A. Perego

Decay properties of the 02+ state and spin-parity assignments in 78Kr.

The lifetime {tau} of the 0{sub 2}{sup +} state in {sup 78}Kr has been measured by means of the Doppler shift attenuation method in gases. From the value of {tau} and the measured value of the {ital K}-internal conversion branching {ital I}{sub {ital K}}(0{sub 2}{sup +}{r_arrow}0{sub 1}{sup +})/{ital I}{sub {ital K}}(0{sub 2}{sup +}{r_arrow}2{sub 1}{sup +}) the value of the electric monopole strength {rho}{sup 2}({ital E}0) of the 0{sub 2}{sup +}{r_arrow}0{sub 1}{sup +} transition has been deduced. Restriction or assignments for the spin parity of several levels in {sup 78}Kr, populated in the decay of {sup 78}Rb, have been deduced by measuring {ital K}-internal conversion coefficients of the relevant transitions.

Transition probabilities in the X(5) candidate

To investigate the possible X(5) character of {sup 122}Ba, suggested by the ground-state band energy pattern, the lifetimes of the lowest yrast states of {sup 122}Ba have been measured, via the recoil distance Doppler-shift method. The relevant levels have been populated by using the {sup 108}Cd({sup 16}O,2n){sup 122}Ba and the {sup 112}Sn({sup 13}C,3n){sup 122}Ba reactions. The B(E2) values deduced in the present work are compared to the predictions of the X(5) model and to calculations performed in the framework of the IBA-1 and IBA-2 models.

^{122}

TheK-conversion coefficients of some 2i+ → 2f+ transitions in102Ru have been measured and their electric monopole components have been deduced. The intensity of theE0 component in the 23+ → 21+ transition supports a possible interpretation, based on gamma decay, of the 23+ level as the lowest mixed-symmetry state. Negative parity has been assigned to the level at 2261 keV.

Ba

The lifetime {tau} of the 0{sub 2}{sup +} state in {sup 78}Kr has been measured by means of the Doppler shift attenuation method in gases. From the value of {tau} and the measured value of the {ital K}-internal conversion branching {ital I}{sub {ital K}}(0{sub 2}{sup +}{r_arrow}0{sub 1}{sup +})/{ital I}{sub {ital K}}(0{sub 2}{sup +}{r_arrow}2{sub 1}{sup +}) the value of the electric monopole strength {rho}{sup 2}({ital E}0) of the 0{sub 2}{sup +}{r_arrow}0{sub 1}{sup +} transition has been deduced. Restriction or assignments for the spin parity of several levels in {sup 78}Kr, populated in the decay of {sup 78}Rb, have been deduced by measuring {ital K}-internal conversion coefficients of the relevant transitions.