The decay of45Ti to45Sc

The low intensity β⁺/E.C. branches in the decay of⁴⁵Ti to excited states of⁴⁵Sc have been reinvestigated in order to resolve discrepancies in reported branching ratios. A new branch to the 974 keV level, having an intensity of 9.9±1.2×10^?5/decay has been found. A previously reported branch to the 1237 keV level was found to be in error. The intensities for decay to the levels at 720, 1408 and 1661 keV levels were determined to be 154±12, 90.2±9.7 and 52.5±5.6, respectively, in units of 10^?5 per decay.     

Levels in 156Gd studied in the (n, γ) reaction

Levels up to 2.3 MeV in ¹⁵⁶Gd have been studied using the (n, γ) reaction. Energies and intensities of low-energy γ-rays and electrons emitted after thermal neutron capture have been measured with a curved-crystal spectrometer, Ge(Li) detectors and a magnetic electron spectrometer. High-energy (primary) γ-rays and electrons have been measured with Ge(Li) detectors and a magnetic spectrometer. The high-energy γ-ray spectrum has also been measured in thermal neutron capture in 2 keV resonance neutron capture. The neutron separation energy in ¹⁵⁶Gd was measured as S_n = 8535.8 ± 0.5 keV.About 600 transitions were observed of which ~50% could be placed in a level scheme containing more than 50 levels up to 2.3 MeV excitation energy. 42 of these levels were grouped into 15 excited bands. In addition to the β-band at 1050 keV we observe 0⁺ bands at 1168, 1715 and 1851 keV. Other positive-parity bands are: 1⁺ bands at 1966, 2027 and 2187 keV; 2⁺ bands at 1154 (γ-band) and 1828 keV; and 4⁺ bands at 1511 and 1861 keV. Negative-parity bands are observed at 1243 keV (1^?), 1366 keV (0^?), 1780 keV (2^?) and 2045 keV (4^?). Reduced E2 and E0 transition probabilities have been derived for many transitions. The ground band, the β- and γ-bands and the 0⁺ band at 1168 keV have been included in a phenomenological four-band mixing calculation, which reproduces well the experimental energies and E2 transition probabilities.The lowest three negative-parity (octupole) bands of which the 0^? and the 1^? bands are very strongly mixed, were included in a Coriolis-coupling analysis, which reproduces well the observed energies. The E1 transition probabilities to the ground band are also well reproduced, while those from the higher-lying 0⁺ bands to the octupole bands are not reproduced. Absolute and relative transition probabilities have been compared with predictions of the IBA model and the pairingplus-quadrupole model. Both models reproduce well the E2 transitions from the γ-band, while strong disagreements are found for the E2 transitions from the β-band. The IBA model predicts part of the decay features of the higher lying 2⁺₂, 4⁺₁ and 2^?₁ bands.     

The β-decay of 47V

The γ-rays emitted following the β-decay of ⁴⁷V have been studied with a 65 cm³ Ge(Li) detector. Direct β-branches were observed to the following levels in ⁴⁷Ti (log ft values in parentheses): ground state (4.9); 1550 keV (6.0); 1794 keV (5.1); 2163 keV (5.3); 2167 keV (6.2); 2526 keV (5.4); 2549 keV (5.7); 2793 keV (5.0). The branches to the last four levels have not been reported previously. In addition, a newγ-decay branch, 2163 → 160 keV, was observed. These results, together with information from reaction studies, permit the assignment of spin and parity $\text{3}\text{2}{}^{\mathrm{?}}$ to the 2163 keV level, and $\text{5}\text{2}{}^{\mathrm{?}}$ to the 2167 keV level. The half-life of the ⁴⁷V decay was measured to be 32.6±0.3 min.     

Level structure in 213Bi

By performing α?γ-coincidence measurements, more precise data on the weak ²¹⁷At α-decay to excited levels of ²¹³Bi have been obtained. A new branch of the α-decay (0.005% per decay) to the 758.9 keV ²¹³Bi level is observed. The structure of the proposed ²¹³Bi levels (0.0 keV 9/2^?, 257.9 keV 7/2^?, 593.1 keV (5/2–9/2)^? and 758.9 keV (5/2–13/2)^?) is discussed in the framework of the shell model.     

Decay of 17-min, 19/2−129mSb

A 17.1min, 19/2^? isomer has been established in¹²⁹Sb at 1851 keV. It is fed by levels populated in the decay of the 6.2min, 11/2^?129Sn isomer. This isomer decays by an M4, 723keV internal transition and by β^? decay to levels in¹²⁹Te. The 723keV transition is 20 times slower than 11/2^?→3/2⁺ M4 transitions in the adjacent odd-N nuclides and is 10 times faster than the M4 transition from the 19/2^? isomer in¹³⁵Cs. A partial level scheme for the decay of the 11/2^?,¹²⁹Sn isomer is given showing levels that populate the 19/2^? isomer along with a partial level scheme for¹²⁹ Te.     

Structure of the Triplet of low-lying states in101Mo

The properties of the triplet of low-lying states in¹⁰¹Mo have been studied through spectroscopy of theγ radiation following thermal neutron capture in¹⁰⁰Mo and β^? decay of¹⁰¹Nb and through a measurement of the proton angular distributions in the¹⁰⁰Mo(d,p) reaction with 14 MeV deuteron energy. The half-lives of the 13.5 keV state and the 57.0 keV 5/2⁺ state have been measured as 226(7) and 133(7)ns, respectively. These values and the quadrupole/dipole mixing ratios of the 13.5 keV and 43.5 keV transitions yield spin and parity 3/2⁺ for the 13.5 keV level. The E2 components in the 13.5 (3/2⁺ →1/2⁺) and 43.5 keV (5/2⁺→3/2⁺) transitions are ≦ 8·10^?4 and 54(9)%, respectively. The possibility of an additional state near to the 57.0 keV level is discussed. IBFM/PTQM calculations, taking into consideration the transitional character of the¹⁰⁰Mo boson core, account for the electromagnetic-transition and transfer-reaction pattern of the triplet of states.     

Levels of 190Os populated in the decays of 3.3 h 190mRe and 12 d 190Ir and in the 189Os(d,p)190Os reaction

The level structure of ¹⁹⁰Os has been investigated by the techniques of radioactive decay and neutron transfer reaction spectroscopy. The existence of 3.3 h ^190mRe has been confirmed; it decays ≈ 49% by isomeric transitions and ≈ 51% by β^? decay to levels in ¹⁹⁰Os with spins $\text{\$}\text{?}\text{= 5}$. In a re-investigation of the 12 d ¹⁹⁰Ir decay, a virtually complete decay scheme has been established and discrepancies between the I^π values assigned to several ¹⁹⁰Os levels by earlier workers have been resolved. The reaction ¹⁸⁹Os(d, p)¹⁹⁰Os has been studied and information about the locations of two-quasiparticle states involving the $\text{3}\text{2}\text{[512]ν}$ orbital and about the microscopic compositions of collective excitations has been derived. Various aspects of the ¹⁹⁰Os level structure are discussed in the light of the combined radioactivity and transfer reaction results.     

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.     

The decay of 1.4 min173Er

A 1.4 ± 0.1 min activity which is assigned to β^?-decay of ₆₈ ¹⁷³ Er has been produced with 14–15 MeV neutrons through the reaction¹⁷⁶Yb(n, α)¹⁷³Er. Its decay has been studied with Ge(Li) detectors and several (γ)(γ) as well as (γ)(β) coincidence arrangements. Eight gamma rays with energies 94.2, 116.14, 118.6, 122.40, 192.8, 199.2, 800.8 and 895.2 keV were assigned to the decay of¹⁷³Er. The proposed level scheme of the daughter nuclide ₆₉ ¹⁷³ Tm contains levels at 0, 2.5, 118.6, 124.9, 317.7, 411.9 and 1212.8 keV. The 317.7 keV level is an isomeric state with a measured half-life of 10±3 μs. This 10 μs isomer and the 411.9 keV level are thought to be the band head and 9/2^? rotational member of 7/2^? [523] Nilsson state, respectively. The levels at 0, 2.5, 118.6 and 124.9 keV are interpreted as 1/2⁺, 3/2⁺, 5/2⁺ and 7/2⁺ members of the 1/2⁺ [411] band and the level at 1212.8 keV as the 9/2^? [514] Nilsson state. Some systematic considerations and theoretical transition probability calculations are also included.     

Study of from the Decay of

The decay of ¹⁴⁰ ₅₇La (40.3 h) to levels in ¹⁴⁰ ₅₈Ce has been studied in the present work. The energies and relative intensities of 37 gamma-rays following the β^? decay of ¹⁴⁰ ₅₇La have been measured with high precision using Ge(Li) and HP.Ge spectrometers. log (ft) values of beta decay were determined from our gamma ray intensities using the beta branchings and a decay scheme is deduced. The sum-peak technique has been used to determine k-conversion coefficient of the transition 1596.41 keV and was found to be 6.98x10^?4 in an excellent agreement with the theoretical value 6.9×10^?4 obtained by Pauli for pure E2 transition.     

Level structure of the 89-neutron nucleus 153Gd: (I). Levels and gamma-transitions in 153Gd excited in the decay of 153Tb

Investigations of the properties of ¹⁵³Gd excited states populated in ¹⁵³Tb decay were continued. The following measurements were performed: coincidence spectra e^?γ with L41, K93 + L52, K110, K129 + L87 + L88 and K195 + L152 keV conversion electron lines, angular correlations of high energy γ-cascades going through the 109.7 keV level, delayed e^?γ and e^?e^? coincidence spectra to determine the half-lives of 41.5, 93.3, 109.7, 129.1,183.5, 212.0 and 216.1 keV states, R(135°, ± B) parameters of IPAC for the 102–110 and 83–129 keV cascades using ¹⁵³Tb sources implanted into Fe foil.A decay scheme of ¹⁵³Tb containing 50 excited levels is proposed. Their spins, parities, $\text{log}\text{?t}$ and, for low-lying levels, also the mean half-lives have been determined. An estimation of the g-factors of the 109.7 and 129.1 keV levels has been given. On the basis of half-lives of investigated states absolute values of reduced γ-transition probabilities for these states have been calculated. The structure of the ground state of ¹⁵³Gd is discussed.     

A study of 75Se by neutron capture and the SU(3)-SU(5) transition in the quadrupole-phonon representation

The γ and e^? spectra following thermal neutron capture in ⁷⁴Se were studied with curved-crystal, β, and pair spectrometers. Precise energies have been obtained for the transitions and levels at low energies. Two primary E2 transitions were found. The neutron separation energy for ⁷⁵Se was determined as 8027.6 keV. Precise γ-energies following the electron capture decay of ⁷⁵Se were also measured, resulting in precise level energies in ⁷⁵As. The calculation of the energy levels in ⁷⁵Se has been performed in the SU(6) particle-vibrational model (PTQM) and 27 theoretical states have been tentatively assigned to the experimental levels. The spectrum of the core nucleus ⁷⁴Se has been calculated in the SU(6) quadrupolephonon model (TQM). The structure of theoretical states, the relation to SU(3) and SU(5) limits, and potential energy surface are discussed. The E2, M1 and E1 transitions have been calculated in PTQM and compared to the experiment. Also, an overview is presented of theoretical explanations of the I = j, j?1, j?2 anomalous triplet emphasizing the rule with shell-model classification corrected for quadrupole phonons.     

Investigation of levels in59Ni following the β+ decay of59Cu

82s⁵⁹Cu was produced by the⁵⁸Ni(p, γ)⁵⁹Cu reaction using enriched target. The γ-ray spectra following the gb⁺ decay of⁵⁹Cu were studied using two 65 cm³ and 55 cm³ Ge(Li) detectors. Besides confirming all the previously known γ-rays from⁵⁹Cu decay, new γ-rays have been observed and additional direct β⁺ branches to the 1778.8 and 1950keV states of⁵⁹Ni have been identified with estimated log/tft values of 5.6 and 6.7 respectively. Validity of some of the controversial levels around 1700 keV is discussed. The weak γ-ray branches from levels upto 1679.7 keV are compared and found to be in fair agreement with the theoretical predictions of Glaudemans et al.     

Konversionselektronen und Multipolordnungen von Übergängen in Dy165

The spectrum of internal conversion electrons emitted by Dy¹⁶⁵ after thermal neutron capture was measured with the beta spectrometer at the reactor FRM. 225 conversion lines were found between 0 keV and 7 MeV. They correspond to 193 transitions. The multipolarities of most transitions were determined. The result of this measurement is in good agreement with the level scheme proposed bySchult et al. Eighteen additional levels with energies up to 3 MeV are proposed. A new 3/2^?-rotational band with its band head at 1103.30 keV has been disclosed. The level scheme contains 39% of the complete decay of the capture state. The multipolarities of 6 transitions following the beta decay of Dy¹⁶⁵ to Ho¹⁶⁵ are given.     

Study of the 182W(t,p)184W reaction at 20 MeV

The ¹⁸²W(t, p)¹⁸⁴W reaction has been studied at 20 MeV. The outgoing protons were detected in an Elbek broad range magnetic spectrograph. Absolute cross sections and angular distributions were measured. Evidence for inelastic effects in the reaction mechanism was observed for the first excited 2⁺ state, the 3^? level at 1221 keV and the 5⁺ state at 1295 keV. The 0⁺ level at 1002 keV was populated with ≈ 2% the ground state cross section. A 4⁺ level at 1536 keV was observed with ≈ 50% the ground state cross section. Calculations of the absolute (t, p) cross sections to this and other states with known structure resulted in excellent agreement with the measured values.     

Gamma transitions in 59Ni following the β+ decay of 59Cu

The γ-ray decay spectrum of 82 s ⁵⁹Cu produced by the ⁵⁸Ni(p, γ) ⁵⁹Cu reaction has been studied with a 40 cm³ Ge(Li) detector. The number of γ-rays now known for this decay has more than doubled. Additional direct β⁺ branches to the 1679.7($\text{5}\text{2}{}^{\mathrm{?}}$), 2414.8($\text{3}\text{2}{}^{\mathrm{?}}$) and 2681 keV states of ⁵⁹Ni have been identified with log ft values of 5.5, 5.5 and 6.0, respectively. A major change is the reassignment of the 1340.4 keV γ-ray to a 1679.7 → 339.3 keV transition. A limit of log $\text{ft ≧ 6.9}$ is given for the direct feeding of the 1337($\text{7}\text{2}{}^{\mathrm{?}}$) keV state, together with limits for direct population of other energetically available states. The new weak γ-ray branches found for the 878.0, 1301.5 and 1679.7 keV levels are in excellent agreement with the recent theoretical calculations of Glaudemans et al.     

Doublet structure of the first excited state of 71As

The possible multiplet structure of the first-excited state of ⁷¹As has been investigated by the high resolution ⁷⁰Ge(³He, dγ) reaction and the γ-rays emitted in the decay of ⁷¹Se. Both studies reveal a doublet at 143.2 keV and 147.3 keV excitation energies. The existence of this doublet in ⁷¹As brings the low-lying level structure in better resemblance to the heavier odd-A arsenic isotopes.     

The energy of levels of45Sc up to 3 MeV from the44Ca (p, γ)45Sc reaction

The gamma-ray decay of the 1658 keV resonance, which is a member of the isobaric analogues of the 1904 keV 3/2^? level in⁴⁴Ca, has been studied with a Ge(Li) detector. A number of gamma-ray transitions are described and associated with the decay of 15 levels between 1.50 and 3.05 MeV. These observations have made it possible to deduce spin and parity assignments to some of the levels. By comparing excited levels of⁴³Sc and⁴⁵Sc it has been possible to assign certain levels as members of one negative-parity band and two positive-parity bands withK ^π=1/2⁺ and 3/2⁺.     

The beta decay of 18N and T = 2 states of mass 18

The ¹⁸N(β^?)¹⁸O decay was observed via the ⁹Be(¹⁸O, p2α)¹⁸N reaction, utilizing helium-transport techniques and Ge(Li) spectroscopy. In addition to the previously reported β-decay to the ¹⁸O 4456 keV level (J^π = 1^?) branches were observed to levels at excitation energies (in keV) of 1982 (J^π = 2⁺). 5530(2^?), 6198(1^?). 6350(2^? or 1⁺), 6880(0^?), and 7771(2^?). The percentage β-branches, in order of increasing excitation energy, are 3.9 ± 1.5, 54.6 ± 1.0, 3.1 ± 0.4, 1.4 ± 0.2, 2.2 ± 0.3, 14.8 ± 0.8 and 5.0 ± 0.5. respectively, with 15 % assumed on the basis of calculations to proceed to non-γ-emitting states. These measurements allow definite assignments J^π = 1^? for the ¹⁸N ground state and J^π = 0^? for the ¹⁸O 6880 keV state. Additional measurements determine the ¹⁸N half-life to be T_{1 2} = 624 ± 12 ms. A shell-model calculation for mass 18 was carried out in a full 1?ω basis. The predictions for the T = 2 energy level spectrum and for ¹⁸N β-decay are discussed.     

Levels in55Fe from the decay of55Co

The decay of the 18 h⁵⁵Co has been investigated. Twenty-one gamma rays were observed. The following levels in the daughter nucleus⁵⁵Fe were populated in the decay: g.s. (3/2^?), 411.0 keV (1/2^?), 931.5 keV (5/2^?), 1316.7 keV (7/2^?), 1408.7 keV (7/2^?), 2144.1 keV (5/2^?), 2212.5 keV (9/2^?), 2301.4 keV (9/2^?), 2578.2 keV (5/2^±), 2871.9 keV (5/2^?, 7/2^?), 2939.0 keV (5/2^?, 7/2^?) and 3108.6 keV (5/2^?, 7/2^?).