Jirina Stone

Abstract:

The systematics of energy ratios of successive levels of collective bands in medium- and heavy-mass even-even nuclei are studied. A measure of their deviation from the vibrational and rotational limiting values is found to have different magnitude and angular momentum dependence in the vibrational, -unstable and rotational regions. The usefulness of this new criterion for distinguishing between different kinds of collective behavior is demonstrated in the case of intruder and octupole bands. © 1991 The American Physical Society.

Abstract:

A facility for Nuclear Implantation into Cold On-Line Equipment (NICOLE) is being installed at the new on-line isotope separator ISOLDE 3 at CERN. The first on-line run was in the beginning of July 1988. The low temperature equipment has been successfully tested and first off-line experiments on various isotopes have been performed. NMR/ON has been done on vaious isotopes (Co, Xe, Pt, Au) in iron host. First experience with the top-loading dilution refrigertor (Oxford Instruments Limited) shows that it performs very well. The cooling power is 400 μW at 100 mK and 34 μW at 25 mK. The base temperature can be kept continuously well below 5 mK. NMR/ON can be performed at temperatures below 5.5 mK. The base temperature on-line is expected to be lower then 6 mK. The sample can be cooled down from room temperature to 10 mK within two hours, to 6 mK within 3 hours which is not only important for off-line but also for on-line experiments when samples have to be changed to remove long lived daughter activity. The latest results will be reported. © 1998 J.C. Baltzer A.G., Scientific Publishing Company.

Abstract:

The introduction very briefly outlines the basic idea and experimental evidence to suggest that quarks may behave differently in nuclei and in indididual nucleons, with possible consequences for the calculation of nuclear magnetic dipole moments. After description of a calculation of moments made using the extreme model of total quark deconfinement (the MIT bag model) attention is focussed on experimental tests and the state of current evidence for more partial quark deconfinement. The arguments of Yamazaki which give an experimental basis for distinguishing quark deconfinement effects from, specifically, effects caused by pion echange currents, are given in more detail. The reasons underlying choice of nuclei in which meaningful tests may be possible are given. Early claims by Karl et al. to have demonstrated the existence of quark deconfinement in mass 3 nuclei are discussed. The current status of evidence for deconfinement based on orbital gfactor measurements in heavier nuclei is also summarised. Finally some examples are given of possible experiments using recently developed on-line facilities which may provide further tests of these ideas. © 1998 J.C. Baltzer A.G., Scientific Publishing Company.