Speaker: Professor Remco Zegers

Michigan State University

                                  Experiments at NSCL and FRIB with rare isotope beams at high magnetic rigidities

Experiments with fast (~100 MeV/u and above) beams of rare isotopes are important for achieving key scientific objectives of the low-energy user community. Tremendous progress has been made in studies of nuclear structure, nuclear astrophysics and broader applications by performing experiments with the S800 magnetic spectrometer and Sweeper magnet at the National Superconducting Cyclotron Laboratory (NSCL), and similar devices at rare-isotope beam facilities that also use in-flight fragmentation to produce beams of rare isotopes.

Experiments with fast rare-isotope beams will also be key to the scientific program pursued a the Facility for Rare Isotope Beams (FRIB), which is currently under construction. However, the above-mentioned spectrometers have a maximum magnetic rigidity that is too low by up to a factor of two for achieving the optimum luminosity for  fast-beam experiments. Gains in luminosity of an order of magnitude can be achieved with a High Rigidity Spectrometer (HRS) and planning for such a device is in progress.

In the colloquium, the scientific and technical motivations for the HRS will be presented. As an example, I will focus on experiments that utilize charge-exchange  reactions to extract information about weak reactions (electron-capture and beta decay) rates for astrophysical simulations, for example of core-collapse supernovae.

The P/T colloquium website is: http://p25ext.lanl.gov/schedule.php?type=coll