Nuclear Physics Seminar: Lauren Callahan and Austin Nelson, University of Notre Dame

The MONICA Detector and Future Plans for AMS at AGFA

Lauren Callahan
Graduate Student, University of Notre Dame

Experimentalists in the field of Accelerator Mass Spectrometry (AMS) are constantly looking for ways to separate higher mass isobars to better understand the origins of the universe. Through the use of the Argonne Gas-Filled Analyzer (AGFA) and Argonne National Lab (ANL), these AMS measurements have a better chance of success due to the high energies achieved by the accelerator at ANL and AGFA’s higher magnetic rigidity. To aid in the success of AMS at AGFA, a new detector, the Multi-anOde Nuclear Ionization Chamber at Argonne (MONICA) was constructed at the Hebrew University of Jerusalem and commissioned at the Notre Dame Nuclear Science Lab. A previous AGFA experiment providing proof of concept for an AMS experiment, commissioning measurements of the MONICA detector, and future plans for the detector will be discussed.

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In-Cathode Activations for ⁴¹Ca Production Cross Section Measurements

Austin Nelson
Graduate Student, University of Notre Dame

⁴¹Ca (t_1/2 = 9.94 x 10⁴ yrs) is an important stellar radionuclide and its production in the early Solar System can help determine the viability of models of early stellar processes. Information on the production of ⁴¹Ca is limited as several production cross sections have minimal or no experimental data. A different reaction technique has been under development and will be tested at the Nuclear Science Lab at the University of Notre Dame. This technique utilizes an in-cathode reaction method, which means that the target material is pre-packed into an ion source sample holder (cathode) and is then irradiated. The activated sample is then placed directly into the ion source to be sputtered and measured using Accelerator Mass Spectrometry. This method completely bypasses the chemistry steps that would be necessary with other reaction activation techniques. We will report our initial findings and the viability of this method using the reaction ⁴⁰Ca(³He, 2p)⁴¹Ca, which already has experimental cross section data that agrees well with Talys predictions.

Hosted by Prof. Wiescher

All interested persons are invited to attend remotely—email physics@nd.edu for information.