National Superconducting
Cyclotron Laboratory

Dave Morrissey
Dave Morrissey
University Distinguished Professor
Nuclear Chemistry
PhD, Chemistry, University of California, Berkeley 1978
Joined NSCL in September 1981
Phone (517) 908-7321
Fax (517) 353-5967
Office 1247-A
djm at

Dave Morrissey

Research in nuclear chemistry that is centered on the production and use of the most exotic, short-lived nuclei. We routinely apply this knowledge to produce beams of very exotic radioactive ions. These short-lived nuclei are interesting in their own right, some of which have not been observed before. My graduate students work on unrav­eling the mechanisms of nuclear reactions, on studying the decay properties of the most ex­otic nuclei, or on developing new techniques to separate, capture and control fast ions. The NSCL is a unique facility that brings together a strong group of nuclear scientists and pro­vides an exceptional setting for studying the properties of nuclei right on the MSU campus. The cyclotrons accelerate ions that span the periodic table to very high kinetic energies. When the fast ions react with a target nu­cleus, the incident ion is often broken into nuclear fragments with a distribution of sizes, some of which are very unstable and quite unusual. The probability distributions of the products were early subjects of study by my group and can be predicted with reasonable accuracy. We also showed that the momenta, or velocities, of the fragments are distributed around that of the beam and can be predicted by models of the nuclear reaction. These fast moving fragments can be passed through an isotope separator to produce beams of individual radioactive ions. We help to de­sign and develop these fragment separators, which have become the central instruments for research at the NSCL and the Facility for Rare Ion Beams (FRIB) under construction at MSU. The NSCL currently relies on its second generation fragment separator completed in 2001 while a revolutionary new fragment sep­arator is being designed for the FRIB facility that will replace the NSCL.

Along with using the new fragment separa­tor for production and decay studies, our group has completed the construction and development of an auxiliary device to slow down the exotic reaction products to thermal energies. In this project, we have extended the ion-guide ion-source (IGISOL) technique to collect individual radioactive ions. A he­lium-filled chamber is tailored to stop and collect the exotic isotopes produced by the A1900 fragment separator at NSCL using a differentially pumped gas-filled cell in a pro­cess related to atmospheric-sampling mass spectrometry. The so-called gas-catcher system was used in many successful and ex­tremely precise mass measurements at the NSCL carried out by the group headed by Prof. Bollen (MSU Physics). More recently the thermalized ions were used in collinear laser spectroscopy experiments, precision decay studies, and nuclear reaction studies. We are currently constructing a next-generation de­vice for thermalization of projectile fragments based on the concept of a reverse cyclotron that will be able to provide the large variety of fragments needed for mass measurements and other new experiments at the NSCL. The cyclotron-stopper is based on a four meter di­ameter superconducting magnet that weighs approximately 200 tons (see below).

Cyc stopper

Photograph of the gas-filled reverse-cyclotron during testing in 2014. The device relies on an inner 2 meter diameter beam chamber contained inside a 200 ton superconducting magnet. The particles will enter parallel to the floor from the right and be bent onto spiral paths by the magnetic field. They will slow down by collisions with helium gas and the thermalized ions will be extracted along the central axis.

Selected Publications

Extraction of Thermalized Projectile Fragments from a Large Volume Gas Cell, K. Cooper, C.S. Sumithrarachchi, D.J. Morrissey, A. Levand, J.A. Rodriguez, G. Savard, S. Schwarz, and B. Zabransky, Nucl. Instrum. Meth. A 2014, 763, 543.

Feasibility of Isotope Harvesting at a Projectile Fragmentation Facility: 67Cu, T. Mastren, A. Pen, G.F. Peaslee, N. Wozniak, S. Loveless, S. Essenmacher, L.G. Sobotka, D.J. Morrissey and S.E. Lapi, Nature/ Scientific Research 2014, 4, 6706.

The NSCL Cyclotron Gas Stopper - Under Construction, S. Schwarz, et al., Proc. EMIS Conf. 2012, Nucl. Instrum. Meth. B 2013, 317, 463.

Production cross sections from 82Se frag­mentation as indications of shell effects in neutron-rich isotopes close to the drip-line, O.B. Tarasov, M. Portillo, D.J. Morrissey, et al., Phys. Rev. C 2013, 87, 054612.

Evolution of the momentum distribution with mass loss in projectile fragmentation reactions, K. Meierbachtol, D.J. Morrissey, M. Mosby, and D. Bazin, Phys. Rev. C 2012, 85, 034608

Discovery of Exotic Isotopes 40Mg and 42Al Suggests Neutron Drip Line Slant Toward Heavier Nuclei, T. Baumann, et al., Nature 2007, 449, 1022.

Modern Nuclear Chemistry, W. Loveland, D.J. Morrissey and G.T. Seaborg (Wiley Interscience, 2006).

Radioactive Nuclear Beam Facilities Based on Projectile Fragmentation, D. J. Morrissey, and B. M. Sherrill, Proc. Royal Soc. A, 356. 1985 (1998), and Lecture Notes on Physics 2004, 651, 113.