Masses forAr43and the new isotopesAr

Abstract

The reactions (n,~Be), (n, Be), and (Li, SB) on +Ca at E(n)=78 MeV and E( Li)=80 MeV were used to determine the mass excesses of 3Ar (-31. 98+ 0.07 MeV}, 4~Ar(-29.727 + 0.06 MeV}, and 48Ar (-29.732+ 0.07 MeV} by counter telescope techniques. Excited states in 4~Ar at 1.74+0.05, 2.55+0.05, 3.56+0.07, and 4.74+0.10 MeV and in 45Ar at 1.66+0.05, 2.42+0.05, and 3.25+ 0.07 MeV were also observed. Comparisons are made with mass predictions calculated from simple mass relations based on the shell model and with those obtained from the Garvey and Kelson approach. NUCLEAR REACTIONB~Ca(n, 'Be), {a 'Be) a=78 MeV; 8Ca( Li 'B) E=80

Reaching the limits of nuclear stability

“…The mass measurement of 41 Si [216] corresponds to a negative one-neutron separation energy of −20 ± 1930 keV [105]. Although this value is consistent with the observation that 41 Si is bound [200], one would expect 43 Si to be unbound (−190 ± 860 keV, [105]). However, 43 Si is also bound [214].…”

“…The use of more complicated multiparticle transfer reactions lead to the first observation of the proton dripline nuclei 9 C, 20 Mg, and 22 Al by means of the reactions 12 C( 3 He, 6 He) 9 43 Cl [44].…”

“…The dripline for odd-N nuclei has experimentally unambiguously been determined up to N = 27. The heaviest observed dripline nucleus up to date is probably 43 Si or maybe even 46 P. For even-N nuclei the location of the dripline has not been established beyond N = 20 although it is very unlikely that 30 O could be bound. Table 7 lists the bound and unbound isotones for 20 < N 36.…”

Masses of62Fe and the new isotope68Ni from (18O20Ne) reactions

“…Earlier mass measurements for neutron rich nuclei with light ion induced reactions (see for example Refs. 8,17) as well as the (1sO, ZONe) reaction using counter telescopes, have led to possible errors of typically > 50 keV dominated essentially by relatively poor statistics. We have shown that by profiting from the large (lsO, 2~ cross sections at small angles, one obtains precise mass values where the statistical errors are no longer the limiting factors.…”

β decay ofS40,42andCl43Winger1, Mantica2, Ronningen3 2006Phys. Rev. C27191View full textAdd to dashboardCite

“…Hence, the β decay is populating a different set of lower-spin states than those populated by the heavy-ion reaction. For 43 Ar, four excited states were observed by Jelley et al using the 48 Ca(α, 9 Be) 43 Ar reaction [12], whereas Maréchal et al used inelastic proton scattering with a radioactive 43 Ar beam to identify a separate state [13]. Only the state at 1.74 ± 0.05 MeV has a possible corresponding state to those previously observed in β decay [8].…”