExpEriment (DESIREE) facility at Stockholm University, Sweden. This device uses purely electrostatic focussing and deflection elements and allows ion beams of opposite charge to be confined under extreme high vacuum and cryogenic conditions in separate "rings" and then merged over a common straight section. This apparatus allows for studies of interactions between cations and anions at very low and well-defined centre-of-mass energies (down to a few meV) and at very low internal temperatures (down to a few K).

Considerable matrix shift in the electronic transitions of helium-solvated cesium dimer cation Cs2He+n

“… 31 – 33 In combination with theory, the experimental results of the matrix shift as well as the width of the absorption lines provide unprecedented insight into the details of the solvation of ions with helium, including phase transitions and isomeric effects. Alkali metal atoms reside on dimples at the surface of helium droplets, as shown in numerous experimental 21 , 34 – 40 and theoretical studies. 41 – 46 Alkali metal clusters, however, are submerged into the cluster above a critical cluster size.…”

Simultaneous electrostatic trapping of merged cation & anion beams

“…3,37,51,52 Until this work, the double electrostatic ion ring experiment (DESIREE) was the only experimental setup that combines ion-trapping with a merged-beam section of velocity matched fast cation and anion beams. 19,53,54 In contrast to storage-ring devices, the electrostatic ion beam trap (EIBT) uses electrostatic mirrors to reflect and focus a fast ion beam in an analogous geometry to an optical resonator. 55,56 The EIBT technology has been implemented in a broad range of electrostatic trapping applications.…”