Exotic Nuclei - AG Nörtershäuser

Exotic Nuclei

Nuclear Chart with Laser Spectroscopy
Nuclear Chart with Laser Spectroscopy

The atomic spectrum contains information about the properties and structure of the nucleus. Resonances of different isotopes appear for example at slightly different frequencies due to redistribution of the nuclear charge, i.e. the protons, when additional neutrons are added. The charge radius of nuclei can be extracted from these shifts. Moreover, an additional splitting of resonance lines, – the hyperfine structure – allows the determination of the nucleus’ spin, its magnetic moments and about its deformation. Measuring these properties along a chain of isotopes allows us to understand the interactions among the constituents of the nucleus. Such experiments become very challenging when it comes to isotopes far away from the valley of β-stability, where nuclei can be produced only in minute quantities and their lifetime is reduced to only a few milliseconds. Collinear laser spectroscopy is an established tool to study these properties and several detection techniques have been adopted during the last decades to increase accuracy and sensitivity in order to explore more and more exotic regions of the nuclear chart. Currently we apply or plan collinear laser spectroscopy at the following facilities in cooperation with international partners.

COLLAPS @ ISOLDE (CERN)

COLLAPS Collaboration Meeting 2018
COLLAPS Collaboration Meeting 2018

ISOLDE is an isotope production facility at Europe’s largest accelerator laboratory CERN. It is one of the world’s leading facility in producing short-lived isotopes at low energies as they are required for collinear laser spectroscopy The COLLAPS setup, installed in the experimental hall at ISOLDE, is the “senior” of such experiments and, nevertheless, still one of the most productive’s of its kind. Operation is expected to start again soon, after the 1,5-years shutdown of ISOLDE, once the installation of our new laser laboratory is finished. Stay tuned to learn about new results from there ….
COLLAPS is a collaboration oft the MPIK in Heidelberg, the Johannes Gutenberg University in Mainz, the TU Darmstadt and the KU Leuven. The local team at CERN currently consists of the following persons: Dr. Hanne Heylen, Dr. Mark Bissel, Dr. Stephan Ettenauer, Dr. Magdalena Kowalska, Dr. Ronald Garcia-Ruiz and Dr. Xiaofei Yang.

Argonne National Laboratory @ Argonne

Expected production rates at CARIBU (taken from http://www.phy.anl.gov/atlas/caribu/ATLAS_Cf_upgrade.pdf)
Expected production rates at CARIBU (taken from http://www.phy.anl.gov/atlas/caribu/ATLAS_Cf_upgrade.pdf)

At the Argonne National Laboratory (ANL) we plan experiments at the ATLAS accelerator as well as at the new CARIBU facility. A new collinear laser spectroscopy beamline will be established in collaboration with the working group of Peter Müller in the Low Energy Group at ANL. The goal is to determine the nuclear charge radius of the proton-halo nucleus boron-8 at the ATLAS facility and to perform collinear laser spectroscopy on short-lived fission products of Californium-249 at CARIBU.
These projects have been initiated in the frame of the new Collaborative research Centre (Sonderforschungsbereich) SFB 1245 and are supported by DFG.

BECOLA @ NSCL

Im Rahmen des SFB 1245 engagieren wir uns auch am BECOLA Experiment (BEam COoler and LAser spectroscopy facility) am National Superconducting Cyclotron Laboratory. Hier gibt es bereits eine langjährige Zusammenarbeit, die in den kommenden Jahren intensiviert werden soll. So sind wir beispielsweise in den Aufbau eines neuen Fluoreszensnachweises an BECOLA involviert, mit dem die Nachweiseffizienz insbesondere bei der Spektroskopie an Ionen gesteigert werden soll. Ein erster Einsatz ist für den Sommer 2017 geplant.