共查询到20条相似文献,搜索用时 781 毫秒
1.
F.P. Heßberger S. Hofmann I. Kojouharov D. Ackermann S. Antalic P. Cagarda B. Kindler B. Lommel R. Mann A.G. Popeko S. Saro J. Uusitalo A.V. Yeremin 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):335-342
The radioactive decay of 217Pa was investigated by means of α-γ-spectroscopy. Fine structure in the ground-state α-decay was established. Ambiguities
in the fine structure of the α-decay of the previously known isomeric state could be clarified by α-γ-coincidence measurements.
A previously unknown α-transition of E
α = (8306 ± 5) keV was detected and identified by means of delayed α-α- and α-γ-γ-coincidence measurements. A second isomeric
state decaying by α-emission was not observed. The quality of the previously reported data of the α-decay fine structure of
217Th was improved.
Received: 29 April 2002 / Accepted: 17 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: f.p.hessberger@gsi.de
Communicated by J. ?yst? 相似文献
2.
K. Van de Vel A.N. Andreyev R.D. Page H. Kettunen P.T. Greenlees P. Jones R. Julin S. Juutinen H. Kankaanpää A. Keenan P. Kuusiniemi M. Leino M. Muikku P. Nieminen P. Rahkila J. Uusitalo K. Eskola A. Hürstel M. Huyse Y. Le Coz M.B. Smith P. Van Duppen R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):167-171
Gamma rays from excited states of 190Po have been observed using the Jurosphere Ge-detector array coupled to the RITU gas-filled separator. They were associated
with a collective band which from spin 4 onwards resembles the prolate rotational bands known in the isotones 188Pb and 186Hg. This indicates that in 190Po the prolate configuration becomes yrast above I = 2. The experimental results are interpreted in a two-band mixing calculation and are in agreement with α-decay data and
potential energy surface calculations.
Received: 10 January 2003 / Accepted: 19 February 2003 / Published online: 7 May 2003 相似文献
3.
A.N. Andreyev K. Van de Vel A. Barzakh A. De Smet H. De Witte D.V. Fedorov V.N. Fedoseyev S. Franchoo M. Górska M. Huyse Z. Janas U. Köster W. Kurcewicz J. Kurpeta V.I. Mishin K. Partes A. Plochocki P. Van Duppen L. Weissman 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):63-75
Alpha-decay properties of the neutron-deficient isotope 185Pb were studied at the PSB-ISOLDE (CERN) on-line mass separator using the resonance ionisation laser ion source (RILIS). The
nuclei of interest were produced in a 1.4 GeV proton-induced spallation reaction of a uranium graphite target. In contrast
to previous studies, two α-decaying isomeric states were identified in 185Pb. The relative production of the isomers, monitored by their α-counting rates, could be significantly changed when a narrow-bandwidth
laser at the RILIS setup was used to scan through the atomic hyperfine structure. Based on the atomic hyperfine structure
measurements, along with the systematics for heavier odd-mass lead isotopes, the spin and the parity of these states were
interpreted as 3/2- and 13/2+ and their nuclear magnetic moments were deduced. The α-decay energy and half-life value for the I
π = 13/2+ isomer are E
α = 6408(5) keV, T
1/2 = 4.3(2) s, respectively; while for the I
π = 3/2- isomer ( T
1/2 = 6.3(4) s) two α-decays with E
α1 = 6288(5) keV, I
α1 = 56(2)% and E
α2 = 6486(5) keV, I
α2 = 44(2)% were observed. By observing prompt α-γ coincidences new information on the low-lying states in the daughter isotope
181Hg was obtained.
Received: 7 February 2002 / Accepted: 19 February 2002 相似文献
4.
F. Ameil M. Bernas P. Armbruster S. Czajkowski P. Dessagne H. Geissel E. Hanelt C. Kozhuharov C. Miehe C. Donzaud A. Grewe A. Heinz Z. Janas M. de Jong W. Schwab S. Steinhäuser 《The European Physical Journal A - Hadrons and Nuclei》1998,1(3):275-283
The unknown β-decay half-lives of 22 isotopes far off stability (5 < T
Z
< 10) in the region from Ti to Ni were measured at GSI, Darmstadt. The nuclei were produced in a fragmentation reaction of
500 A.MeV 86Kr-projectile impinging on a thick Be target. The isotopes of interest were separated and identified with the fragment separator,
FRS, by a combination of Bρ,Z, and ToF techniques. An additional range separation was performed by a selective implantation
into granular detectors. The spatial and time correlations of the implant with the consecutively detected β-particles were
used to determine the unknown half-lives. For nuclei far off stability, β-decay chains were measured and analyzed as well,
leading to an even more reliable evaluation of the lifetimes. The large discrepancies found between the measured and the theoretical
values emphasize that most recent theoretical work is not an improvement over calculations made almost a decade ago.
Received: 1 October 1997 相似文献
5.
Yu.N. Novikov H. Schatz P. Dendooven R. Béraud Ch. Miehé A.V. Popov D.M. Seliverstov G.K. Vorobjev P. Baumann M.J.G. Borge G. Canchel Ph. Desagne A. Emsallem W. Huang J. Huikari A. Jokinen A. Knipper V. Kolhinen A. Nieminen M. Oinonen H. Penttilä K. Peräjärvi I. Piqueras S. Rinta-Antila J. Szerypo Y. Wang J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2001,11(3):257-261
A careful investigation of the isomeric transition of the long-lived state at 228.5 keV excitation energy in 80Y has been done. The HIGISOL facility at the Jyv?skyl? isochronous cyclotron has been used. We used the electron magnetic
transporter to prepare an appropriate source and to measure the electron spectra in clean background conditions. The measured
internal conversion coefficient αK = 0.50±0.07 allows unambiguous 1- identification for the 228.5 keV first excited isomeric state in 80Y. With a “bare" half-life of 6.8±0.5 s found in this work, this state is strongly populated in the rp-process during X-ray
bursts and has therefore to be taken into account in X-ray burst model calculations. However, because of the similarity of
the β-decay half-lives of isomeric and ground states, we find a maximum reduction in the effective β-decay lifetime of 80Y of only 17±2%. Our results pave the way for a future investigation of the impact of the isomeric state on the “effective"
80Y proton capture rate.
Received: 14 March 2001 / Accepted: 10 July 2001 相似文献
6.
M.N.A. Abdullah M.S. Mahbub S.K. Das A.S.B. Tariq M.A. Uddin A.K. Basak H.M. Sen Gupta F.B. Malik 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):477-486
Full finite-range macroscopic calculations in the distorted-wave Born approximation have been performed using the molecular
and Michel α-nucleus potentials to analyze the angular distributions of cross-sections of the 27Al(α, d)29Si reaction, at 26.5 and 27.2 MeV incident energies, leading to seven transitions up to the excitation energy E
X = 4.08 MeV of the final nucleus. The parameters of the two types of the α-nucleus potentials are determined from the elastic-scattering
data. Both the molecular and Michel potentials, without any adjustment to the parameters needed to fit the elastic-scattering
data, are able in most cases to reproduce, simultaneously, the absolute cross-sections particularly at large angles, where
the previous calculations failed to reproduce by orders of magnitude, and the gross pattern of angular distributions of the
reaction. The deuteron-cluster spectroscopic factors for most of the seven transitions, deduced using the two α-27Al potentials, differ from those obtained in earlier works. The spectroscopic factor for the ground-state transition, deduced
in the present work for the 25.8 MeV data, agrees well with the shell model prediction.
Received: 15 July 2002 / Accepted: 8 August 2002 / Published online: 10 December 2002
RID="a"
ID="a"e-mail: akbasak2001@Yahoo.com
Communicated by G. Orlandini 相似文献
7.
G. Giardina G. Fazio G. Mandaglio M. Manganaro C. Saccá N. V. Eremin A. A. Paskhalov D. A. Smirnov S. P. Maydanyuk V. S. Olkhovsky 《The European Physical Journal A - Hadrons and Nuclei》2008,36(1):31-36
We analyze the bremsstrahlung emission obtained by the α -γ coincidence measurements to investigate on the α -decay dynamics
of the 214
Po nucleus. We performed the experiment using a radioactive 226
Ra source leading, by α -decays, to the 214
Po nucleus, and the apparatus with the Si detector for α -particles, the NaI(Tl) detector able to collect photons with energies
up to about 1 MeV. We compare the experimental data with the quantum-mechanical calculations and find a good agreement between
theory and experiment for photon energies up to 765 keV. In the experimental data of the bremsstrahlung spectrum one can see
the presence of slight oscillations. 相似文献
8.
M.J. López Jiménez M.G. Saint-Laurent J.C. Angélique R. Anne J. Äystö C. Borcea J.M. Daugas D. Guillemaud-Mueller S. Grévy R. Grzywacz A. Jokinen M. Lewitowicz F. Nowacki F. de Oliveira Santos A.N. Ostrowski T. Siiskonen W. Trinder 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):119-122
The β-decay of the T
z = - 2 nucleus 36Ca was studied at the LISE3 magnetic spectrometer at GANIL. Two new proton-emitting states have been detected and the other
nine known βp and βγ transitions have been remeasured with improved resolution. A simulation with the GEANT code has been
applied to this experimental setup. A comparison with shell model calculations is given.
Received: 19 September 2000 / Accepted: 28 February 2001 相似文献
9.
J. Huikari M. Oinonen A. Algora J. Cederkäll S. Courtin P. Dessagne L. Fraile S. Franchoo H. Fynbo W.X. Huang A. Jokinen A. Knipper F. Marechal C. Miehé E. Nacher K. Peräjärvi E. Poirier L. Weissman J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):359-363
The β-decay of 75Sr to its mirror nucleus 75Rb was studied at the ISOLDE PSB facility at CERN by means of β-delayed γ and proton spectroscopy. The decay Q-value and β-delayed γ intensity were measured for the first time. These results, 10.60±0.22 MeV and 4.5+1.9
-0.7%, together with accurate measurements of the β-decay half-life and β-delayed proton branching ratio yielded the Gamow-Teller
strength 0.35±0.05 for the mirror transition. Implications of the results on studies of deformation effects and on the path
of the rapid proton capture process are discussed.
Received: 26 September 2002 / Accepted: 30 October 2002 / Published online: 18 February 2003
RID="a"
ID="a"e-mail: jussi.huikari@phys.jyu.lfi
Communicated by D. Schwalm 相似文献
10.
J. Timár A. Gizon P. Paris J. Genevey J. Gizon F. Hannachi C.F. Liang A. Lopez-Martens J.C. Merdinger B.M. Nyakó B. Weiss L. Zolnai 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):7-10
High spin states of 126La have been populated using the reaction 116Sn+14N at 68 MeV. γ-rays and conversion electrons were detected with the GAREL array. Multipolarities of the lowest-lying in-band
dipole transitions have been determined from the deduced internal conversion coefficients. Experimental B(M1)/B(E2) ratios
have been derived for the bands and compared with calculated values using the D?nau-Frauendorf geometrical model. Configurations
are proposed for the bands comparing them with cranked shell model calculations and on the basis of the measured B(M1)/B(E2)
ratios. The β-decay of 126La has also been revisited. The population of the 126Ba levels gives a probable spin value of five for the decaying high-spin 126La state with T
1/2≈ 64 s which may indicate a signature inversion in the πh11/2νh11/2 band.
Received: 12 October 1999 相似文献
11.
Yu.N. Lobach A.D. Efimov A.A. Pasternak 《The European Physical Journal A - Hadrons and Nuclei》1999,6(2):131-140
Lifetimes of excited states in 110Cd have been measured by the Doppler shift attenuation method in the reaction (α,2nγ) at E
α= 25 MeV. Lifetime values for 8 states and lifetime limits for 3 states were obtained. The band structures of 110Cd have been interpreted in terms of a modified version of the interacting boson model (IBM + 2 q.p.). The calculations explain
well the excitation energies and electromagnetic transition probabilities up to J
π= 16+, except for the 10+
1 state. The structural features are discussed in terms of collective and two quasiparticle excitations.
Received: 20 March 1999 / Revised version: 28 May 1999 相似文献
12.
An effective residual interaction between particles and holes for shell model calculations around 208Pb, derived from the interaction between free nucleons, is compared with the measured properties of proton-hole neutron states
in 208Tl and the interaction between proton holes is adjusted to newly measured level energies in 206Hg. These interaction elements are particularly relevant for neutron-rich nuclei. The adjustment of two mixing elements reproduces
the known γ-decay data in 208Tl.
Received: 2 April 2002 / Accepted: 2 May 2002 相似文献
13.
A. Gizon J. Genevey C.F. Liang P. Paris D. Barnéoud J. Inchaouh I. Penev A. Plochocki 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):309-316
An investigation of low-lying energy levels of 130Pr and 130Ce has been made via β-decay. The radioactive parent nuclei were produced via 94,96Mo + 40Ca reactions at 6.8 MeV/nucleon and transported by a He-jet system. Gamma-γ-t, γ-X-t, γ-e--t coincidence measurements were performed. Internal conversion coefficients have been measured with a magnetic spectrometer.
The new β-decay half-life of 130Nd has been determined to be 21(3) s. A partial level scheme of 130Pr at low-spin has been constructed. The β-decay of 130Pr to 130Ce suggests the existence of three β-instable isomeric states in 130Pr, while only one half-life T
1/2 = 40(4) s has been measured. Based on the present work and low-lying excited states in neighbouring odd-mass nuclei, the
spins and parities of isomeric states in 130Pr are proposed to be 2+, (4,5)+ and (7,8±). The ground state in 130Pr is still undetermined.
Received: 20 August 2001 / Accepted: 6 November 2001 相似文献
14.
G.D. Jones P.A. Butler T.H. Hoare P.M. Jones 《The European Physical Journal A - Hadrons and Nuclei》1998,2(2):129-141
The low spin states of 223Ra have been populated via α-decay from 227Th which was itself produced following β− decay of an 227Ac source. α–γ and α−e
K,L,M angular correlation measurements have been analysed using the correct ground state spins of 227Th(=1/2+) and 223Ra(=3/2+) for the first time.
The analysis has allowed unique Jπ values to be assigned to almost all levels below 400 keV excitation in 223Ra.
Values of (g
K−g
R)/Q
0 have been deduced for several members of the K= 3/2± bands (for the first time in an odd N nucleus in this mass region) allowing estimates of g
K and g
R to be extracted. The values of g
K and g
R are not significantly different for the positive and negative parity band members and tend to support other strong evidence
that stable octupole deformation exists in 223Ra at low excitation energies.
Received: 17 November 1997 / Revised version: 8 January 1998 相似文献
15.
A.N. Andreyev D. Ackermann P. Cagarda J. Gerl F. Heßberger S. Hofmann M. Huyse A. Keenan H. Kettunen A. Kleinböhl A. Lavrentiev M. Leino B. Lommel M. Matos G. Münzenberg C. Moore C.D. O'Leary R.D. Page S. Reshitko S. Saro C. Schlegel H. Schaffner M. Taylor P. Van Duppen L. Weissman R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):381-385
New neutron-deficient isotopes 188,189Po have been produced in the complete fusion reaction of 52Cr ions with a 142Nd target at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the
basis of α-γ and α-conversion electron coincidence measurements and of α-α position and time correlations. In 189Po a ground state to ground state α decay with Eα1= 7540(20) keV, T1/2= 5(1) ms and two fine structure α-decays at Eα2= 7264(15) keV and Eα3= 7316(15) keV have been observed. In 188Po (T1/2= 400+200
−150μs) a ground state to ground state α decay at Eα= 7915(25) keV and a fine structure α decay at Eα= 7350(40) keV have been found. Improved data on the α-decay of 189Bi were obtained.
Received: 15 October 1999 相似文献
16.
Y. Tagaya S. Hashimoto K. Morita Y.H. Pu T. Ariga K. Ohta T. Minemura I. Hisanaga T. Motobayashi T. Nomura 《The European Physical Journal A - Hadrons and Nuclei》1999,5(2):123-125
The α-decay energy and halflife of 195mAt were determined to be 6960±20 keV and 385+69
−51 ms respectively, on the basis of genetic correlations in the 169Tm(36Ar, α6n)195At reaction, while those of 195gAt measured simultaneously were 7105±30 keV and 146+21
−17 ms respectively, reconfirming the previously reported values. A new isotope 199Fr was also produced and identified in the same way in the 169Tm(36Ar, 6n)199Fr reaction, yielding Eα= 7655±40 keV and T1/2= 12+10
−4 ms.
Received: 26 March 1999 相似文献
17.
Synthesis and decay properties of superheavy atoms in nuclear reactions induced by stable and radioactive ion beams 总被引:2,自引:0,他引:2
Yu. Oganessian 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):135-141
This talk consists of two parts. The first one presents the results of investigations performed in 1998-2000 in Dubna on the
synthesis of superheavy nuclei in reactions induced by 48Ca ions. The radioactive decay properties of the nuclei, indicating a considerable increase in the α-decay and spontaneous
fission half-lives of the isotopes of elements 110-116 when approaching the closed neutron shell at N = 184, are given. In the second part the possible ways of advancing into the region of more neutron-rich nuclei, using stable
and radioactive ion beams, are discussed. Since so far no intense radioactive ion beams are available, some experiments with
stable beams are considered as a test for the suggested ideas.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
18.
J. Ekman D. Rudolph C. Fahlander R.J. Charity W. Reviol D.G. Sarantites V. Tomov R.M. Clark M. Cromaz P. Fallon A.O. Macchiavelli M. Carpenter D. Seweryniak 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):13-17
Eighteen previously unknown γ-ray transitions were identified in the T
z = - 1/2 nucleus 51Fe following the fusion-evaporation reaction 32S(28Si,2α1n)51Fe. The level scheme reaches the fully aligned I
π = 27/2- terminating state of the five holes in the f
7/2 shell. The 17/2- state was found to be isomeric, and the lifetime was measured to be 2.87 ns. The mirror symmetry of 51Fe and 51Mn is discussed, and the level scheme of 51Fe is compared to shell-model calculations.
Received: 20 July 2000 / Accepted: 1 August 2000 相似文献
19.
M. Oinonen U. Köster J. Äystö V. Fedoseyev V. Mishin J. Huikari A. Jokinen A. Nieminen K. Peräjärvi A. Knipper G. Walter 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):123-127
Beta-decay of 59Mn has been studied at PSB-ISOLDE, CERN. The intense and pure Mn beam was produced using the Resonance Ionization Laser Ion
Source (RILIS). Based on the measured β-decay rates the ground-state spin and parity are proposed to be J
π = 5/2-. This result is consistent with the systematic trend of the odd-A Mn nuclei and extends the systematics one step further towards the neutron drip line.
Received: 17 November 2000 / Accepted: 16 February 2001 相似文献
20.
M.?Madurga M. J.G.?Borge H. O.U.?Fynbo B.?Jonson G.?Nyman Y.?Prezado K.?Riisager O.?Tengblad IS-?collaboration TONERRE?collaboration 《The European physical journal. Special topics》2007,150(1):137-138
The aim of this work is to find out the origin of the anomalous
resonance in 8Be seen in the reactions through excited states in 9Be.
We have populated the 9Be excited states by β-decay of 9Li.
Energy and direction of the two α particles has been detected and the
neutron spectra reconstructed. In our work we identified the “anomalous resonance" in
8Be observed in several reaction studies
as coming from the decay of the 2.43 and 2.78 MeV states in 9Be.
This anomalous resonance appears when
the two detected α particles are assumed to form a resonance in 8Be.
We argued that the main decaying channels for these two levels in 9Be do not involve
8Be. 相似文献