Fundamental Physics - Subatomic Physics

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	Fundamental Physics » Research » Subatomic Physics

Subatomic Physics

The Subatomic Physics Group at Chalmers University of Technology and Göteborg University conducts a broad programme for studies of exotic nuclei in the vicinity of the neutron and proton driplines. Very large beta-decay energies and low separation energies for particles, or cluster of particles characterize such nuclei. These features result in unusual phenomena and the exotic nuclei are in general characterized by beta-delayed particle decay modes. The Göteborg Group was first to observe (b2n), (b3n), (bt) and (bd) emission in light neutron rich nuclei produced at the ISOLDE Facility at CERN. The latter decay mode is only present in nuclei with a developed halo structure, a phenomenon also first suggested by the Göteborg Group.

In combination with the experimental programme there is a vital theory activity in Göteborg led by Prof. Mikhail Zhukov. The theoretical activity is closely related to the experimental programme but direct basic theoretical research is also done concerning few-body systems in different models - both numerical, with large computer codes, and analytical.

The present experimental programme is conducted at the ISOLDE PSB Facility at CERN, the heavy-ion accelerator GANIL at Caen and the heavy-ion accelerator SIS at GSI. The ISOLDE PSB Facility started in 1992 and is now in full operation with both the GPS and the HRS separators on-line. The new REX ISOLDE accelerator, aiming at postacceleration of ions produced at ISOLDE PSB (more than 70 elements are available at present) was successfully put into operation in November 2001. At GANIL our programme is mainly connected to radioactive beams in the energy range 25-45 MeV/u separated out with the fragment separator LISE3. The SPIRAL Facility that will come into operation at the end of this year will provide medium-energy beams that will be an interesting complement to REX ISOLDE. The energy range at GSI is 200 MeV to 1 GeV/nucleon. There are two different experimental setups, which we use at GSI. The ALADIN-LAND setup is a combination of wire and drift chambers around the target placed directly in front of the large dipole magnet ALADIN, which is used to analyze the charged fragments after breakup reactions. Further downstream the neutron detector LAND is placed. The combination gives a setup capable to give complete kinematics information. At the FRS the target is placed in the mid-focus of the spectrometer and gamma detectors are placed around. The charged breakup fragments are detected with a so-called MUSIC chamber at the final focus of the machine. The combined studies at these three Facilities give us a unique chance to get broad information about the nuclear structure at the driplines.

Our main working partners in this work are from Aarhus University in Denmark, from Instituto de Estructura de la Materia, CSIC; Madrid, Spain and from ISOLDE and GANIL. The work in Göteborg is divided into detector development, data reduction and analysis combined with theoretical investigations, both in direct relation to the available experimental data and for the planning of new experiments.

www.fy.chalmers.se
www.chalmers.se


	Fundamental Physics Chalmers Univ. of Technology 412 96 Göteborg Visiting address: Origogården 1; Fysikgränd 3 Tel 031-772 3260 \| Fax 031-772 3204 / 3269

Questions/comments:
martin.cederwall@chalmers.se