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1.
Using gaseous sources of Tc2O7 containing the radioactive isotopes94Tc,95Tc and96Tc, levels at 871.0keV (94Mo), 765.8, 820.6, 947.8, 1074.0keV (95Mo) and 778.3keV (96Mo) have been excited. From the effective cross sections for nuclear resonance scattering and from the lifetimes of the 947.8, 1074.0 and 778.3keV levels known from Coulomb excitation experiments the profiles of theγ-lines have been determined. A broadening of theγ-lines due to Coulomb explosion of the molecules has been observed. Making use of the line profiles, lifetimes ofΤ=(6.4±1.0) ps andΤ=(0.90 ± 0.20) ps have been determined for the 765.8 and 820.6keV levels, respectively. The angular distribution of the resonantly scattered radiation yields an amplitude ratioδ for the mixed M1 E2 765.8keV transition ofδ=0.14 ?0.009 +0.08 . TheB(E2) from a Coulomb excitation experiment and the lifetimeΤ from the present experiment yield ¦δ¦=0.07±0.01 for the 820.6keV transition. 相似文献
2.
T. A. Khan W. D. Lauppe H. A. Selič H. Lawin G. Sadler M. Shaanan K. Sistemich 《Zeitschrift für Physik A Hadrons and Nuclei》1975,275(3):289-296
A windowless Si(Li) electron detector has been used in conjunction with the gas filled fission product separator JOSEF to study totally converted transitions in Zr and Mo isotopes. The existence of twoβ-decay modes in96Y,98Y and100Nb is confirmed. The half-lives of theβ-decaying levels feeding O 2 + states in96Zr and98Zr are 6.0 ± 0.4 sec and 0.60±0.05 sec respectively. A search for other first excited O 2 + states shows that no such states are apparent in100Zr and104Mo. 相似文献
3.
G. Menzen A. Wolf H. Lawin G. Lhersonneau K. Sistemich 《Zeitschrift für Physik A Hadrons and Nuclei》1985,321(4):593-598
Theg factors of the first excited 2+ levels in the neutron-rich nuclei102Mo and104Mo have been studied through the measurement of the perturbed angular correlations for theγ-γ cascades between the 0 2 + -2 1 + -0 1 + level sequences. The results of g=0.42±0.07 for102Mo and ofg= ?0.11 +0.12 for104Mo agree with the prediction of the vibrational-rotational model. In terms of IBA, with the assumption ofN π=3 for the Mo isotopes which takes into consideration a two particle, two-hole excitation across the Z=40 subshell, the proton-bosong factor is deduced to beg π=1.00±0.23. It is shown that this value provides evidence for subshell effects in100Zr. 相似文献
4.
W. Dünnweber C. Borcea P. von Brentano E. Grosse 《Zeitschrift für Physik A Hadrons and Nuclei》1972,254(2):133-141
The decay scheme of the fragmented single neutron states of93Mo up to 3.2 MeV excitation energy is obtained from a92Mo(d,pγ)93Mo coincidence experiment. The total γ-spectrum from92Mo+d shows additional strong γ-decays following the β-decay of93Tc produced by the (d, n) reaction. The decay scheme is discussed in the frame of the particle-core coupling model. The important role of 2+ core excited components inE2 andM1 transitions between states with different angular momentum of the single particle component is pointed out. 相似文献
5.
J. Schoonover H. C. Cheung J. E. Kitching S. K. Mark J. K. P. Lee 《Zeitschrift für Physik A Hadrons and Nuclei》1975,272(1):99-105
The (3He,α) reaction on96Mo and100Mo targets has been studied at a bombarding energy of 18 MeV. Thel n transfer assignments have been made on the basis of angular distribution patterns and on an analysis of the ratios of the experimental and theoretical cross-sections of (3He,α) and (d, t) reactions data leading to the same final states. New states are observed in95Mo at 3373 keV (9/2+); spin and parity assignments are made to levels in99Mo at 1621 keV 7/2+ (9/2+), 1778 keV (5/2?) and 2078 keV (11/2?). 相似文献
6.
The level scheme of the very neutron rich nucleus 106 42 Mo64 has been studied for the first time through theβ decay of106Nb. Six new excited states were observed inγ singles andγ-γ coincidence experiments in addition to the 2+, 4+ and 6+ members of the ground state band. The excitation energies and the deexcitation pattern suggest the interpretation of the levels at 710, 885 and 956 keV as the 2 2 + , 3 1 + and 0 2 + states, respectively. The data support the assumption of a non-axial deformation of106Mo. A half-life of (1.02±0.05) s has been determined for theβ decay of106Nb. 相似文献
7.
P. Strehl 《Zeitschrift für Physik A Hadrons and Nuclei》1970,234(5):416-442
Transitions from the 0+ ground states to 0+ excited states at 7.65 (12C), 6.44 (24Mg), 4.98 and 6.69 (28Si), 3.78 (32S) and 3.35 (40Ca) MeV have been studied with 28 to 60 MeV electrons at scattering angles from 105 to 165°. Matrix elements and transition radii have been deduced, using DWBA-calculations. The monopole excitations can be uniquely distinguished from electric quadrupole excitations by the angular dependence of the cross sections. Some results forE2- andE3-transitions in12C,28Si,32S and40Ca are given, too. 相似文献
8.
M. Weiszflog D. Rudolph C. J. Gross M. K. Kabadiyski K. P. Lieb H. Grawe J. Heese K. -H. Maier J. Eberth S. Skoda 《Zeitschrift für Physik A Hadrons and Nuclei》1993,344(4):395-403
Particle-γ andγ-coincidences of the reaction58Ni(36Ar, 4pn)89Mo have been used to gain more information about high spin states in89Mo and to establish the yrast sequence up to 7.6 MeV excitation energy and probable spin 37/2 ?. Spins and parities were assigned on the basis of DCO-ratios measured with the OSIRIS spectrometer and a large volume Ge detector placed at 162° to the beam. Furthermore, aγ-ray angular distribution experiment was carried out using the reaction58Ni(35Cl, 3pn)89Mo. As in the neighboring isotopes88Mo and90Mo, the positive-parity high-spin states can be grouped into shell model multiplets characterized by increasing seniorities of proton particles and neutron holes in the 1g9/2 shell. The negative-parity states can be explained with one nucleon moving in thep 1/2 orbit. The energies and wave functions of these states have been deduced by means of the shell model code RITSSCHIL. The 2584 keV (21/2+) is an isomeric state the mean life of which has been estimated from delayedγγ-coincidences. 相似文献
9.
Time-of-flight gating techniques have been used to study the decay γ-rays from states excited by inelastic scattering of neutrons from232Th and238U. Neutron energies up to 1900 MeV have been used. From accurate determinations of the γ-ray energies, intensities and thresholds, detailed level and decay schemes have been obtained for232Th and238U. New levels in both nuclei are observed at larger excitations than before and the present work is incompatible with some previously accepted spin and collective band assignments derived from Coulomb excitation studies. 相似文献
10.
H. Seyfarth H. H. Güven B. Kardon W. D. Lauppev G. Lhersonneau K. Sistemich S. Brant N. Kaffrell P. Maier-Komor H. K. Vonach V. Paar D. Vorkapić R. A. Meyer 《Zeitschrift für Physik A Hadrons and Nuclei》1991,339(2):269-278
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. 相似文献
11.
K. P. Lieb T. Hausmann J. J. Kent C. F. Moore 《Zeitschrift für Physik A Hadrons and Nuclei》1968,217(3):213-224
The 2,524 keV 5? state and 2,848 keV3? state in92Mo were excited by inelastic proton scattering going through the 11.80 MeV isobaric analog resonance in93Tc. Angular distributions of the 3?→ 2+ and 5?→ 4+ γ-rays were measured and analyzed in order to obtain the partial waves of the outgoing protons. 相似文献
12.
L. Vannucci U. Abbondanno M. Bettiolo M. Bruno N. Cindro M. D’Agostino P. M. Milazzo R. A. Ricci T. Ritz W. Scheid G. Vannini 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):41-54
Excitation functions and angular distributions of58Ni+58Ni and58Ni+62Ni scattering at energies just above the Coulomb barrier have been measured aroundθ cm=90° in energy stepsΔE cm=0.25 MeV fromE cm ? 110 MeV toE cm ? 120 MeV for58Ni+58Ni and fromE cm ? 110 MeV toE cm ? 118 MeV for58Ni+62Ni. Evidence for structure of non-statistical character has been found in the angle-summed excitation functions; this evidence is corroborated by the analysis of the angular distributions. This is the first time that non-statistical structure in elastic and inelastic scattering is reported with high confidence level for this mass and excitation energy ranges. Attempts are presented to understand the nature of this structure, including the presence of intermediate dinuclear states and virtual states in a potential well. 相似文献
13.
The nilsson-potential parameters for neutrons at A≃-100 and new deformation values for103Mo and105Mo
T. Seo H. Lawin G. Lhersonneau R. A. Meyer G. Menzen K. Sistemich 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(3):393-398
The half-lives of the first excited levels in odd-neutron nuclei103Mo and105Mo have been measured. From these data, values of the deformation parameter of?=0.31±0.05 and 0.29±0.06 for103Mo and105Mo, respectively, have been deduced assuming prolate spheroidal shapes. The present results in combination with previously determined properties of the ground-state bands of these nuclei are used to determineμ, the magnitude of the coefficient of the 12 term, in the Nilsson Hamiltonian, for the new region of deformation atA~-100. 相似文献
14.
F. W. N. de Boer H. J. Wollersheim H. Emling H. Grein E. Grosse W. Spreng G. Eckert Th. W. Elze K. Stelzer Ch. Lauterbach 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):457-466
In a systematic study of nucleon transfer reactions accompanied by Coulomb excitation we have bombarded152Sm,160Gd and232Th with206, 208pb beams at incident energies close to the Coulomb barrier. Particle-gamma coincidence techniques were used to identify excited states of reaction products populated through inelastic scattering and in nucleon transfer reactions. One-neutron stripping and pick-up reactions on152Sm were observed leading to known states of the rotation alignedi 13/2-bands in153Sm and151Sm. In the160Gd+206, 208Pb systems no significant population of low lying states of product nuclei was found in the nucleon-transfer channels. Large cross sections were observed for one- and two-neutron pick-up from232Th at an incident energy of 6.4 MeV/u. Around the grazing angle they are of the same order of magnitude as the cross section measured for inelastic scattering. The results are analyzed in the framework of semiclassical models. 相似文献
15.
W. Fieber K. Bharuth-Ram J. Heese F. Cristancho C. J. Gross K. P. Lieb S. Skoda J. Eberth 《Zeitschrift für Physik A Hadrons and Nuclei》1989,332(4):363-370
Deformation parameters of the positive parity yrast band and negative parity bands in83Zr are deduced from lifetimes andE2/M1 mixing ratios. Lifetimes of high spin states have been determined from recoil distance Doppler shift and Doppler shift attenuation measurements using the54Fe(32S,2pnγ) 83Zr reaction. Ten lifetimes and five lifetimes limits were determined. The positive parity band, built on theg 9/2 K=5/2 orbital has an average deformation ¦β 2¦=0.28(2), and shows a reduction ofE2 transition strengths in the observed backbend region at Iπ≈21/2+. In contrast, theE2 strengths in the negative parity states show a steady increase up to Iπ≈=15/2?. These states are more strongly deformed than the positive parity states (¦β 2¦=0.33(3)). TheE2/M1 mixing ratios show that the negative parity band hasK=3/2 and is prolate, and favour oblate deformation for the positive parity yrast band. In theK=1/2? band theE2 strength of the 7/2?→3/2? transition yields a deformation ¦β 2¦=0.26(5). The band structure is compared with calculations within the Hartree-Fock Bogoliubov cranking model. 相似文献
16.
States in34Ar up to 5.5 MeV excitation energy, populated by the32S(3He,nγ) reaction at 8–12 MeV bombarding energy, have been investigated with the Doppler shift attenuation method,nγ angular correlation andnγγ triple coincidence measurements. For the states at 2.09, 3.29 and 4.52 MeV the lifetimes 200±60 fs, 130±60 fs and 260±80 fs have been found, respectively. Thenγ correlations yielded the spin assignmentsJ μ=(2+) for the level at 4.13 MeV andJ μ=3? for the 4.52 MeV state, and the mixing ratiosδ(3.29→2.09)=?0.12±0.05 andδ(4.13→3.29)=?0.52±0.15. The results are compared with shell model calculations and predictions from the weak coupling unified model. 相似文献
17.
A. Bockisch K. Bharuth-Ram A. M. Kleinfeld K. P. Lieb 《Zeitschrift für Physik A Hadrons and Nuclei》1979,289(2):231-232
Measurements of the reorientation effect for the first excited 2+ states in200, 202, 204Hg were performed by exploiting the dependence of theγ-ray yield on Q2+ for different projectiles. For200Hg, a positive quadrupole moment of Q2=0.96±0.11 eb (for negative interference) or Q2=1.11±0.11 eb (for positive interference) was determined indicating an oblate shape. Small positive Q2 values were also found for202Hg and204Hg. Nine B(E2) values for excitation of the 2+, 2+′ and 4+ states in196–204Hg measured. 相似文献
18.
The excitation of the 24Mg β-band 0+ and 2+ states at 6.43 MeV and 7.35 MeV, respectively, in inelastic hadron scattering has been considered in the collective model where coupling of these states of the states of the ground state band is via a ß-vibration coupled to the static deformation. It is found that coupled channel effects on the 0+ state excitation are rather important and moreover the excitation of the 0+ state can be satisfactorily explained only if a monopole breathing mode form factor is included in addition to the monopole β-vibration form factor. 相似文献
19.
T. Shizuma M. Kidera E. Ideguchi A. Odahara H. Tomura S. Suematsu T. Kuroyanagi Y. Gono S. Mitarai J. Mukai T. Komatsubara K. Furuno K. Heiguchi 《Zeitschrift für Physik A Hadrons and Nuclei》1994,348(1):25-29
Theβ + decay of86Mo has been firstly investigated by means ofβγ spectroscopy. The86Mo nuclei were produced by fusion-evaporation reactions of54 Fe (35Cl, 1 p2n) and58Ni (32S,2p 2n) at beam energies of 103 and 120 MeV, respectively. Threeγ rays of 47.3, 49.8 and 187.0 keV were unambiguously identified to follow theβ + decay of86Mo by results ofXγ andβγ coincidence and cross-bombardment. A half life and a maximumβ +-ray energy of86Mo were determined to be 19.6±1.1 s and 3.9±0.4 MeV, respectively. A decay scheme of86Mo is proposed in this article. Furthermore, a decay of86Nb has been studied using the same combinations of projectiles and targets, and a newβ-decaying isomer86m Nb was observed with a half life of 56.3±8.3 s. 相似文献
20.
K. Shizuma H. Ahrens J. P. Bocquet N. Kaffrell B. D. Kern H. Lawin R. A. Meyer K. Sistemich G. Tittel N. Trautmann 《Zeitschrift für Physik A Hadrons and Nuclei》1984,315(1):65-75
Theβ ? decays of103Nb and105Nb have been studied at the fission product separators JOSEF and LOHENGRIN. Half-lives of (1.5±0.2) s and (2.95±0.06) s, respectively, have been determined for these decays. Fromγ singles andγ-γ coincidence measurements extended level schemes for103Mo and105Mo have been established for the first time. The lowest energy levels of these nuclei are consistent with the interpretation as members of rotational bands built on a 3/2+ [411] Nilsson state. Evidence is presented for the location of the 9/2+ [404] configuration. 相似文献