Decay studies of the new isotopes ${}^{162, 163}{Hf}$

The new isotopes

{}_{72}^{163}{Hf}

[

T_{\frac{1}{2}} = 40.0 (6)

s] and

{}_{72}^{162}{Hf}

[

T_{\frac{1}{2}} = 37.6 (8)

s] were produced in

{}_{60}^{142}{Nd}

(

{}_{12}^{24}{Mg}

xn

) reactions and transported to a measuring station by use of the He-jet technique. Decay properties were observed with

α

γ

, and

γ - γ

spectroscopy. The

Z

assignment of the new isotopes was based on a cross bombardment,

{}_{12}^{24}{Mg}

{}_{59}^{141}\Pr

, and on results of

γ

-x-ray coincidence measurements. The mass assignment was deduced from measured excitation functions. Beta-delayed

γ

rays were identified, 11 for

{}^{163}{Hf}

and 3 for

{}^{162}{Hf}

, and level schemes for

{}_{71}^{163}{Lu}

and

{}_{71}^{162}{Lu}

are proposed based on the results of intensity and

γ - γ

coincidence measurements. A small

α

branch [

I_{α} = {0.0087}_{(- 37}^{+ 17)}

%] with a decay energy of

E_{α} = 4308

(10) keV was found in the decay of

{}^{162}{Hf}

. The reduced

α

width

W_{α} = {2.6}_{(- 1.2}^{+ 0.6)}

for

{}^{162}{Hf}

is in accordance with those for neighboring nuclei. With the new

{}^{162}{Hf}

α

-decay energy, mass values were derived for

{}_{72}^{162}{Hf}

{}_{74}^{166}W

{}_{76}^{170}{Os}

{}_{78}^{174}{Pt}

, and

{}_{80}^{178}{Hg}

. The new masses as well as values deduced for two-proton binding energies are compared with predictions of current mass formulas.

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Decay studies of the new isotopesHf162,163