There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

The performance of the Pulse-Shape Analysis (PSA) in AGATA HPGe detectors was investigated and improved employing a \\($\backslashgamma\$\)\($\gamma$\)-ray source measurement based on \\($ e^\+\e^\-\\$\)e+e-annihilation radiation after decays of 22Na by \\($ \backslashbeta^\+\\$\)\($\beta$\)+decay. The first interaction positions of the two 511keV \\($\backslashgamma\$\)\($\gamma$\)rays were determined and the connecting line of these two positions was compared to the known source position as a measure for the PSA performance. The position resolution and its dependence on the PSA parameters were investigated by varying most relevant input quantities: the charge carrier mobility of the holes, the response of the employed measuring electronics especially the preamplifier rise time. The relative statistical weight of charge signals and transient signals was scrutinized. The optimal distance metric of the grid-search algorithm and its impact on the position resolution were determined.