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1.
The level scheme of97Tc has been investigated by observing theγ-rays following the decay of 2.9-d97Ru.γ-singles andγγ-coincidence measurements were carried out with Ge(Li)-detectors. The time difference of coincident γ-rays was measured as a third parameter. From the coincidence events, the intensities ofγγ-cascades were extracted. The97Ru decay gives rise to 18γ-lines which could be fitted into a level scheme of97Tc consisting of 9 levels. Spin and parity assignments of the levels were made from log(ft) values andγ-ray branching ratios. Discrepancies concerning the energy of the first 3/2? state and the existence of a 946 keV level are discussed. 相似文献
2.
I. N. Borzov S. A. Fayans E. Krömer D. Zawischa 《Zeitschrift für Physik A Hadrons and Nuclei》1974,267(2):117-127
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. 相似文献
3.
Theβ ?-decay of 7.6-min105Tc has been investigated byβ- andγ-ray singles and coincidence measurements. The activities have been produced by thermal-neutron-induced fission of235U or239Pu and subsequent chemical separation of the technetium fraction from the fission product mixture. AQ β-value of 3.2±0.2 MeV has been determined. In a delayed coincidence experiment the lifetime of the first excited state in105Ru at 20.55 keV has been measured to be 340±15 nsec. A level scheme of105Ru is proposed and compared with the results of recent nuclear reaction studies like104Ru(d, p) and104Ru(n, γ). From beta branching ratios to levels in105Ru, ground state spin and parity of 5/2+ can be suggested for105Tc in accordance with the trend observed in neutron rich technetium isotopes. 相似文献
4.
B. Pfeiffer F. Schussler J. Blachot S. J. Feenstra J. van Klinken H. Lawin E. Monnand G. Sadler H. Wollnik K. D. Wünsch JOSEF- LOHENGRIN- OSTIS-collaboration 《Zeitschrift für Physik A Hadrons and Nuclei》1978,287(2):191-210
A study of theβ-decay of neutron-richA=145 fission products was undertaken by the use of the two recoil separators LOHENGRIN and JOSEF and the ISOL-type separator OSTIS. Theβ-decaying isotopes145Ba,145La and145Ce were extensively studied. Level schemes for145La,145Ce and145Pr were deduced fromγ and conversion electron spectra,γγ, X γ delayed andβγ coincidences. TheQ β -values have been measured for the145Ba,145La and145Ce decays. 相似文献
5.
A. Jokinen J. Äystö P. Dendooven K. Eskola Z. Janas P. P. Jauho M. E. Leino J. M. Parmonen H. Penttilä K. Rykaczewski P. Taskinen 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(1):21-28
Neutron-rich nuclides110Ru and112Ru produced in symmetric fission of238U by 20 MeV protons have been studied at the IGISOL facility by means ofβ-ray,γ-ray and conversion electron spectroscopy. A total of 12 and 6γ-transitions were observed in the decays of110Ru and112Ru, respectively. Multipolarities were determined for a few transitions. The beta decay half-life was determined to be 11.6±0.6 s for110Ru and 1.75±0.07 s for112Ru. As a side product, a new value of 2.1±0.3 s for theβ half-life of the112Rh 1+ state was obtained. The decay energy measured with the plastic scintillator was 2.81 ±0.05 MeV for110Ru and 4.52 ±0.08 MeV for112Ru. The beta decay schemes of110Ru and112Ru isotopes indicate that the main fraction of their beta strength resides in two 0+→1+ spin-flip transitions with their logf t values between 4.4 and 4.7. The decay energies and the energies of the 1+ GT states are compared with the macroscopic-microscopic model calculations. The observed GT-strengths are discussed in the framework of the deformed single-particle model. 相似文献
6.
The 20 h95gTc decay to levels of95Mo has been investigated studyingγ-singles andγγ-coincidences. The first excited state of95Mo at 204 keV, previously assumed to be populated in the95m Tc decay only, is found to be fed by aγ-transition of 870 keV deexciting the level at 1074 keV which is populated in the95g Tc decay. More over three newγ-transitions of 477, 786 and 1552 keV deexciting the level at 1552 keV have been found. For the levels at 1074 and 1552 keV the range of possibleJ π assignments could be reduced. 相似文献
7.
J. C. de Lange J. Bron A. van Poelgeest H. Verheul W. B. Ewbank 《Zeitschrift für Physik A Hadrons and Nuclei》1976,279(1):79-91
Decay studies on a number of short-lived odd nuclei in theN=50 region are described. The 59.6-s 93Ru ground state decay was studied in detail for the first time; in these experiments the 10.8-s activity93m Ru was discovered. The91Tc activities were also observed for the first time. The ground state and an isomeric state of this nucleus decay with nearby equal half-lives (3.14 and 3.3-min). The activities91g Mo (16.6-min) and95m Mo (65.1-s) have been reinvestigated. A number ofγ-rays, previously erroneously assigned to the91Mo activities, could be eliminated. A strong similarity is noted for the decay schemes of theN=49 isotones91m Mo and93m Ru. The energy of the 1/2? isomeric state in93Ru and theB(M4)-value of the isomeric transition fit well into the systematics of the previously knownN=49 isotones. 相似文献
8.
Yu Ts Oganessian A. G. Demin M. Hussonnois S. P. Tretyakova Yu P. Kharitonov V. K. Utyonkov I. V. Shirokovsky O. Constantinescu H. Bruchertseifer Yu S. Korotkin 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(2):215-217
In bombarding209Bi and207, 208Pb targets by55Mn and58Fe ions the yields of “cold fusion” reactions have been determined using a sensitive technique for detectingT 1/2≧1 ms spontaneous fission and theα-decay of heavy actinide elements. It has been shown that theA = 263–265 isotopes of element 108, including the even-even isotope264108, undergo mainlyα-decay. The obtained results, together with the known data on the properties of the isotopes of elements 104 and 106, provide evidence for the enhanced stability of theZ=108 nuclei against spontaneous fission. 相似文献
9.
By means of X-γ andγ-γ coincidence measurements of the35Cl+58Ni reaction products, 38γ lines have been identified to be in coincidence with KX(Tc)-rays and assigned to the decay of90Ru. Its half-life of 11±3 s has been deduced from the 154.6 keVγ-decay. The result supports our previous identification of90Ru produced in the same reactions. 相似文献
10.
J. Lange K. R. Baker J. H. Hamilton A. V. Ramayya L. Varnell J. J. Pinajian V. Maruhn-Rezwani 《Zeitschrift für Physik A Hadrons and Nuclei》1981,303(4):321-328
γγ-directional correlations have been measured between the ground state band transitions 6→4, 4→2 and 2→0 and the γ-rays depopulating the levels of the gamma vibrational band and the negative parity states of166Er. Thereby angular momenta could be assigned to the latter states andM2/E1 multipole mixtures determined for the depopulating γ-transitions. TheE2/M1 mixing ratios were obtained for a series ofI γ→I g transitions up toI γ=8+. These are used to investigate the angular momentum dependence of theE2/M1 admixtures. 相似文献
11.
K. Sümmerer N. Kaffrell H. Otto P. Peuser N. Trautmann 《Zeitschrift für Physik A Hadrons and Nuclei》1978,287(3-4):287-297
Theβ ? — andγ-activities of 18.4 min104Tc have been studied with singles and coincidence measurements. Sources were prepared by chemical separation of technetium from the fission products of thermal-neutron-induced fission of235U. A revised level scheme of104Ru up to an excitation energy of 4.26 MeV is proposed. Fromβ-γ coincidence measurements, aQ β-value of 5.62±0.07 MeV has been obtained. 相似文献
12.
H. Bartsch K. Huber U. Kneißl H. Krieger 《Zeitschrift für Physik A Hadrons and Nuclei》1978,285(3):273-281
Short-lived isomers in the nuclei90,92Nb,99Mo,98,100,101Tc and101Ru populated in photonuclear reactions were studied by pulsed beam techniques. Energy and half-life of theγ-rays deexciting the isomeric levels were measured by recording energy-time spectra. The delayedγ-rays andK X-rays were detected by means of an intrinsic Ge-detector of high resolution. From the measured intensity ratios internal conversion coefficients were determined. The multipolarities of the isomeric transitions could be deduced in most cases. A classification of the observed isomers has been tried on the basis of the obtained experimental results and most recent literature data. 相似文献
13.
Z. Árvay T. Fényes J. Gulyás T. Kibédi E. Koltay A. Krasznahorkay S. László V. Paar S. Brant Z. Hloušek 《Zeitschrift für Physik A Hadrons and Nuclei》1981,299(2):139-147
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. 相似文献
14.
E. Andersson P. Herges H. V. Klapdor I. N. Wischnewski 《Zeitschrift für Physik A Hadrons and Nuclei》1981,299(2):105-111
High spin states in108Sn have been investigated using the92Mo(19F,p2nγ)108Sn reaction. In-beam measurements ofγ-γ-coincidences,γ-ray excitation functions andγ-ray angular distributions were performed with Ge(Li)-detectors, one of which had a Nal Compton suppression shield. A level scheme for108Sn has been constructed up to anI π=(14?) state. 相似文献
15.
16.
K. Sümmerer N. Kaffrell E. Stender N. Trautmann K. Brodén G. Skarnemark T. Björnstad I. Haldorsen J.A. Maruhn 《Nuclear Physics A》1980,339(1):74-88
The decay schemes of 36 s 106Tc and 5 s 108Tc have been studied with γ-ray singles and γ-γ coincidence measurements. To separate the technetium nuclides from the fission products of 239Pu, an on-line chemical separation procedure has been developed which is based on multistep chemical separations of liquid phases by fast-rotating centrifuges (“SISAK”). The resulting level schemes of 106Ru and 108Ru, together with those of 102Ru and 104Ru, are interpreted in terms of the generalized collective model of Gneuss and Greiner. The potential-energy surfaces calculated from the spectroscopic data show a trend towards triaxial shapes for the very neutron-rich Ru nuclei. 相似文献
17.
K. Becker G. Jung K. -H. Kobras H. Wollnik B. Pfeiffer 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(2):193-203
γγ-coincidence and angular correlation measurements were performed for transitions in98Sr and98Zr at the on-line-separator facility OSTIS at the Institute Laue-Langevin (ILL) in Grenoble, France. These nuclei were populated byβ-decay from isotopically pure98Rb produced by thermal fission of235U.γγ-angular correlations were measured allowing spin assignments for most levels up to 2 MeV in both nuclei. Listings of angular correlation coefficients and multipole mixing ratios are given. The appearance of shape coexistence is discussed for98Sr and98Zr in the framework of level systematics as well as neutron-separation energies. 相似文献
18.
M. Graefenstedt P. Jürgens U. Keyser F. Münnich F. Schreiber K. Balog T. Winkelmann H. R. Faust 《Zeitschrift für Physik A Hadrons and Nuclei》1989,334(3):239-245
Theβ-decay of neutron-rich fission products with mass numbersA=107, 108 and 109 has been investigated at the mass separator LOHENGRIN of the Institute Laue-Lange-vin (ILL) in Grenoble by measuringβγ-coincidences with a large plastic scintillator telescope and a Ge(I)-detector. Theβ-decay energies of 8 nuclei were obtained from the evaluation of more than 40β-endpoint energies. For the nuclei107 Mo,107Tc,108Tc,109Tc and109Ru, theβ-decay energies were determined for the first time; the experimental error in the decay energy of three daughter nuclei was considerably reduced. In addition, the two-neutron separation energies and the nuclear mass excesses were calculated from these experimentalQ β-values and compared with different mass predictions. 相似文献
19.
From classical in-beam spectroscopy on the106Cd+12C reaction, unambiguousγ-ray assignments have been done for116Xe,116I and116Te nuclei. The ground band levels observed in116Xe have been compared to those of heavier even-even xenon isotopes and to the IBA theoretical predictions. In addition, using the newγ-ray assignments, evaporation cross-sections of the118Xe compound nucleus have been estimated and compared to the evaporation model calculations. 相似文献
20.
T. Karlewski N. Hildebrand M. Brügger N. Kaffrell N. Trautmann G. Herrmann 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(1):55-62
Theβ ?-decay of148,150,152Pr into levels of148,150,152Nd has been studied byγ-singles,γγ-coincidence and for148Pr also byγγ-angular correlation measurements. The praseodymium activities have been obtained by thermal neutron-induced fission of235U followed by on-line mass separation with the helium-jet coupled mass separator HELIOS. Decay schemes for these heaviest praseodymium nuclides are proposed. From the angular correlation measurements spin values for the seven lowest levels of148Nd are deduced. Spin and parity assignments for the lower levels in150,152Nd have been extrapolated from level systematics. 相似文献