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Barry Davids
604-222-7396
Group Member
Research Scientist - TRIUMF

Barry Davids graduated with a B.Sc. in Mathematics from the University of Chicago in 1993 and went on to complete a Ph.D. in Physics at Michigan State University. As a Ph.D. candidate, he studied the 7Be(p, γ)8B process that gives rise to most of the high-energy neutrinos emitted by the Sun. Knowledge of this process is crucial to our understanding of the solar neutrino problem. Barry performed studies to infer the astrophysical S factor of this reaction. Barry did post-doctoral work at the Kernfysisch Versneller Instituut, before coming to TRIUMF in 2003.

Barry is the project leader for EMMA (ElectroMagnetic Mass Analyser), a recoil mass spectrometer currently being developed for TRIUMF’s ISAC-II facility. When ISAC-II’s intense beams of exotic nuclei react with a target, EMMA will detect and analyze the reaction products. By studying nuclei at the edge of stability, researchers advance our knowledge of the structure of matter and of the force that holds the nucleus together. Barry is responsible for the conception, design, and funding of EMMA; commissioning of the detector is projected for 2011.

Barry also works on DSL (TRIUMF’s Doppler Shift Lifetimes facility), studying the 15O(α, γ)19Ne reaction. This reaction contributes to the ignition of x-ray bursts on accreting neutron stars. Using the Doppler shift attenuation method, Barry and his colleagues infer reaction rates of astrophysical processes like 15O(α, γ)19Ne by measuring the lifetimes of excited compound nuclei. Barry is the Chair of the TRIUMF Seminar Committee and the Nuclear Astrophysics Scientific Working Group at the Canadian Institute for Nuclear Physics. He sings bass in the Gallery Singers, an early music chamber choir.

Chris Ruiz
604-222-7666
Group Member
Research Scientist - TRIUMF

Chris Ruiz is the DRAGON Group Leader at TRIUMF.

He started out life as a 'wannabe' astronomer, studying a BSc(hons) in Astronomy and Astrophysics at the University of Edinburgh, taking classes up on Blackford Hill at the Edinburgh Royal Observatory. At the end of his undergraduate degree, Chris got his first taste of experimental nuclear physics through a laboratory project studying Bell's inequality and its ramifications for quantum physics, via a really neat experiment using radioactive sodium-22. From then on he was hooked, then taking a PhD with the Edinburgh Nuclear Physics Group, studying prospective indirect methods of obtaining the important 15O(a,g)19Ne stellar reaction rate at Louvain-la-Neuve in Belgium, and also the first post-accelerated radioactive beam experiment at ISAC: the resonant elastic scattering of sodium-22 on protons - requiring development of a multi-channel R-matrix code.

Chris then joined the DRAGON group as a Post-Doc in 2003, eventually leading the 26Al(p,g)27Si measurement. After a short stint as a Post-Doc with the University of York Nuclear Physics Group, heading the TRIUMF side of the development of the SHARC silicon barrel array, Chris was hired as a TRIUMF Board-Appointed Research Scientist in order to head the DRAGON Group in 2007. Since then, Chris has been actively involved in shaping nuclear astrophysics research at the lab along with his colleagues. In addition to the DRAGON project, Chris currently spends time also on the NEURAL project, as well as the TUDA facility. Chris is the project leader for the ISAC Implantation Station, a facility that will allow the preparation of high-quality long-lived radioactive targets for use in charged-particle induced and neutron induced reaction experiments.

Chris is currently the Past Chair of the TRIUMF Users Group Executive Committee, as well as head of the TRIUMF Undergraduate Student Scholarship program.

Chris enjoys snowboarding, playing classical, folk and rock guitar, rock climbing, scuba diving, and attempting to cultivate an organic garden. He is also a motorcycle enthusiast and enjoys long rides deep into B.C. on his Yamaha FZ6. 

Falk Herwig
250-721-7743
Group Member
University of Victoria

Falk Herwig is an associate professor in the Dept. of Physics of Astronomy at the University of Victoria, BC. He obtained is PhD at the Astrophysikalisches Institut Potsdam and University Kiel in Germany and held post-doctoral positions in Potsdam (Universtiy), Victoria, and Los Alamos National Laboratory, Los Alamos, NM. Before coming back to BC in 2008 he held a Lecturer faculty position at Keele University, England.

Herwig's research interests are in the simulation of the origin of the elements in stars and stellar explosions. He has worked extensively on the evolution of stars, in particular of low- and intermediate mass, white dwarfs, binary stars and their interactions, as well as the nucleosynthesis in all of these. Herwig is enthusiastic supporter of the MESA stellar evolution code and presently helps with its stewardship. He is a founding member of the NuGrid collaboration.

Another focus of his research are large-scale simulations of the hydrodynamical mixing processes in the interior of stars, that relate to the nuclear production site of the elements. In this work he combines his experience stellar research with the powerful computational tools of Paul Woodward from the University of Minnesota.

In order to analyse the nucleosynthetic signatures of various types of stars Herwig has helped to create the NuGrid collaboration (http://nugrid.phys.uvic.ca) which produces codes and data sets relating to simulations of the origin of the elements. These codes allow a comprehensive analysis of the effect of individual nuclear reaction rates in a realistic simulation framework of real stars and stellar explosions. For example the inset figure shows the abundances of some key heavy elements that belong to the slow neutron capture process nucleosynthesis according to a NuGrid simulation of the interior of a 2 solar mass star.The NuGrid tools will be used extensively in the Canadian Center for Nuclear Astrophysics.

 

 

 

Lothar Buchmann
604-222-7403
Group Member
Senior Research Scientist - TRIUMF

Lothar Buchmann gained his diploma (`master') in 1979 and his PhD in 1984 at the University of Münster within the astrophysics group of Prof. Claus Rolfs. His PhD thesis was the first study of the 26Al(p,gamma)27Si reaction rate at stellar energies and beyond. Lothar then came to TRIUMF as a joint research associate with the University of Toronto in the group of Dick Azuma. His posdoc experience included work on the MR-spectrometer, pion scattering and building the TISOL isotope seperator. In 1988 Lothar became a TRIUMF Research Scientist and became involved in the development of a continuous wave, optically pumped ion source at TRIUMF, and in addition, a nuclear polarimeter for low proton energies usable both at the optically and the Lambshift polarized ion sources based on the 6Li(p,3He)a reaction. 

From 1989-2000 Lothar worked at the TISOL isotope separator which continued and resulted in the transition of the separator from a test facility to a facility being able to perform physics experiments. This transition began in the summer of 1989 when the first ECR source at an isotope on-line separator became operational. Using the TISOL facility, Lothar was the principal investigator of a 16N-decay study employing the ECR source. This study led to the placement of significant restrictions on the low energy p-wave (E1-capture) part of the 12C(alpha,gamma)16O reaction, which dominates the rate at the energies associated with quiescent helium burning in Red Giants. This so called 'TRIUMF-Red Giant' experiment received much press around the world, and is still considered a landmark measurement in the understanding of stellar evolution. The experiment let Lothar to put his nose into low energy scattering theory for which he developed many programs. His expertise has been extended to many other reactions now.

Lothar was one of the principal investigators of a 7Be(p,gamma)8B study, important in the context of the solar neutrino problem and the new generation of solar neutrino detectors. Lothar led the efforts to prepare a 7Be target (in collaboration with the University of Washington together with K. Snover and A. Adelberger). The target part led to the production of a small size metallic 7Be target where the 7Be was produced at a 13 MeV (TR13) cyclotron at TRIUMF employing a liquid 7Li target. The joint TRIUMF-University of Washington measurement of this reaction is considered one of the best determinations of the reaction rate. 

Lothar was a crucial member in the team that steered the specifications for the ISAC facility and instrumentation to ISAC, like DRAGON. He was involved in some of the experiments therein including the TUDA and DRAGON facilities.

At present, Lothar is involved in the deevelopment of two time projection chambers: TACTIC for detecting recoil particles from particle reactions at low velocities and NEURAL, a detector for neutron induced charged particle detections.