Preparation and cooling of magnesium ion crystals for sympathetic cooling of highly charged ions in a Penning trap

In this work, laser-cooled ion crystals containing 1000 to 100000 singly charged magnesium ions (Mg+) were prepared in a Penning trap. The properties of the ion crystals and their structure displaying long-range ordering were analyzed by various non-destructive techniques. After creation of the Mg + ions in the form of ion bunches in an external source, the ions were injected into the Penning trap where their temperature was reduced by eight orders of magnitude within seconds using a combination of buffer gas cooling and Doppler laser cooling. The achieved temperatures in the millikelvin-regime were close to the theoretical Doppler-cooling limit and sufficiently low to induce the transition to a crystal phase exhibiting long-range ordering. The structure of these mesoscopic ion crystals is in agreement with a model describing the crystal as a set of planar shells. This allows for a derivation of properties such as the charge density or the temperature of the observed crystals. For the process of combined buffer-gas and Doppler laser cooling an analytical model has been developed, which explains the time development of the temperature and the fluorescence signal in agreement with the experimental results

Preparation and cooling of magnesium ion crystals for sympathetic cooling of highly charged ions in a Penning trap

In this work, laser-cooled ion crystals containing 1000 to 100000 singly charged magnesium ions (Mg+) were prepared in a Penning trap. The properties of the ion crystals and their structure displaying long-range ordering were analyzed by various non-destructive techniques. After creation of the Mg + ions in the form of ion bunches in an external source, the ions were injected into the Penning trap where their temperature was reduced by eight orders of magnitude within seconds using a combination of buffer gas cooling and Doppler laser cooling. The achieved temperatures in the millikelvin-regime were close to the theoretical Doppler-cooling limit and sufficiently low to induce the transition to a crystal phase exhibiting long-range ordering. The structure of these mesoscopic ion crystals is in agreement with a model describing the crystal as a set of planar shells. This allows for a derivation of properties such as the charge density or the temperature of the observed crystals. For the process of combined buffer-gas and Doppler laser cooling an analytical model has been developed, which explains the time development of the temperature and the fluorescence signal in agreement with the experimental results

Simulation studies of the laser ablation ion source at the SHIPTRAP setup

A gas-filled miniature Radio-Frequency Quadrupole (mini-RFQ) was recently implemented into the SHIPTRAP laser ablation ion source to thermalize the laser-ablated ions and thus improve production efficiency as well as sample preparation. This source provides reference ions of various elements for online experiments with the SHIPTRAP mass spectrometer. In addition, it can be used to provide long-lived rare and radioactive isotopes available only in small sample sizes for high-precision mass measurements or to study systematic uncertainties. The performance of the laser ablation ion source was simulated using the COMSOL Multiphysics modeling software package. These studies indicate that a revised mechanical geometry and an optimized RF field improve the performance significantly

High-precision mass measurement of neutron-rich 96Kr

International audienceWhile the nuclear deformation in the region around Z = 40 and N = 60 has been studied in great detail, the possible onset of nuclear deformation in the isotopic chain of krypton (Z = 36) is still a subject of controversy. Here, we present a high-precision mass measurement of the neutron-rich nuclide $^{96}$Kr, as measured by the Multiple-Reflection Time-of-Flight Mass Spectrometer (MR-TOF-MS) at TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN). A statistical method, based on a hyper-exponentially modified Gaussian, has been employed to model the data. As such, the uncertainty introduced by overlapping peaks from beam contaminants was reduced and the mass excess of $^{96}$Kr determined to be -53097(57)keV. The capability of the method has been confirmed with measurements of the stable isotopic pair $^{40}$Ar/$^{40}$Ca, in which a relative accuracy Δm/m of 3.5 ⋅ 10$^{− 8}$ and a mass resolving power of more than 400000 were achieved