Direct mass measurements in the light neutron-rich region using a combined energy and time-of-flight technique

Abstract

Historically, masses have been determined one at a time via decay or reaction Q-value measurements. In general only after several such individual measurements could one establish a trend in the binding energies and thus develop an improved understanding of the nuclear mass surface. With the advancement of online mass spectrometers, it became possible to measure long isotopic sequences. Although only alkali elements have been extensively measured to date, this technique has proved successful in revealing sudden changes in nuclear structure and in pointing out systematic deficiencies of various mass models. In the experiment described herein, we have worked to extend mass measurement capabilities one step further with the development of a more general approach in which a whole series of nuclei can be measured simultaneously, independent of their N or Z. Below we demonstrate that direct mass measurements can be performed for fast recoiling nuclei using a combined energy and time-of-flight (i.e., M proportional to ET/sup 2/) technique.