Information on gross $\beta$-decay properties of neutron-rich noble gas isotopes ${}^{49,50}\mathrm{Ar}$ was obtained at the PSB-ISOLDE facility at CERN using isobaric selectivity achieved by the combination of a plasma ion source with a cooled transfer line and subsequent mass separation. A doubly charged beam was used in the case of ${}^{49}\mathrm{Ar}$ to suppress the corresponding multicharged background from heavier noble gas fission products. The comparison of the obtained data with results of quasiparticle random-phase approximation calculations indicates that the $N=28\mathrm{}$ shell is not disturbed significantly for neutron-rich Ar nuclei. The obtained results are useful for better understanding of the origin of the ${}^{48}\mathrm{Ca}{/}^{46}\mathrm{Ca}$ isotopic anomaly discovered in inclusions from the Allende meteorite.

• Received 18 February 2003

DOI:https://doi.org/10.1103/PhysRevC.67.054314