Multipolarity of some transitions in the96Zr(p,n γ e)96Nb reaction

The conversion electron andγ-ray spectra of the⁹⁶Zr(p, n γ)⁹⁶Nb reaction were measured with Ge(Li) and superconducting magnet transporter Si(Li) spectrometers respectively, at 4MeV bombarding proton energy. The multipolarities of some transitions were determined and conclusions were drawn on the spins and parities of the excited states of⁹⁶Nb.     

Low-spin states of153Gd observed in the decay of153Tb

Level structure of the 89-neutron nucleus¹⁵³Gd has been investigated by studying theEC-decay of isotope-separated¹⁵³Tb sources with several semiconductor detectors. In addition to singles gamma and electron spectra,γ-γ ande ^?-γ coincidences were investigated by using Ge(Li) and Si(Li) spectrometers and a high-capacity two-parameter recording system. In all, 191γ-rays are assigned to the decay of the 2.4d¹⁵³Tb. The proposed level scheme of¹⁵³Gd containing most of the observed transitions shows a very high density of low-spin states (45 states below 1.5MeV). Spin and/or parity assignments based mainly on coincidence data and measured transition multipolarities are proposed for a majority of these states. Nilsson model classifications of some levels are discussed. On the basis of logf t values the spin and parity of the ground state of¹⁵³Tb are suggested to be 3/2⁺ or 5/2⁺.     

The nuclear structure of198Au from the reaction197Au(n, γ)198Au

Precise energies and intensities of about 450γ-rays of the¹⁹⁷Au(n, γ)¹⁹⁸Au reaction have been investigated in the energy range from 30 keV to 1 MeV with a bentcrystal spectrometer. Prompt and delayedγ-γ coincidences have been studied with Ge(Li) detectors. A half-life of 124±4 ns has been measured for the state at 312.036 keV, which is found to decay to the ground state through the cascade 97.195–214.841 keV. A new level scheme based on these results has been constructed which contains 160 transitions. Spin and parity assignments have been made for most of the levels.     

Excited states of100Tc from100Mo(p,nγ)100Tc reaction and the parabolic rule

γ-spectra and excitation functions of the¹⁰⁰Mo(p, nγ)¹⁰⁰Tc reaction were measured in the 1.2–3.6 MeV proton energy range by using thick, enriched targets, Ge(Li) and low energy photon (hyperpure Ge) spectrometers. These detectors were used inγγ-coincidence experiments, too. Conversion electron spectrum measurements were performed by means of a superconducting magnet transporter Si(Li) spectrometer (SMS) atE _p =4 MeV and multipolarities of some transitions have been determined. Based on the experimental results a level scheme of¹⁰⁰Tc has been constructed. Level energies of¹⁰⁰Tc were calculated on the basis of the parabolic rule, derived from the cluster-vibration model.     

Low energy nuclear states in124Te

The energy level scheme of¹²⁴Te has been established on the basis of singlesγ-spectra, andγ-γ coincidence measurements carried out using a dual parameter data collection system. Ge(Li) detectors were used to study the gamma spectra produced in theβ ^? decay of¹²⁴Sb. Eleven new transitions and two new energy levels are proposed. Relative intensities, branching ratios,α(K) and logft values were calculated and multipolarities, spins and parities deduced. Comparisons are made with predictions of the Interacting Boson Model: in a first order perturbation approximation to theSU (5) limit, using the complete IBA-1 Hamiltonian, and in theO(6) limit.     

The decay of63Zn

Energies and relative intensities ofγ-ray transitions in the decay of⁶³Zn have been measured with a Ge(Li) spectrometer in an anti-Compton anti-annihilation set up. Gamma-gamma coincidences and the “energy level spectrum” have been measured. Some aspects of the resulting decay scheme are compared with existing theoretical predictions.     

Studies of the low-lying levels in192Pt and192Os

The energy level schemes of¹⁹²Os and¹⁹²Pt have been established on the basis ofγ- γ coincidence studies using a dual parameter data collection system. Ge(Li) detectors were employed to study the gamma spectra produced in the E.C. andβ ^? decays of¹⁹²Ir to¹⁹²Os and¹⁹²Pt, respectively. Thirteen new transitions and three new levels at 1,146.95, 1,237.35 and 1,913.76 keV are suggested. Relative intensities from singles measurements, branching ratios,α(K) and log ft values were calculated and multipolarities, spins and parities deduced. Comparisons are made with predictions of the Interacting Boson Model calculated on the basis of an O(6) to SU(3) transition.     

Gamma-radiation of193Au

The gamma-radiation of¹⁹³Au has been studied by means of a Ge(Li) semiconductor detector. In addition to the transitions observed by Svahn et. al. (Z. Physik210 (1968), 466), 21 new transitions have been found. With the use of the relative conversion line intensities from the above reference and the -ray intensities of this work, the number of internal conversion coefficients _K has been determined. The multipolarities of the transitions have been deduced from a comparison of the experimental and theoretical _K -values. Some additions to the¹⁹³Au decay scheme were made on the basis of new experimental results.     

Contributions to the decays of109Pd and199Pt

The gamma decays of the 13.5 h¹⁰⁹Pd to levels in¹⁰⁹Ag and those of 30 min¹⁹⁹Pt to levels in¹⁹⁹Au, have been studied with the use of both Ge(Li) gamma-ray and a high resolution iron free double focusing beta-ray spectrometers. TheK-conversion coefficients and multipolarities of gamma-rays were determined. Spin and parity assignments for most of the levels were given on the basis of the conversion coefficients. The level structures of¹⁰⁹Ag and¹⁹⁹Au are discussed in terms of existing nuclear models.     

Der Zerfall des122Xe (T 1/2=20,l h) und des122J (T 1/2=3,6min)

Theγ spectra emitted in the decay of¹²²Xe and¹²²I have been investigated using Ge(Li) detectors and a Ge(Li)-NaI coincidence apparatus. 14γ transitions with energies between 61.8 and 416.9 keV have been identified in the decay of¹²²Xe, 44 transitions between 564.0 and 3,291.0 keV in the decay of¹²²I. Level schemes having 7 excited levels for¹²²I and 21 excited levels for¹²²Te are proposed.     

Radioactive decay of 1.7-h149Nd to levels of transitional149Pm

Sources of¹⁴⁹Nd were produced by thermal-neutron irradiation of enriched¹⁴⁸Nd. High resolution Ge(Li) spectrometers were used to collect gamma-ray singles and coincidence spectra in the study of the decay of 1.7-h¹⁴⁹Nd. A total of 214 gamma rays have been assigned to the decay of¹⁴⁹Nd, and 201 of these transitions have been placed in a level scheme of¹⁴⁹Pm involving 42 excited states. Absolute values for the beta-group intensities were determined for transitions to the¹⁴⁹Pm levels, and spin and parity assignments were made for many of the observed states. The experimentally determined level structure of¹⁴⁹Pm was compared with corresponding levels in other odd-mass Pm and Eu nuclides. Interpretations were made in terms of the core-coupling model. Radioactive decay¹⁴⁸Nd(n, γ)¹⁴⁹Nd; measuredE _γ,I _γ,γ-γ coinc.¹⁴⁹Pm deduced levels,J,π. Compton-suppression. Ge(Li) detector. Enriched targets.     

Gamma-gamma directional correlations and coincidence studies in154Gd

The intensities, placements andE2/M1 mixing ratios of transitions in the decay of¹⁵⁴Eu have been carefully studied to provide accurate data for microscopic calculations. Coincidence relationships in the decay of¹⁵⁴Eu have been studied extensively with a multiparameterγ-γ coincidence system with two large volume Ge(Li) detectors. Spectra in coincidence with twenty energy gates were analyzed. Twenty-nine new coincidence relationships were established and confirmed most, but not all, of several levels previously assigned by energy fits only. From an analysis of coincidence spectra and singles spectra with a 18% efficiency Ge(Li) detector new information on the gamma-ray intensities were obtained. Precise values of theE2/M1 mixing ratios of transitions from the gamma- and beta-vibrational bands to the g.s. band have been determined fromγ-γ directional correlation measurements with a NaI(Tl)-Ge(Li) detector coincidence system. Mixing ratios were obtained for a number of other transitions including those fromK ^π =0^? and 2⁺ bands from direct and skipped cascade correlations.     

A γγ coincidence study of transitions in239Np and239Pu from decay of243Am

Gamma-gamma coincidences and singles measurements with Ge detectors have been made on transitions in²³⁹Np and²³⁹Pu. Eighteen transitions in²³⁹Pu and three in²³⁹Np have been verified by coincidence data. High resolution singles measurements were made and new values for the energy and intensities ofγ-rays below 350 keV were obtained.     

Ground state properties and β-decay half-lives near 132Sn in a self-consistent theory

The level scheme of⁹⁵Tc has been investigated with Ge(Li)-detectors by observing the γ-rays after the decay of 1.65 h⁹⁵Ru. The energies and intensities of theγtransitions were extracted fromγ-singles andγγ-coincidence spectra. In the decay of⁹⁵Ru 88γ-transitions were observed; a scheme of⁹⁵Tc with 25 levels is proposed into which 86 transitions could be accomodated. Spin and parity assignments were made from log (ft) values andγ-ray branching ratios. The level structure of⁹⁵Tc is compared with that of the other odd Tc isotopes.     

The decay of131Ba

The decay of¹³¹Ba has been studied by Ge(Li) detector supplemented by Ge(Li)-Ge(Li) fast-slow coincidence and NaI(Tl)-NaI(Tl) sum-coincidence spectrometer. The existence of 31 gamma rays and the levels at 78.8, 123.5, 133.4, 215.7, 373.0, 585.0, 620.0, 696.3 and 1084.4 keV have been confirmed. No evidences are found for the level at 1170 keV and 215.7?78.8 and 696.3?373.0 transitions. Some transitions are found to be connected with the impurities which were attributed to¹³¹Ba decay in earlier studies. The relative intensities and conversion coefficients have been determined and multipolarities of some of the transitions infered from the comparison of the conversion coefficients with the theoretical values.     

Studies in the decay of103Ru

The decay of¹⁰³Ru to¹⁰³Rh has been studied using a double-focussing spectrometer for the electron and negaton spectra and a Ge(Li) detector for gamma-ray measurements. TheL-conversion groups of the 40, 53, and 497 keV transitions were resolved at high resolution and unambigous multipolarity assignments were obtained for these transitions. The level scheme proposed resembles in principle that suggested by previous investigators. One essential difference is the doublet character of the state around 0.65 MeV. Tentative spin-parity values have been assigned to all levels from the deduced multipolarities and logft values.     

Excited states in195Pt from the decay of 2.3h195Irg, 3.7h195Ir m and 183d195Au

The decay of two previously reported isomers in¹⁹⁵Ir has been investigated with Ge(Li) and Si(Li) detectors by observing β and γ rays as well as conversion electrons in single and coincidence measurements. To about 30 of the 85 observed transitions a multipolarity was assigned. The energies of the gamma rays from¹⁹⁵Au were also determined accurately. The decay scheme of¹⁹⁵Ir shows 13 new levels in¹⁹⁵Pt between 389 and 931 keV. Probable spin and parity assignments could be made to most levels. The results are compared with those of a recent Coulomb excitation study, reaction work and theoretical calculations.     

The β decay of tellurium 135 and 137

Tellerium 135 and 137 nuclei were produced in thermal neutron fission of²³⁵U separated by on-line isotope separator and deposited on a movable tape. Gamma ray singles,γ-γ, β-γ coincidences and time sequencedγ spectra were collected using Ge(Li) detectors and scintillator (NE 102 A) telescope. The half-lives and mass excesses of¹³⁵Te and¹³⁷Te were measured and level schemes of¹³⁵I and¹³⁵I have been established. The level scheme of¹³⁵I has been compared to different shell model calculations.     

On the decay of73Ga to levels in73Ge

Theγ-radiation following the β^? decay of⁷³Ga has been studied. Singlesγ andγγ coincidence spectra were recorded with Ge(Li)-detectors. 17γ-rays were assigned to transitions in⁷³Ge, where 11 excited levels are proposed. From logft values based onγ-transition intensities, spin and parity assignments for the levels were deduced. The half-life of⁷³Ga was measured to (4.86±0.03) h. From allowedβ-transitions the ground state of⁷³Ga was assigned 3/2^?.     

Levels in152Gd and152Sm populated by the decay of152Eu

The energy level schemes of¹⁵²Gd and¹⁵²Sm have been established on the basis of singlesγ-spectra, andγ- γ coincidence measurements. Ge(Li) detectors were used to study the gamma spectra produced in the EC/β⁺ and β^? decays of¹⁵²Eu to¹⁵²Sm and¹⁵²Gd, respectively. Thirteen new transitions are reported and data from eleven coincidence gates enabled five new levels to be suggested. Relative intensities and logf t values were calculated and spin/parities deduced. Comparisons are made with new predictions of the Interacting Boson Model.