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1.
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.  相似文献   

2.
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.  相似文献   

3.
A spectroscopy study has been made of the62Ni(p,nγ)62Cu reaction, allowing levels in62Cu to be investigated up toE x=1.843 MeV. Ten new levels and eleven spins are given.  相似文献   

4.
Resonances in the reaction60Ni(p, γ)61Cu have been studied in the proton energy rangesE p=1840–1880 keV and 2220–2300 keV. Decay schemes and branching ratios have been determined for a number of resonances, three of which are identified as analogue fragments of the 283 keV (1/2?) and 656 keV (3/2?) states in61Ni. The split analogue components of the 283 keV state atE x≈6.6 MeV are seen to decay significantly to a group of states in the region of excitation 3–4 MeV. Gamma ray angular distributions yield the following resonance spins:E p=2248 keV,J=3/2;E p=2263 keV,J=5/2. Also, the61Cu ground stateβ + decay to parent levels in61Ni has been compared to the respective analogue stateM1 gamma decay to the61Cu ground state.  相似文献   

5.
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 h11/2 proton orbital. Nuclear Reactions:153Eu(α, 4)153Tb,E=45–55 MeV;150Sm(10B, 5)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.  相似文献   

6.
α-particle and proton spectra in coincidence with the 4.44 MeVγ-ray from the12C first excited state have been taken atE τ MeV. Several states in13N and16O are seen to contribute to the decay sequenceα?p andp?α respectively. Estimates are given for the branching of these two decay modes and for a possible simultaneous break-up.  相似文献   

7.
The gamma decay mode and the possible spin values of the second excited state of48Ca (E x =4.28 MeV) were investigated by studying the48Ca(p, p′γ) reaction at an incident proton energy of 10.30 MeV. No ground state gamma transition was observed. The analysis of thep 2 -γ angular correlation — using method II of Litherland and Ferguson — supports the spin assignmentI=0 for this level and excludes all spin values higher thanI=1.  相似文献   

8.
The68Ga nucleus has been studied via the reactions65Cu(α, nγ)68Ga atE α=12–21 MeV and66Zn(α, p nγ)68Ga atE α=25–40 MeV. The level scheme has been established by means of relative yield functions, electronic timing measurements, prompt and delayedγ-γ coincidences, angular distributions and directional orientation coÏncidences. Spins up to 11+ were assigned to levels up to 4 MeV excitation and the higher ones were interpreted by coupling a67Ga core with a (v 1 g9/2) neutron.  相似文献   

9.
The proton capture cross sections for the reaction63Cu(p, γi)64Zn leading to several resolved states in the64Zn nucleus have been measured forE p =6.5–11.0 MeV. The excitation functions have been reproduced by the combined CN and DSD models. The extracted spectroscopic factors compared with those derived from the stripping reaction are found to show a distinct correlation.  相似文献   

10.
The level structure and the decay properties of low-lying levels in 63Cu have been investigated via the 60Ni(α, pγ)63Cu reaction at Eα = 11.7MeV. Using a Ge(Li) detector, the correlations of twenty-five primary γ-rays in coincidence with protons, stopped in an annular detector at approximatively 180° with respect to the beam direction, were measured. From these measurements, branching ratios, γ-ray mixing ratios and spin assignments have been obtained for most of the levels up to 2.4 MeV excitation.  相似文献   

11.
The two short-lived isomeric states in112In have been reinvestigated by means of the112Cd(d, 2n) and109Ag (α, n) reactions. Measurements of delayed X- andγ-ray, lifetime and TDPAD spectra have been performed. A 6.32(3) keVγ-ray has been identified in the isomeric decay and anM1 multipolarity has been assigned to it on the basis of the measured internal conversion coefficients:α L =196(39) andα tot=231(35). TheE1+M2(δ =+0.24(4)) andE2 multipolarities have been determined for the 263 and 188 keV transitions deexciting the 8?(T 1/2=2.82(2) μs) and 7+ (T 1/2=0.93(2) μs) isomeric states, respectively. A revised isomeric decay scheme is presented.  相似文献   

12.
Excitation functions for the18O(p,n)18F reaction were measured at bombarding energiesE p=4.6 to 6.6 MeV. In and near two resonances of the yield curves atE p=5.622 and 6.061 MeV, angular distributions were measured with neutron time-of-flight techniques. The strong neutron decay to theT=1 state in18F and the similarity of the18O(p,n) and18O(n,n) yield curves give good evidence that the structures in the18O(p,n) yield curve arise from the formation ofT=3/2 states in19F. A two-level-analysis does not give satisfactory fits to the strongly asymmetric angular distributions.  相似文献   

13.
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,)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).  相似文献   

14.
The isomer213mRa was produced by the reaction209Bi(10B, 6n), as well as by bombardments of12C on Pb isotopes,14N on Bi, and16O on natural Hg, with projectile energies in the range 60–100 MeV. The isomer decays with a halflife of 2.1 ms both via gamma internal transitions and via alpha branching to levels in209Rn. A level scheme is proposed in which the isomeric state is assigned as either 17/2? or 13/2+ with shell-model configurations either of theh 9/2 protons coupled to ap 1/2 neutron hole, or of an uncoupledi 13/2 neutron hole. On the basis of alpha decay rate predictions from the new Fliessbach theory, the 17/2? isomeric assignment is to be preferred. Phys. Abstracts classifications 4.200–4.375 E [Radioactivity213m Ra [from209Bi(10B, 6n),204-6Pb(12C, 3n–5n) etc.,E=60–100 MeV]; measuredE α ,E γ ,I α ,I γ ,I x ,γγ-coin,-coin,α K,T 1/2.213Ra,209Rn deduced levels,J, π,γ-multipolarity.]  相似文献   

15.
A search for high-spin states in28Si has been performed byn?y coincidence measurements in the25Mg(α,nγy) reaction atE α=14 and 15.5 MeV. Spin-parity assignments of the observed levels were obtained fromn?γ angular correlation and lifetime measurements atE α=14.5 MeV. Theγ-decay of the 9,164 keV level was investigated separately with the27Al(p, γ) reaction at theE p=2,160 and 2,312 keV resonances. Rotational bands withK π=3? (comprising levels atE x=6,879, 8,413, 10,188 and 12,204 keV),K π =5? (comprising levels atE x=9,702, 11,577 and 13,741 keV) andK π=0+ (comprising levels atE x=6,691, 7,381, 9,164 and 11,509 keV) were observed. The finding of the latter band supports the idea of coexisting oblate and prolate shapes in28Si. A level at 14,643 keV excitation energy has the properties of theI π=8+ member of the ground state band. There are additional positive-parity high-spin states which do not fit into rotational bands. All types of positive-parity states are well accounted for by shell model calculations.  相似文献   

16.
The decay scheme of112Cd has been studied by γ-ray spectroscopy with the110Pd(α, 2nγ) reaction. Spin and parity assignments were made on the basis of coincidence measurements, angular distributions and excitation functions. Twelve new energy levels were established. A vibrational-like positive-parity band up to spin 8+ and a negativeparity side band 5?, (7?), (9?) were found. For the negative-parity states a (vj, vh11/2) configuration is suggested. Nuclear Reactions:110Pd(α,2nγ),E α =15–22.5 MeV; measuredE γ ,E γ , (E,E γ ),E γ (θ),γ-γ- coincidence;112Cd deduced levels,J; enriched target.  相似文献   

17.
The24Mg(α, p γ) reaction has been studied atα-particle energies of 13, 15, and 15.2 MeV. Using method II of Litherland and Ferguson spin assignments or restrictions thereof could be made to the27Al levels atE x =5500 keV (I=11/2, 7/2), 6950 keV (I=11/2, 7/2), 7226 keV (I=9/2), 7286 keV (I=9/2–13/2), 7399 keV (I=11/2, 7/2) and 7443 keV (I=13/2, 9/2). Using the Doppler-shift attenuation method a lifetimeτ=20–50 fs was obtained for theE x =7399 keV level and a limitτ<20 fs for the levels atE x =7443, 7286, 7226, 6950, 6718, and 6287 keV, respectively. Further spin assignments in27Al were obtained by a study of the26Mg(p, γ) reaction at the Ep=2174 keV resonance. Fromγ-ray angular distributions the resonance spin was determined as I=9/2 (previous assignmentI=7/2) and the spin of theE x =5959 keV level was determined asI=7/2. Tentative spin assignments were made to the levels atE x =6537 keV (I=7/2) and 6718 keV (I=9/2). From the combined evidence of the24Mg(α, p) and26Mg(p, γ) reactions the spin of the 6287 keV level was found to beI=7/2. The results are compared with shell model calculations and the Nilsson model.  相似文献   

18.
Mean lives and excitation energies of the lowest levels in64Ni,66Zn and68Zn were measured with the aid of the (α, α′γ) and (α, pγ) reactions. The γ-rays were detected in coincidence with the outgoing particles. The following mean lives were determined from DSA measurements: 400 ± 150 fs for the level at Ex = 1.35 MeV in 64Ni; 270 ± 100, 210 ± 110, 330 ± 200, 80 ± 70 fs for the levels at Ex = 1.87, 2.45, 2.83, 2.94 MeV in 66Zn, and 1300 ± 300, > 160, 600 ± 200 fs for the levels at Ex = 1.08, 1.89 and 2.76 MeV in 68Zn, respectively.  相似文献   

19.
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.  相似文献   

20.
Recent scrutiny of the relevant data available at present on x-ray satellite spectra in theK, L andM regions revealed the existence of two new satellite pairsα″α′ andα″α′ 3 in the satellite group, three pairsα′ 2 α″,α′ 2 αVI andα? α IV in the satellite group, two 2 satellite groups; viz.,β 2 (b) (β 2 I ,β 2 II β 2 (c) ) andβ 2 (c) (β 2 I β 2 II ), two pairsγ1 γ2 andγ1 γ2′ in the satellite group and also a pairβ II β III in the satellites, which are all found to be governed by the screening doublet relationship,Δ(v/R)1/2=constant.  相似文献   

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