Dr AJ Mitchell

Mitchell, AJ profile
Position Senior Fellow
Department Nuclear Physics & Accelerator Applications
Research group Nuclear structure group
Office phone (02) 612 53526
Email
Office Nuclear Physics 2 53

Measuring and modelling free-ion hyperfine fields

Motivated by exciting prospects for measurements of the magnetism of rare isotopes produced by the new radioactive beam accelerators internationally, this experimental and computational project seeks to understand the enormous magnetic fields produced at the nucleus of highly charged ions by their atomic electron configuration.

Emeritus Professor Andrew Stuchbery, Emeritus Professor Tibor Kibedi, Dr Brendan McCormick, Dr AJ Mitchell

Measuring electric quadrupole moments - the shapes of atomic nuclei

New methods to determine the shapes of atomic nuclei via the measurement of their electric quadrupole moment are being developed. Most nuclei are prolate spheroids - shaped like an Australian Rules football. As well as giving a picture of the nucleus, the quadrupole moment is an important observable to test theory. 

Emeritus Professor Andrew Stuchbery, Dr AJ Mitchell, Professor Gregory Lane, Dr Brendan McCormick

Ultra-fast lifetime measurements of nuclear excited states

Atomic nuclei can behave as collections of individual particles or as strongly collective quantum systems. This project uses precision gamma-ray spectroscopy and ultra-fast lifetime measurements to investigate how and why these behaviours emerge, providing new insights into nuclear structure and the forces that govern atomic nuclei.

Professor Gregory Lane, Dr AJ Mitchell, Emeritus Professor Andrew Stuchbery

Nuclear lifetimes - developing new apparatus and methods

The measurement of the lifetimes of excited nuclear states is foundational for understanding nuclear excitations. This project covers three measurement methods that together span the nuclear lifetime range from about 100 femtoseconds to many nanoseconds. The project can include equipment development, measurement, and the development of analysis methodology (programming and computation). 

Emeritus Professor Andrew Stuchbery, Dr AJ Mitchell, Professor Gregory Lane, Dr Brendan McCormick

Exploring atomic nuclei at the limits of their existence

Some atomic nuclei are so neutron-rich that they survive for only fractions of a second before decaying. This project uses beta decay and gamma-ray spectroscopy to study these rare systems, revealing how nuclei behave at the limits of existence and how heavy elements are created in stellar explosions.

Dr AJ Mitchell, Professor Gregory Lane

Nuclear magnetism - magnetic moment measurements

This project builds on our established track record of developing novel methods to measure magnetic moments of picosecond-lived excited states in atomic nuclei, and the theoretical interpretation of those measurements. Students will help establish new methodologies to underpin future international research at the world's leading radioactive beam laboratories.

Emeritus Professor Andrew Stuchbery, Dr AJ Mitchell, Professor Gregory Lane, Dr Brendan McCormick

Are atomic nuclei losing their 'magic'? Experimental tests of the Nuclear Shell Model

The Nuclear Shell Model has shaped our understanding of atomic nuclei for more than 75 years, yet recent experiments challenge some of its key predictions. This project uses particle-transfer reactions and the Enge Magnetic Spectrometer to probe nuclear structure, giving students hands-on experience with experiments, instrumentation, and data analysis.

Dr AJ Mitchell, Professor Gregory Lane, Emeritus Professor Andrew Stuchbery

Rewriting the nuclear physics textbooks: Testing the Vibrational Model of atomic nuclei

For decades, many excited states in atomic nuclei have been interpreted as surface vibrations. New experimental evidence suggests this picture may be incomplete. This project uses Coulomb excitation and transfer reactions to investigate nuclear shapes and collective motion, helping to test ideas that underpin modern descriptions of atomic nuclei.

Dr AJ Mitchell, Emeritus Professor Andrew Stuchbery, Professor Gregory Lane