Alpha decay of new neutron deficient gold, mercury, and thallium isotopes

Abstract

In fusion evaporation reactions of a 92Mo beam with targets of neutron deficient Rb -Mo isotopes very neutron deficient isotopes of elements between Au and Po have been produced. The new isotopes 173,174Au ' 175,176Hg ' and 179T1 were identified by alpha spectroscopy. The mass excess value of 176Hg could be linked to known values of the N-Z= 16 chain. The location of the new isotopes with respect to the proton drip line is discussed. A new high energy e transition of (7.20 _+ 0.02) MeV and T~/2=(1.4 _+0.5)ms has been found in the reaction 92Mo+89Y ~ ~81T1" at an excitation energy of 37 MeV. It is tentatively assigned to isotopes produced in 2-particle evaporation channels.

β-delayed fission andαdecay of178Tl

“…The observed energy is in a good agreement with the values of 6547 keV from Ref. [11] and 6538(13) from previous works [10,12,13].…”

“…The α decay of the daughter isotope 174 Au was previously investigated in the works [10][11][12][13]. The most recent work [11] proposed the existence of two α-decaying isomeric states in this nucleus; see Sec.…”

“…[10][11][12][13]. In particular, in the same study of 178 T la tt h eB G F S [ 10], a 6538-keV α line with a half-life of 139(3) ms was reported from the state in 174 Au with an α-decay branching ratio of 90(6)%.…”

“…5(b) was also calibrated using the α-energy region of respective α decays of 180 Tl. Based on this calibration, the energies of the light and heavy mass peaks in this spectrum are E L = 69.4 (12) and E H = 53.5(12) MeV, which gives a firstorder total kinetic energy of TKE( 180 Hg) = 122.9(17) MeV, which must be corrected for the pulse height defect. This can be done by comparing this value with TKE( 180 Hg) = 133.2 (14) MeV deduced in Ref.…”

Discovery of scandium, titanium, mercury, and einsteinium isotopes

“…Bernas et al observed 56 Sc, 57 Sc, and 58 Sc for the first time in 1997 as reported in their paper ''Discovery and cross-section measurement of 58 new fission products in projectile-fission of 750A Á MeV 238 U'' [34]. Uranium ions were accelerated to 750A Á MeV by the Gesellschaft für Schwerionenforschung (GSI) UNILAC/SIS accelerator facility and bombarded a beryllium target.…”