Speaker
Description
The AEgIS experiment aims at measuring the gravitational acceleration of antihydrogen ($\bar{\hbox{H}}$). A key limitation is the $\bar{\hbox{H}}$ temperature because the thermal motion blurs the $\bar{\hbox{H}}$ free-fall trajectories. Sympathetic cooling of antiprotons by co-trapped laser-cooled negative ions would enable synthesis of $\bar{\hbox{H}}$ at mK temperatures -- three to four orders of magnitude below the currently achieved ones. Laser cooling of anions, however, has not yet been achieved. We aim at realizing Doppler laser cooling of C$_2^-$ ions. We have produced, mass-selected and trapped C$_2^-$. Currently, the capture efficiency of the trap and the lifetime of trapped C$_2^-$ ions are improved and in-beam spectroscopic studies of C$_2^-$ are prepared.
