The Decay of130La to levels in130Ba

Theγ-radiation associated with the β⁺ decay of¹³⁰La to levels in¹³⁰Ba is studied. The level scheme is established on the basis of theγ-γ coincidence measurements emploing two Ge(Li) detectors. The available experimental data are compared to collective model calculations withγ-soft P.E.S. andγ-dependent inertial functions. To reproduce levels energyB _ββ value twice as large as other mass parameters is needed.Radioactivity: ¹³⁰La [from¹³⁰Ba(p, n),E _p=10MeV]; measuredE _γ,I _γ,γγ-coin.¹³⁰Ba deduced levels,J, π, logft. Enriched target, Ge(Li) detectors.     

High-spin states in106Cd

Levels of¹⁰⁶Cd, populated by¹⁰⁴Pd(α, 2nγ)¹⁰⁶Cd have been studied measuring direct and delayedγ-ray spectra,γ-γ coincidences andγ-ray angular distributions. A decay level scheme is proposed including states up to 4659.8 keV. IntenseE2 transition cascades have been observed. The half-life of an isomeric level located at 4659.8 keV has been measured:T _1/2= 62±6ns. Nuclear Reactions ¹⁰⁴Pd(α, 2nγ),E _α=31MeV; measuredE _γ,I _γ,γ-γ coinc, σ(θ)T _1/2.¹⁰⁶Cd deduced levels,J, π, Enriched targets. Ge(Li) detectors.     

Negative-parity bands in the 88-neutron nuclei153Tb and155Ho

Bands of negative-parity levels have been observed in in-beam studies of¹⁵³Tb and¹⁵⁵Ho. The data are qualitatively accounted for in the rotation-alignment model as decoupled bands based on the h_11/2 proton orbital. Nuclear Reactions:¹⁵³Eu(α, 4nγ)¹⁵³Tb,E=45–55 MeV;¹⁵⁰Sm(¹⁰B, 5nγ)¹⁵⁵Ho,E=60–70 MeV; measuredE _γ,I _γ (0), γ ? γ coinc.,E _e, I _e ^K ,¹⁵³Tb and¹⁵⁵Ho deduced levels,J, π. Ge(Li) and Si(Li) detectors. Enriched targets.     

Konversionskoeffizienten und Fluoreszenzausbeuten beim Zerfall des Hg199m

Hg^199m was produced by bombarding natural HgO with fast neutrons. The conversion electrons of the cascade decay were investigated with Si(Li)-counters. By application of the summing technique the conversion coefficients andL-shell fluorescence yields of Hg were determined. The gamma rays were studied with a Ge(Li)-counter. The following results were obtained: half-lifeT _1/2=(42.6± 0.2) min; energies of the transitionsE _γ1=(374.1± 0.1) keV,E _γ1=(158.3± 0.1)keV; intensity ratio of the gamma raysI _γ(158 keV):I _γ(374keV)=(424± 42):100; conversion coefficients α_K158=0.30± 0.03, α_total158=0.94± 0.09, α_K158/α_LM...158=0.47± 0.02, α_L158/α_M...158=3.10± 0.16;α_K374=3.51± 0.28,α_total1374=6.19±0.47,α_K374/α_LM...374=1.32±0.04, α_L374/α_M...374=2.14±0.11;L-shell fluorescence yields \(\bar \omega _L \) =0.40± 0.04, ω_KL=0.41±0.04.     

Transition probabilities and the structure of some negative-parity states in126,130Xe and132Ba

The lifetimes of several negative-parity states in^126,130Xe and¹³²Ba have been determined by means of the generalized centroid-shift method. The reactions^124,128Te(α,2n) and¹²²Sn(¹³C, 3n) have been used. Following results were obtained:T _1/2(2758 keV)=1.3±0.2 ns in¹²⁶Xe,T _1/2(2060 keV)=0.20±0.10 ns,T _1/2(2104 keV)=0.50±0.10 ns,T _1/2(2376 keV)=0.30±0.10 ns andT _1/2(2973 keV)=4.6±0.4 ns in¹³⁰Xe as well asT _1/2(2120 keV)=0.40 _?0.10 ^+0.20 ns in¹³²Ba. A systematics of the B(E2; 7 _? ¹ ?5 ₁ ^? ) values in theN=76 nuclei is presented. Electric dipole and quadrupole transition rates are discussed in terms of octupole and quadrupole collectivity. The structure of the 5 ₁ ^? and 7 ₁ ^? states is considered. Nuclear reactions:^124,128Te(α, 2 _n ),E=26 MeV,¹²²Sn (¹³C, 3n),E=53 MeV; measuredE _γ I _γ , γ-r.f. DeducedT _1/2, B(σL) in^126,130Xe and¹³²Ba. Ge detectors. Generalized centroid-shift analysis.     

In beam gamma spectroscopy of62Zn

The decay scheme of⁶²Zn has been investigated by studying the yield functions, angular distributions and coincidence relation-ships of theγ-rays emitted in the⁶³Cu(p, 2nγ) and⁶⁰Ni(α, 2nγ) reactions. Spins up to7? were assigned to the observed states. Nuclear Reactions ⁶⁰Ni(α, 2nγ)⁶²Zn,E _α=28–35 MeV and⁶³Cu(p, 2nγ)⁶²Zn,E _p = 22–31 MeV; measuredE _γ,I _γ(θ),I _γ(E _p , andI _γ,E _α-γ coincidences,⁶²Zn deduced decay scheme. Enriched target, Ge(Li) detectors.     

High spin states in73Se observed by the reaction70Ge(α,nγ)

⁷³Se has been investigated by the reaction⁷⁰Ge(α, nγ). Gamma excitation functions (E _α=10–16 MeV), gamma angular distributions (E _α=18 MeV) and gamma-gamma coincidences (E _α=15 MeV)) have been taken. A level scheme has been established, spins and partities have been assigned. States of a rotational band on the 151.2 keV (5/2^?) state and an anomalous band have been identified. Nuclear Reaction⁷⁰Ge(α,nγ)E _α=15 and 18 MeV; measuredE _γ,I _γ,γ-γ-coin.,γ-angular distribution,γ-excitation function.⁷³Se deduced levels,J, π. Enriched target, Ge(Li).     

Suche nach dem Isomer74mAs

An activity with the decay propertiesT _1/2=(8.0±0.3)sec andE _γ=(283±5)keV has been produced bySchardt andGoodman by proton irradiation of thin layers of evaporated⁷³Ge and⁷⁴Ge on thick gold backings. This activity was interpreted as the new isomer^74mAs. In the present experiment a search for^74mAs was carried out using the reactions⁷⁵As(n, 2n),⁷¹Ga(α, n) and⁷⁴Ge(d, 2n).^74mAs could not be detected. Upper limits for the reaction cross sections were determined. It is discussed that the reported properties of^74mAs resemble the known properties of^197mAu.     

Parities of strong dipole ground state transitions in88Sr

By on-line mass separation and subsequent gamma and electron decay-spectroscopy at very low energy, two new isomers,^124mCs (T_1/2=6.3 ±0.3 seconds) and^127mBa (T_1/2=1.9±0.2 seconds) have been identified.     

79Se investigated by the reaction76Ge(α, nγ)

⁷⁹Se has been investigated by the reaction⁷⁶Ge(α, nγ). Gamma excitation functions (E _{α=10?15 MeV)}, gamma angular distributions and gamma-gamma coincidences (both at (E _{α=12 MeV)}, have been taken. A level scheme has been established, spins and partities have been assigned. The results are compared with rotational bands in neighbouring odd Se isotopes. Nuclear reaction⁷⁶Ge(α, nγ)E _α =12 MeV; measuredE _γ,I _γ,γ-γ coincidences,γ-angular distribution,γ-excitation function.⁷⁹Se deduced levels,J, π. Enriched target, Ge(Li).     

Untersuchung der Anregungen von186Re nach der (n, γ)-Reaktion

Prompt and delayedγ-γ-coincidences were measured after slow neutron capture in¹⁸⁵Re by use of Ge(Li)-detectors. New isomers were found at 99.4 keV (T_1/2=27±7ns) and at ≈330keV (T_1/2=17.4±0.7 ns). The evaluation of coincidence data established 10 rotational bands with band heads below 700 keV. The level scheme is discussed in detail: Nilsson assignments are proposed for the band configurations, and calculations of Coriolis mixing andγ-transition probabilities are presented which reproduce the experimental level energies and transition intensities very satisfactorily.     

Decay of90m,g Rb

The decay of mass separated⁹⁰Rb has been studied usingβ,γ and conversion electron spectrometers in single and coincidence modes. The half-lives of the ground state and the isomeric level have been confirmed to be 162± 3 and 258±4 s, respectively. Theγ-rays from the decays of ground state and metastable state have been identified by measuring the decay of individual photopeaks using Ge(Li) detectors. The multipolarity of the 106.6 keV isomeric transition has been determined to beM3. Separate decay schemes of the ground and metastable states are presented. The levels of⁹⁰Sr are discussed in terms of the available experimental and theoretical information. Radioactivity.^90m,gRb [from²³⁸U(p, f)]; measuredT _1/2,E _γ,I _γ,γ—γ coin,I _ce,cc,E _β deduced logft,⁹⁰Sr levels, mass separated⁹⁰Rb.     

Der Zerfall des125m Xe,des127m Xe und des127g Xe

The decay of^125m Xe produced by the reaction¹²²Te(α, n)^125m Xe using a target enriched in¹²²Te (95.4%) and the decay of^127m Xe produced by the reaction¹²⁷J(d, 2n)^127m Xe have been investigated: ^125m Xe decays with a half-life ofT _1/2=(56±3) sec by ayy- cascade withE _γ1=(140.4 ±0.5) keV andE _γ2=(110.5 ±0.5) keV. The experimental conversion coefficients yield multipolarities ofE3 for the 140.4 keV isomeric transition and predominantlyM1 for the 110.5 keV-transition. ^127m Xe decays with a half-life ofT _1/2=(71±2) sec. The decay also proceeds by aγγ-cascade with an isomeric E3 transition ofE _γ1=(172.5±0.3) keV and a predominantlyM1 transition ofE _γ2=(124.6±0.3) keV. In the decay of^127g Xe an additional branching of the electron capture to a level at (618.1±0.3) keV was observed. The relative probability forK-captureP _K618/P_K375=0.40 ±0.07 yields a total transition energyQ _EC=(664 ±4)keV. A spin of 1/2⁺ was assigned to the ground state.     

High spin states in75Se populated by the72Ge(α,n) and73Ge(α, 2n) reaction

The⁷²Ge(α, n)⁷⁵Se and⁷³Ge(α, 2n)⁷⁵Se reactions have been studied at bombarding energies of 15 MeV and 22.5 MeV respectively using Ge(Li)-detectors.γ-singles spectra,γ-γ-coincidences,γ-angular distributions and excitation functions have been taken. A level scheme has been constructed, which contains a stretched spin and a normal rotational band. Nuclear reactions⁷²Ge(α, n)⁷⁵Se,⁷³Ge(α, 2n)⁷⁵Se; measuredE _γ ,I _γ ,γ-γ-coincidences,γ-angular distribution,γ-excitation function.⁷⁵Se deduced levels,J, π, γ-multipolarity. Enriched target, Ge(Li).     

High spin states in77Se populated by the74Ge(α,n γ) reaction

⁷⁷Se has been investigated by the reaction⁷⁴Ge(α,nγ) at 14 MeV. Gamma singles spectra, gamma angular distributions and gamma-gamma coincidences have been taken. A level scheme has been established, spins and parities have been assigned. States of a rotational band on the 1/2^? ground state, a rotational band on the 5/2^? 249.7 keV state and an anormal band have been identified. Nuclear Reaction ⁷⁴Ge(α,n γ)E _α=14 MeV; measuredE _γ ,I _γ ,γ-γ-Coin.,γ-ang. distr.⁷⁷Se deduced levels,J, π. Enriched target, Ge (Li).     

The level structure of69Ge

Theγ-ray decay of the states in⁶⁹Ge has been studied using the reaction⁶⁶Zn(α, nγ)⁶⁹Ge atE _α =13 and 19 MeV. The level scheme and spin assignments were established by means of coincidence measurements, angular distributions and excitation functions. 27 new levels could be found or confirmed. It is suggested that⁶⁹Ge is a further example for the weak coupling phenomenon in the medium mass nuclei. Nuclear Reactions: ⁶⁶Zn(α, nγ)⁶⁹Ge,E _α =13–22 MeV, measuredE _γ ,I _γ ,I _γ (θ),E _γ =f(E _α ),γ-γ coincidences,⁶⁹Ge deduced levels,J, enriched target.     

E2 transition probabilities in77Br

⁷⁷Br has been investigated by the reaction⁶⁴Ni(¹⁶O,p2nγ) at 60 MeV. The following mean lives (in parentheses) have been determined by the recoil distance Doppler shift method (energies in keV): 161.9 (718±50 ps), 575.2 (14.2±2.1 ps), 639.0 (14.1±0.8 ps), 782.0 (4.3±0.9 ps), 790.1 (6.2±0.8 ps), 1,273.2 (4.0±1.0 ps), 1,303.0 (4.0±1 ps), 1,480.8 (0.6 ±0.2 ps). The resultingB(E2) values are compared with rotor plus particle calculations. Nuclear reaction⁶⁴Ni(¹⁶O,p2nγ)E ₀=60 MeV; measuredE _γ, recoil distance Doppler shift; deducedT _1/2. Enriched target, Ge(Li).     

The decay of83gSe and83mSe

The decay of the isomeric pair^83gSe (T1/2=22.6 min,I ^α = 9/2⁺) and^83mSe (T1/2=70 s,I ^α = 1/2^?) has been reinvestigated using straight Ge(Li) (^83gSe and^83mSe) and Ge(Li)-Ge(Li) coincidence spectrometry (^83gSe). Both decays populate entirely different⁸³Br levels, 11 of them being previously unreported. Fromγ-ray unbalances and from the known isomeric cross-section ratio of⁸²Se, β^?-branchings have been obtained, including a 34% branching of^83mSe to the ground state of⁸³Br. Logft-values are deduced, spin and parity values proposed and discussed.     

Low-lying 134Cs excited states from the (n, γ) reaction

Low-energy γ-ray and conversion electron spectra from the ¹³³Cs(n,γ)¹³⁴Cs reaction have been investigated with a bent cyrstal spectrometer, β-speetrometer, Ge(Li) and Si(Li) detectors. Gamma-gamma coincidence measurements were made with the Ge(Li)-Ge(Li) arrangement. Gamma-gamma delayed coincidences have been studied with the use of the Ge(Li)-NaI(Tl) coincidence set-up. The decay of 2.9 h ^134mCs has been investigated with the prism β-spectrometer and Ge(Li) detector. The half-lives of the 176.403 and 257.112 keV levels have been measured to be 49.7 ± 0.8ns and 12.3 ± 1.1 ns respectively. The neutron binding energy B_n have been calculated to be 6891.4 ± 1.3 keV. Spin and parity assignments have been made for almost all the levels. The possible structure of the levels deduced is discussed.     

Nuclear levels in152Eu

The transitional nucleus¹⁵²Eu has been studied using the (n, e), (n, γ), (n _res,γ), (n, γγ), (d, p), (d, t) and (p, d) reactions. The experiments have been performed at nine different laboratories. A model independent level scheme was established including 95 levels below 510 keV and nearly 900 transitions by combination of low energy transitions and reaction data. More than 20 additional levels result from gamma rays and/or charged particle reactions. The level scheme is interpreted in terms of the Nilsson model indicating that¹⁵²Eu is a deformed nucleus. Seven rotational bands and Nilsson configurations are established. An additional 27 rotational bands are tentatively or speculatively assugned. Gallagher-Moszkowski splittings are discussed. The neutron binding energy was determined as 6305.2±0.5 keV. The energy of the 9.3 h 0^? isomer is 45.599 keV. The lifetimes of four levels were measured. Nuclear Reactions¹⁵¹Eu(n,γ),E _n =thermal and resonance; measuredE _γ ,I _γ ,E _c.e.,I _c.e.,γγ Coinc.,γγΔt coinc.;¹⁵¹Eu(d, p),E=12MeV and 14MeV;¹⁵³Eu(d, t),E=12MeV;¹⁵³Eu(p, d),E =18MeV; deduced level scheme of¹⁵²Eu,J, π, T _1/2,cc, Nilsson configurations. Magnetic electron spectrometer, curved crystal spectrometer, Ge(Li) and Si(Li) detectors, magnetic spectrographs. Enriched targets.