Nuclear Physics Seminar: Annika Lennarz, TRIUMF, Canada


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Direct measurements of charged-particle induced reactions using rare isotope beams at TRIUMF

Annika Lennarz
TRIUMF, Canada

The study and understanding of the evolution and fate of the stars in the universe is one of the great challenges of modern astrophysics. We seek to understand the nuclear processes involved in stellar evolution, as their details give us insight into the fusion pathways and routes to the synthesis of heavy elements. The investigation of radiative capture reactions is crucial for the understanding of nucleosynthesis pathways in explosive stellar environments. However, direct measurements of their reaction cross sections at astrophysically relevant low energies are extremely challenging due to the vanishingly small cross sections in this energy regime. Additionally, many astrophysically important reactions involve radioactive isotopes, which pose challenges for beam production and background reduction.

To overcome these challenges, dedicated facilities, such as the DRAGON (Detector of Recoils And Gammas Of Nuclear reaction) recoil separator have been designed to experimentally determine nuclear reaction rates of interest for nuclear astrophysics via direct inverse kinematics measurements. To date, DRAGON still holds the record for the number of direct measurements of radiative capture reactions performed with radioactive ion beams world-wide and makes use of the high-intensity stable ion beams available at TRIUMF.

Further, nuclear (astro)physics research is conducted using the TRIUMF UK Detector Array (TUDA) facility at TRIUMF-ISAC. TUDA is a multipurpose, large solid angle and high granularity silicon detector array, detection chamber and instrumentation apparatus designed for charged particle detection. Similar to the DRAGON facility, the experimental program at TUDA covers a wide range of astrophysical scenarios, thereby investigating explosive as well as non-explosive nucleosynthesis environments. The scientific program at TUDA does not only address urgent questions regarding nucleosynthesis in stellar environments, but also nuclear structure aspects by combining experimental nuclear astrophysics research with recent efforts in ab-initio theory at TRIUMF.

In my presentation I will outline the achievements of the well-established nuclear astro-physics program at TRIUMF and elaborate on the challenges of a selection of successfully performed and future rare isotope beam experiments as well as the advantages and versatility of the employed facilities.

Hosted by Prof. Brodeur

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