H. Schmeing

Decays and masses of 162,163Ta and some neighboring nuclides.

{alpha} groups and {gamma}-ray transitions have been observed from nuclides produced in the bombardment of {sup 40}Ca with {sup 127}I. Two weak {alpha} groups were assigned to {sup 162,163}Ta based on their measured half-lives and excitation functions. With an unambiguous assignment of these two {alpha} groups the absolute masses of nuclides in two long {alpha} chains, for which {sup 162,163}Ta form links, can now be deduced with confidence. Absolute masses are thus obtained for some nuclides very far from stability, including ones that are not bound against ground-state proton emission. The simultaneous observation of {alpha} groups and {gamma} rays from other nuclides produced in this bombardment also permitted the determination of the upper limits of six new {alpha} branching ratios.

Decay studies of the new isotopesHf162,163

The new isotopes 72/sup 163/Hf (T/sub 1/2/ = 40.0(6) s) and /sub 72//sup 162/Hf (T/sub 1/2/ = 37.6(8) s) were produced in 60/sup 142/Nd /sub 12//sup 24/Mg, xn) reactions and transported to a measuring station by use of the He-jet technique. Decay properties were observed with ..cap alpha..,..gamma.., and ..gamma..-..gamma.. spectroscopy. The Z assignment of the new isotopes was based on a cross bombardment, /sub 12//sup 24/Mg + 59/sup 141/Pr, and on results of ..gamma..-x-ray conicidence measurements. The mass assignment was deduced from measured excitation functions. Beta-delayed ..gamma.. rays were identified, 11 for /sup 163/Hf and 3 for /sup 162/Hf, and level schemes for 71/sup 163/Lu and /sub 71//sup 162/Lu are proposed based on the results of intensity and ..gamma..-..gamma.. coincidence measurements. A small ..cap alpha.. branch (I/sub ..cap alpha../ = 0.0087 (/sub -/37/sup +17/)%) with a decay energy of E/sub ..cap alpha../ = 4308 (10) keV was found in the decay of /sup 162/Hf. The reduced ..cap alpha.. width W/sub ..cap alpha../ = 2.6( /sub -1.2/) for /sup 162/Hf is in accordance with those for neighboring nuclei. With the new /sup 162/Hf ..cap alpha..-decay energy, mass values were derived for 72/sup 162/Hf, /sub 74//sup 166/W, 74/sup 166/W, 76/sup 170/Os,morexa0» /sub 78//sup 174/Pt, and 80/sup 178/Hg. The new masses as well as values deduced for two-proton binding energies are compared with predictions of current mass formulas.«xa0less

Decays and Masses of Ta-162,ta-163 and some Neighboring Nuclides

{alpha} groups and {gamma}-ray transitions have been observed from nuclides produced in the bombardment of {sup 40}Ca with {sup 127}I. Two weak {alpha} groups were assigned to {sup 162,163}Ta based on their measured half-lives and excitation functions. With an unambiguous assignment of these two {alpha} groups the absolute masses of nuclides in two long {alpha} chains, for which {sup 162,163}Ta form links, can now be deduced with confidence. Absolute masses are thus obtained for some nuclides very far from stability, including ones that are not bound against ground-state proton emission. The simultaneous observation of {alpha} groups and {gamma} rays from other nuclides produced in this bombardment also permitted the determination of the upper limits of six new {alpha} branching ratios.

Decays and masses of sup 162,163 Ta and some neighboring nuclides

{alpha} groups and {gamma}-ray transitions have been observed from nuclides produced in the bombardment of {sup 40}Ca with {sup 127}I. Two weak {alpha} groups were assigned to {sup 162,163}Ta based on their measured half-lives and excitation functions. With an unambiguous assignment of these two {alpha} groups the absolute masses of nuclides in two long {alpha} chains, for which {sup 162,163}Ta form links, can now be deduced with confidence. Absolute masses are thus obtained for some nuclides very far from stability, including ones that are not bound against ground-state proton emission. The simultaneous observation of {alpha} groups and {gamma} rays from other nuclides produced in this bombardment also permitted the determination of the upper limits of six new {alpha} branching ratios.

Decay of sup 120 Ba

The decay of {sup 120}Ba has been studied with an on-line isotope separator. Its half-life was determined to be {ital t}{sub 1/2}=24{plus minus}2 s. A decay scheme is proposed, based on {gamma}-{gamma}, {gamma}-{ital X}, and {gamma}-{beta}{sup +} coincidence measurements, which takes account of all 16 observed {gamma} rays. The total decay energy was measured to be {ital Q}{sub EC}=50{plus minus}0.3 MeV.

Decay Studies of the New Isotopes Hf-162,hf-163

The new isotopes 72/sup 163/Hf (T/sub 1/2/ = 40.0(6) s) and /sub 72//sup 162/Hf (T/sub 1/2/ = 37.6(8) s) were produced in 60/sup 142/Nd /sub 12//sup 24/Mg, xn) reactions and transported to a measuring station by use of the He-jet technique. Decay properties were observed with ..cap alpha..,..gamma.., and ..gamma..-..gamma.. spectroscopy. The Z assignment of the new isotopes was based on a cross bombardment, /sub 12//sup 24/Mg + 59/sup 141/Pr, and on results of ..gamma..-x-ray conicidence measurements. The mass assignment was deduced from measured excitation functions. Beta-delayed ..gamma.. rays were identified, 11 for /sup 163/Hf and 3 for /sup 162/Hf, and level schemes for 71/sup 163/Lu and /sub 71//sup 162/Lu are proposed based on the results of intensity and ..gamma..-..gamma.. coincidence measurements. A small ..cap alpha.. branch (I/sub ..cap alpha../ = 0.0087 (/sub -/37/sup +17/)%) with a decay energy of E/sub ..cap alpha../ = 4308 (10) keV was found in the decay of /sup 162/Hf. The reduced ..cap alpha.. width W/sub ..cap alpha../ = 2.6( /sub -1.2/) for /sup 162/Hf is in accordance with those for neighboring nuclei. With the new /sup 162/Hf ..cap alpha..-decay energy, mass values were derived for 72/sup 162/Hf, /sub 74//sup 166/W, 74/sup 166/W, 76/sup 170/Os,morexa0» /sub 78//sup 174/Pt, and 80/sup 178/Hg. The new masses as well as values deduced for two-proton binding energies are compared with predictions of current mass formulas.«xa0less

Decay studies of the new isotopes /sup 162,163/Hf

The new isotopes 72/sup 163/Hf (T/sub 1/2/ = 40.0(6) s) and /sub 72//sup 162/Hf (T/sub 1/2/ = 37.6(8) s) were produced in 60/sup 142/Nd /sub 12//sup 24/Mg, xn) reactions and transported to a measuring station by use of the He-jet technique. Decay properties were observed with ..cap alpha..,..gamma.., and ..gamma..-..gamma.. spectroscopy. The Z assignment of the new isotopes was based on a cross bombardment, /sub 12//sup 24/Mg + 59/sup 141/Pr, and on results of ..gamma..-x-ray conicidence measurements. The mass assignment was deduced from measured excitation functions. Beta-delayed ..gamma.. rays were identified, 11 for /sup 163/Hf and 3 for /sup 162/Hf, and level schemes for 71/sup 163/Lu and /sub 71//sup 162/Lu are proposed based on the results of intensity and ..gamma..-..gamma.. coincidence measurements. A small ..cap alpha.. branch (I/sub ..cap alpha../ = 0.0087 (/sub -/37/sup +17/)%) with a decay energy of E/sub ..cap alpha../ = 4308 (10) keV was found in the decay of /sup 162/Hf. The reduced ..cap alpha.. width W/sub ..cap alpha../ = 2.6( /sub -1.2/) for /sup 162/Hf is in accordance with those for neighboring nuclei. With the new /sup 162/Hf ..cap alpha..-decay energy, mass values were derived for 72/sup 162/Hf, /sub 74//sup 166/W, 74/sup 166/W, 76/sup 170/Os,morexa0» /sub 78//sup 174/Pt, and 80/sup 178/Hg. The new masses as well as values deduced for two-proton binding energies are compared with predictions of current mass formulas.«xa0less