Search results for "decay [resonance]"
showing 10 items of 195 documents
Beta decay of 108Mo and of neighbouring even Mo-isotopes
1995
Abstract A combination of the proton-induced fission of 238 U and the on-line mass separation based on the ion-guide technique has been applied in the study of neutron-rich Mo-isotopes. The decays of 106,108 Mo have been studied by using gamma-, beta-, X-ray and conversion-electron spectroscopy. The decay scheme of 106 Mo has been revised and a beta-decay half-life of 8.73(12) s has been measured for this nucleus. A beta-decay half-life of 1.09(2) s and a decay energy of 5120(40) keV have been measured for 108 Mo. The decay scheme of 108 Mo has been constructed and altogether 29 new transitions have been placed in the decay scheme. The beta-decay strengths of 102,104,106,108 Mo have been de…
Study of the neutron-rich nuclei with $N$ = 21, $^{35}$Si and $^{33}$Mg, by beta decay of $^{35}$Al and $^{33}$Na
2000
Abstract The first information on the level structure of the N =21 nuclei, 35 Si and 33 Mg, has been obtained by the beta decay study of 35 Al and 33 Na, produced by fragmentation of an UC target with 1.4 GeV protons at CERN/ISOLDE. The experimental technique involved β – γ , β – γ – γ , and β –n– γ coincidences, neutron spectra being obtained by time of flight measurements. Gamma detection was made either using large Ge counters or small BaF 2 scintillators (for lifetime measurements). In the case of the 35 Al decay, ( T 1/2 =41.6(2.2) ms), a simple structure has been found for the level scheme of 35 Si ( Z =14, N =21) which has been interpreted with the level sequence : 7/2 − , 3/2 − and …
Measurement of the IAS resonance strength in 23Mg
2000
Abstract Beta decay of 23 Al to excited states in 23 Mg has been studied using low-energy proton and high-energy gamma-ray detection combined with ion-guide-based on-line mass separation. For the first time, a T =3/2 isobaric analogue state, at 7801(2) keV, was observed to decay by both proton and gamma emission, with a proton branching of 0.17(8)%. The deduced resonance strength ωγ =2.2(10) meV is in agreement with upper limits reported from 22 Na(p, γ ) reaction studies. Shell-model calculations are incorporated.
Decay of aπh11/2⊗νh11/2microsecond isomer in61136Pm75
2008
An experiment has been performed to populate several extremely neutron-deficient nuclei around the mass-140 region of the nuclear chart, using a beam of {sup 54}Fe on a {sup 92}Mo target at an energy of 315 MeV. Analysis of these data using recoil-isomer tagging has established that the yrast {pi}h{sub 11/2} x {nu}h{sub 11/2},J{sup {pi}}=(8{sup +}), bandhead state in {sup 136}Pm is isomeric with a half-life of 1.5(1) {mu}s. This isomeric state decays via a 43-keV, probable-E1 transition to a J{sup {pi}}=(7{sup -}) state. Consideration of the theoretical Nilsson orbitals near the Fermi surface suggests that the J{sup {pi}}=(8{sup +}) state has a {nu}h{sub 11/2}[505](11/2){sup -} x {pi}h{sub …
Is the single-state dominance realized in double-β-decay transitions?
1998
In the single-state-dominance hypothesis (SSDH) the decay rate of the two-neutrino double-\ensuremath{\beta} decay to the final ground state is solely determined by virtual single-\ensuremath{\beta}-decay transitions via the ${1}^{+}$ ground state of the intermediate nucleus. A very important consequence the SSDH will be that some of nonaccelerator measurements of double-\ensuremath{\beta}-decay observables could be circumvented by single-\ensuremath{\beta}-decay measurements. To assess the validity of the SSDH, we have carried out a theoretical analysis of all double-\ensuremath{\beta}-decay transitions where the spin-parity of the ground-state of the intermediate nucleus is ${1}^{+}$. The…
β-decay of 113Rh and the observation of 113mPd : Isomer systematics in odd-A palladium isotopes
1993
Abstract Decay of 113Rh to the levels of 113Pd was studied at the IGISOL-facility by means of β-, γ- and conversion-electron spectroscopy. The level scheme of 113Pd was constructed using 33 gamma transitions on the basis of observed γγ-coincidence relations and half-life analysis. A β-decay half-life of (2.80±0.12) s was measured for 113Rh. A new 9 − 2 isomeric state with (0.3 ± 0.1) s half-life and excitation energy 81.3 keV was discovered in 113Pd. This state and the other recently observed low-lying 9 − 2 or 11 − 2 isomeric states in 115,117Pd isotopes are directly populated in proton-induced fission. The decay of these isomers is unusually strongly hindered compared with Weisskopf estim…
Gamow-Teller decay of 118Pd and of the new isotope 120Pd
1993
Abstract With the use of the proton-induced fission of 238 U and the ion guide-fed on-line mass separation, even- A isotopes of palladium with high neutron excess were studied by means of γ-ray and conversion-electron spectroscopy. The decay of 118 Pd was reinvestigated in detail, and evidence for the new isotope 120 Pd, with a half-life T 1 2 = 0.5 ± 0.1 s , was found. As established for 118 Pd and tentatively shown for 120 Pd, the β-decay of these two isotopes proceeds mainly through 0 + → 1 + Gamow-Teller transitions with log ft values between 4.2 and 4.7. The strength of individual transitions has been compared with the predictions of the shell-correction model with a deformed Woods-Sax…
β−decay of the neutron-rich isotope215Pb
2013
This Brief Report reports on the first observation of the β--delayed γ decay of 215Pb, feeding states in 215Bi. The 215Pb beam was produced using resonant laser ionization and mass separated at the ISOLDE-CERN on-line mass separator. This ensured clean identification of the γ rays as belonging to the decay of 215Pb or its β-decay daughters. A half-life of 147(12) s was measured for the 215Pb β decay and a level scheme for the daughter nucleus 215Bi is proposed, resulting in an extended systematics of the excited states of the neutron-rich Bi isotopes.
Gamow-Teller decay of118Pd and of neighbouring even isotopes of palladium
1989
Neutron-rich isotopes of palladium were produced via the fission of238U by 20 MeV protons. These isotopes were selected using the ion guide-fed on-line mass-separator facility IGISOL at Jyvaskyla. Their decays were studied byβ-ray,γ-ray and conversion-electron spectroscopy. For114Pd and116Pd, the decay schemes established previously were confirmed; additionally multipolarities were determined for a few transitions. In the case of118Pd, only an approximate half-life was known from a previous radiochemical experiment. In the present study, 15 gamma transitions were observed, most of which were placed in a decay scheme. The half-life and the decay energy were found to beT1/2=1.9±0.1 s andQβ=4.…
Beta decay of neutron-rich 118Rh and the lowest excited states in 118Pd
2000
Beta decay of a refractory isotope 118Rh produced in symmetric fission and mass separated by the ion guide technique has been applied for the study of low-lying excited states of 118Pd. The yrast band in 118Pd has been observed up to a 6+ state and the lowest states of the asymmetric γ-band have been identified. The measured half-life of 118Rh is (300±60)ms. The systematics of the excited states in neutron-rich Pd-isotopes implies the saturation towards an O(6) symmetry at N = 70.