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1.
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   

2.
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   

3.
Low-lying states below 500 keV excitation in112In have been investigated via the112Cd(p, nγ) reaction. New levels have been established atE x=206.5keV and 456.1 keV from the measuredγ-ray excitation functions,γ?γ coincidences and the precision measurements of the (p, n) threshold energy of the ground state and of the 206.5 keV state of112In. Spins and parities of the 206.5 keV state (2+) and the 456.1 keV state (3+) and multipolarities and mixing ratios of the deexcitationγ-rays have been determined from the angular distributions and linear polarizations of the deexcitation γ-rays as well as the excitation functions of the residual levels. Possible configurations of the newly-found levels are discussed. Half-lives of two states have been remeasured:T 1/2=15.2±0.1 min for the ground state andT 1/2=20.9±0.1 min for the 156.4 keV (4+) state. The ground stateQ-value for the112Cd(p, n)112 In reaction has been measured to be ?3.376±0.006 MeV.  相似文献   

4.
The level scheme of106Ag has been studied using the103Rh(α,)106Ag and104Pd(α,pnγ)106Ag Reactions. The experimental information is taken fromγ-ray coincidence data using Ge(Li)-Ge(Li) and HPGe-planar Ge(Li) configurations andγ-ray angular distributions. With these measurements 126 γ rays have been assigned to106Ag with 116 deexciting 78 states below 2.26 MeV in excitation. The location of the 8.4-day 6+ isomer is established at 89.63±0.09 keV. Many of the low-lying states are interpreted in terms of a slightly deformed rotor model.  相似文献   

5.
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   

6.
In in-beam (p, p′) experiments, electron and γ-spectra were measured in the electron energy range of 500-1840 keV for102Pd and104Pd, and 600–1580 keV for106Pd. The conversion coefficients of all transitions in this range were obtained with accuracies of about 20%, in some favourable cases 10%. Special attention was given to 0+′-0+ transitions from the two-phonon triplets to the ground states with the following results for the branching ratios 0+′-0+ (ground state) to 0+′-2+ (one-phonon state):102Pd:T k (E0)/T γ (E2)<(2.1±3.6)·10?7 104Pd:T k (E0)/T γ (E2)=(6.0±1.4)·10?5 106Pd:T k (E0)/T γ (E2)=(6.0±2.0)·10?4  相似文献   

7.
Spin assignments have been made to the25Mg levels in theE x=5–6 MeV region fromγ-ray angular distributions measured in the22Ne(α, n y) reaction atE α=8.0 and 8.8 MeV and fromp-γ angular correlations measured in the24Mg(d, p γ) reaction atE d=6 MeV. Unique spin assignments ofJ=7/2, 5/2, 5/2, and 9/2 could be made to the levels atE x=5005, 5511, 5851, and 5967 keV, respectively. Ambigious assignments have been made to the levels atE x=5245, 5524, 5785, 6032 keV (J=11/2, 7/2), 5455 keVJ=13/2, 9/2), and 5738 keV (J=3/2, 5/2). The present data confirm previous assignments ofJ=1/2 to the levels atE x=5108 and 5466 keV, respectively. Lifetime estimates have been obtained, using the Doppler-shift attenuation method, for the levels atE x=5245 keV (τ=30–60 fs), 5785 keV (τ=50–100 fs), 5967 keV (τ=50–100 fs), and 5455 keV (τ>1ps). All other levels in theE x=5–6 MeV region haveτ<60 fs. A breakdown of theK-selection rule has been observed in theγ-decay of some high spin states, indicating a deviation from the strong coupling model.  相似文献   

8.
An investigation of the high spin isomer in151Sm was performed via the150Nd(α, 3nγ) reaction at a projectile energy of 35 MeV. A newγ-transition, 693.6 keV was identified having an exponential delayed component. The transition feeds the 1912 keV state of the negative parity band built on theh 11/2 state. This transition was also observed in coincidence withγ-rays belonging to151Sm in theγ-γ coincidence experiment atE α =37 MeV. A new isomeric state having energyE x =2605.8 keV and half lifeT 1/2=23.1±3.5 ns is proposed.  相似文献   

9.
A combined analysis of the available data on the primaryγ-ray intensities from the113Cd(n, γ) reaction atE n=1.9 and 24.3 keV neutron energies together with the data on113Cd neutron capture cross sections in theE n=3–200 keV energy region was carried out. The neutron strength functions were determined asS n0=(0.260±0.073) 10?4 and Sn1=(5.06±0.67) 10?4. No spin-orbit splitting of thep-wave neutron strength function was found. The energy dependence of theE 1 radiative strength function {ie147-01} was fitted by the Kadmenski-Furman model somewhat better than by a standard Lorentzian. TheM 1 giant resonance parameters were obtained as E G M 1 =8.8±1.6 MeV and Γ G M 1 = 4.7±2.6 MeV. The neutron capture cross section of113Cd from its isomeric state ({ie147-02}=11/2?, E 1 m =263.7 keV) was calculated.  相似文献   

10.
77Se has been investigated by the reaction74Ge(α,) 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).  相似文献   

11.
The level scheme of154Eu has been investigated by means of thermal neutron captureγ-rays and conversion electrons. The high energyγ-ray spectrum from thermal neutron capture in enriched153Eu has been studied in the energy range of 5700 to 6500 keV. Low energyγ radiation has been observed with Ge(Li) and Si(Li) detectors from 5 to 300 keV and conversion electrons have been measured from 15 to 300 keV. Low energy (n, γγ) coincidences and half lives of transitions have been measured. The data, combined with three very recent studies of the 8? isomer decay in154Eu has led to the construction of a level scheme with 12 excited levels. Nuclear Reaction153Eu(n, γ),E n =thermal, measuredE γ ,I γ ,E ce ,I ce ,γγ-coincidence, halflives,154Eu deduced levels.  相似文献   

12.
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   

13.
The studies aimed at decreasing the background of the TGV-2 spectrometer have led to constructive changes in the cryostat and increased the sensitivity of the 32-detector spectrometer. New search for 0νEC/EC, 2νEC/EC) decays of 106Cd was started with ~13.6 g of 106Cd with enrichment of 75%. The evaluation of the experimental data accumulated for 4800 h was performed. Limits (at 90% CL) on the half-lives of 0νEC/EC resonant decay of 106Cd to the 2741 keV excited state of 106Pd (T 1/2 ≥ 6.5 × 1019 y) and on t 2νEC/EC decay to the ground state of 106Pd (0+ → 0+, g.s.) (T 1/2 ≥ 1.7 × 1020 y) were obtained. The limits on the other branches of 106Cd decay—2νEC/EC decay to the 2+, 512 keV and 0 1 + , 1334 keV excited states of 106Pd and 2νβ+β+ and 2νβ+ EC decays of 106Cd to the ground and excited states of 106Pd were improved.  相似文献   

14.
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   

15.
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   

16.
The38Ar levels at Ex=5350, 7289 and 9341 keV have been investigated using the35Cl(α,) reaction at Eα=l4 and 14.5 MeV. From particle-γ-ray angular correlations the spin assignments J(5350)=4, J(7289)=6,4 and J(9341)=8,6,4 have been obtained. Life-time measurements using the Doppler-shift attenuation method yielded τ(9341)=106±25 fs and τ(7289)=77±30 fs, while the lifetime τ(5350)=200±50 fs was known previously. All levels have positive parity and decay by enhanced E2 transitions. Hence we propose that they are the Jπ=4+, 6+ and 8+ members, respectively, of a Kπ=0+ rotational band which has the Ex=3377keV, Jπ=0+ and the 3937 keV, Jπ=2+ levels as further members. The enhancement of inband E2 transitions is 30 ?6 +10 W.u. (4→2), 35 ?14 +30 W.u. (6→4) and 20–36 W.u. (8 → 6), respectively, yielding an average intrinsic quadrupole moment Q0=850 ?125 +200 mb. The moment of inertia is given by h22θ=92 keV. The present data are in good agreement with the predictions of a deformed state in38Ar that coexists with the spherical states.  相似文献   

17.
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).  相似文献   

18.
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, 2) reactions. Spins up to7? were assigned to the observed states. Nuclear Reactions 60Ni(α, 2nγ)62Zn,E α=28–35 MeV and63Cu(p, 2)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.  相似文献   

19.
The lifetimes of several negative-parity states in126,130Xe and132Ba have been determined by means of the generalized centroid-shift method. The reactions124,128Te(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) in126,130Xe and132Ba. Ge detectors. Generalized centroid-shift analysis.  相似文献   

20.
An investigation of double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (at a water equivalent depth of 4800 m) using a TGV-2 spectrometer with 32 detectors. Evaluation of the experimental data accumulated over 12 400 h of measuring ~13.6 g of 106Cd with an enrichment of 75% was performed. New limits (at a confidence level of 90%) on the half-lives of the 0νEC/EC resonant decay of 106Cd to the 2741 keV excited state of 106Pd ? T 1/2 ≥ 1.5 × 1020 y and on 2νEC/EC decay to the ground state of 106Pd (0+ → 0+, g.s.) ? T 1/2 ≥ 3.9 × 1020 y were obtained. The limits of the 2νEC/EC decay of 106Cd to the 2+, 512 keV and 0 1 + , 1334 keV excited states of 106Pd and 2νβ+β+- and the 2νβ+ EC decays of 106Cd to the ground and excited states of 106Pd were improved.  相似文献   

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