TY - GEN Y1 - 2021/// ID - heidok30105 AV - public UR - https://archiv.ub.uni-heidelberg.de/volltextserver/30105/ CY - Heidelberg N2 - This thesis presents two anion cooling techniques based on their interaction with photons or ultracold atoms, pushing the frontier of anion cooling beyond state-of-the-art experiments. A hybrid atom-ion trap (HAITrap) is presented, combining an octupole radio frequency (rf) trap and a dark spontaneous-force optical trap for rubidium. The anions and atoms are probed via photodetachment tomography, time-of-flight thermometry and saturation absorption imaging, respectively. The anion photodetachment via a focused far-threshold laser beam removes anions selectively by their energy. This thesis reports forced evaporative cooling of OH? via dynamically moving the beam, below 4 Kelvin in 2 seconds. A derived thermodynamic model describes the evolution of anion temperature and number, including the importance of ion-ion thermalization and resulting rf-heating in such traps. It shows experimental and theoretical framework to prepare any anionic specie in a vast energy range. This thesis also reports the sympathetic cooling and the collision dynamics of anions with ultracold rubidium in a HAITrap. The cooling is experimentally demonstrated to 30(2) Kelvin for O? and 135(8) Kelvin for OH?. The different cooling behavior is explained by their dissimilar loss channels, which are identified and quantified. These limitations can be overcome in future experiments, providing a tool to cool anions translationally and internally. TI - New approaches for cooling molecular anions to the Kelvin range A1 - Tauch, Jonas ER -