Spontaneous fission

The Dr. Westmeier GmbH has had a long association with the Institute for Nuclear Chemistry in the Department of Chemistry, University of Marburg.

Dr. Wolfram Westmeier carried out his doctoral work (1975-1981) under the supervision of Prof. Paul Patzelt. His project was carried out at CERN and involved the determination of cross-sections for spallation products from the reaction of 600MeV protons with Th-232. It was then that he began his work to develop the ultimate program for the analysis of alpha spectra. He developed the megaprogrammes for alpha spectrum unfolding ALFWHM and ALFUN and used these to analyse the extremely complex alpha spectra from the radioactive reaction products. This work was the basis for his simplier and much more easy to use software ALPS. His was one of the first works that gave a complete mass distribution for the spallation products from proton induced reactions on a heavy target.

He later supervised the work of other doctoral and masters students in the Institute of Nuclear Chemistry in Marburg. Two that are of particular interest here are the works of Dr. Jan van Aarle and Dr. Klaus Siemon who is now a member of the Dr. Westmeier GmbH team. Both works involved the identification and measurement of the mass and energy distribution of the fission fragments from the spontaneous fission of Md-260, Cf-252 (van Aarle) and Fm-257 and Cf-252 (Siemon).

Dr. Jan van Aarle did his work (1986-1992) on only 3000 atoms !! of Md-260 and he unambiguously proved the co-existence of different exit channels in spontaneous fission reactions. The Md-260 was produced in the reaction of 126 MeV Ne-22 on an Es-254 target at the 88-inch cyclotron of the Lawrence Berkeley Laboratory, Berkeley, California. Chemical separation of Md was performed in Lawrence Livermore Lab by the group of Prof. Ken Hulet.

Dr. Klaus Siemon´s work (1991-1997) brought technical improvements to the measuring systems thus enabling him to extend the former experiments with Cf-252 and then to tackle Fm-257 where the non-standard exit channel for spontaneous fission is less pronounced. His thesis is available as a .PDF file. Dr. Siemon joined the Dr. Westmeier GmbH in 1998.

Dr. Hilary Westmeier (formerly Robotham) did her doctoral work (on fast reaction kinetics) with Prof. Gerald C. Lalor, former Pro-Vice-Chancellor of the University of the West Indies. She was appointed the first Coordinator of the newly founded Centre for Nuclear Sciences in 1983. She was responsible for the administration of the Centre under the Directorship of Prof. Lalor, and supervised the Centre´s projects in environmental measurements using nuclear and related analytical techniques. She was a licensed Reactor Operator I for the Canadian SLOWPOKE research reactor. During her time at the Centre (1983-1993), she set up the first Jamaican Personnel Monitoring Service for radiation workers in Jamaica. The Centre for Nuclear Sciences at the University of the West Indies was named an International “Centre of Excellence” in 1995 and is now the International Centre for Environmental and Nuclear Sciences.
Dr. H. Westmeier joined the Dr. Westmeier GmbH in 1994.