Grant: Subatomic Physics Envelope - Project

Fast beam, collinear laser spectroscopy has long been seen as a highly sensitive method with which to probe nuclear structure of ground and long lived isomeric states. When coupled to radioactive beam facilities that are capable of producing long chains of isotopes of many chemical elements these techniques can provide invaluable information on the evolution of nuclear structure from stability out to the drip lines. The use of high resolution laser spectroscopy of the atomic electrons, which in turn directly probe the nucleus, leads to a non-destructive, highly sensitive probe that can extract subtle nuclear effects in a largely model independent way. In general these methods allow for the unambiguous determination of the nuclear spin, magnetic dipole and electric quadrupole moments along with the changes in the RMS charge radii along a nuclear chain. In certain cases it is also possible to extract higher order affects such as the nuclear magnetisation distribution, magnetic octupole moments and the absolute RMS charge radii. As such the results from this work has far reaching impact across many areas of nuclear physics ranging from nuclear structure through weak nucleon-nucleon interactions to fundamental symmetry tests of the standard model. This proposal aims to continue the project that has been ongoing for several years at the ISAC facility at TRIUMF. Utilising a combination of the rare isotope beams available as well existing infrastructure makes for a system that is has unique capabilities. For example the continuing use of Titan's radio frequency quadrupole buncher to convert the continuous ISAC beam into short bunches with properties that are independent of the ion source that produced them has led to an increase in sensitivity of over 3 orders of magnitude over traditional systems. Ongoing technical development on both the methods of data-acquisition as well as laser and atomic manipulation, which forms part of this proposal, has already led to further increases in sensitivity and are currently being replicated at most facilities around the world. The versatility of the technique is shown by the range of isotopes and nuclear properties that it is proposed to study. In the vicinity of 32 Na it is proposed to measure ground state properties of very neutron rich Al, Mg and Na isotopes in order to better understand the nuclear structure of this region as well as investigate the possibility of the existence of long lived isomeric states. In contrast measurements of the ground and isomeric states in light Pb and Fr isotopes will not only further enhance our general knowledge of this region but could also be used to investigate the specific changes in the distribution of magnetism within the nucleus across this region of the nuclear chart.