Precision mass measurements of some isotopes of tungsten and mercury for an adjustment to the mass table in the region A=184 to A=204
Barillari, Domenico K.
This thesis concerns the precise re-measurement of mass value in the region of the mercury isotopes, such that important discrepancies in the high-mass end of the mass table could be resolved. 'Scope and contents'. Four mass spectroscopic doublets involving a comparison between 201Hg, 199Hg and 183W (and using a chlorocarbon reference) are reported from measurements made with the upgraded Manitoba 11 deflection instrument. The measurements address the problem of a mass table mis-adjustment in the region of the valley of B-stability between the tungsten group and the noble metals. The results, forming a well-closed loop of mass differences, support the earlier results of Kozier [Ko(1977)] regarding the (stable) mercury isotope masses and confirm an approximate 20 [mu]u discrepancy in the mass adjustment of Audi 'et al' [Au(1993)]. A local least-square re-adjustment conducted using these and existing mass table data suggests that the error originates with mass differences pertaining to one or more other nuclide pairs, perhaps 193Ir-192Ir. The work on upgrading the precision voltage supply and potentiometry system of the Manitoba II instrument is also reported, as is a new assessment on the data processing method. (Abstract shortened by UMI.)