共查询到20条相似文献,搜索用时 15 毫秒
1.
I. Piqueras M.J.G. Borge Ph. Dessagne J. Giovinazzo A. Huck A. Jokinen A. Knipper C. Longour G. Marguier M. Ramdhane V. Rauch O. Tengblad G. Walter Ch. Miehé 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):313-329
The beta-decay of the N = Z, even-even nucleus 72Kr has been studied at the ISOLDE PSB facility at CERN. Measurements of βγ and βγγ coincidences have enriched the decay scheme
of the daughter nucleus 72Br with 27 new low spin levels. A more precise half-life of T
1/2 = 17.1(2) s has been determined. Strong feeding to the 72Br ground state is established yielding an unambiguous J
π = 1+ assignment for this state. Candidates for the 72Br g.s. wave function are discussed in the framework of a self-consistent deformed mean-field calculation with SG2 Skyrme
force and pairing correlations. A search for beta-delayed particle emission was made and an upper limit of 10-6 for this decay branch obtained. The cumulated experimental level density of 1+ states has been fitted with the constant temperature formula. The comparison indicates that most likely all 1+ levels up to 1.2 MeV have been observed in this investigation. The corresponding nearest-neighbour level spacing does not
follow a Poisson distribution. The Gamow-Teller strength distribution is compared, in terms of nuclear deformation, with different
calculations made in the framework of the quasiparticle random phase approximation.
Received: 7 February 2002 / Accepted: 31 October 2002 / Published online: 6 March 2003
RID="a"
ID="a"e-mail: borge@pinar2.csic.es
RID="b"
ID="b"Present address: Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Le Haut Vigneau, F-33175 Gradignan Cedex, France.
RID="c"
ID="c"Present address: University Mentouri, 25000 Constantine, Algeria.
Communicated by J. ?yst? 相似文献
2.
3.
A. G. Griffiths C. J. Ashworth I. S. Grant J. Rikovska N. J. Stone P. M. Walker W. B. Walters J. P. White 《Hyperfine Interactions》1988,43(1-4):481-488
The nuclear ground state spins of the odd-A Br nuclides75, 77, 79Br with Z=35 are all 3/2−. Nilsson orbital calculations show that the 35th proton occupies the f5/2 [301]3/2− orbital for ε<0.20 and the p3/2 [312]3/2− orbital at larger deformations. The magnetic moments of these two states differ by a factor of two, giving clear evidence
for the magnitude of the ground state deformation. Low Temperature Nuclear Orientation measurements made in Oxford and Bonn
on76, 77gBrFe prepared at ISOLDE, and on line at the SERC Daresbury Laboratory on72, 74m, 75BrFe, have yielded the magnetic moments of these isotopes, using a two non-zero field model with magnetic hyperfine fields of
+81.38(6) T and 26(2) T. The spin of the73Br ground state is also deduced. An interpretation of the ground state configurations of these isotopes is given. 相似文献
4.
C. J. Ashworth T. L. Shaw J. Rikovska N. J. Stone V. R. Green P. M. Walker B. D. D. Singleton I. S. Grant 《Hyperfine Interactions》1988,43(1-4):489-492
The sign of the nuclear magnetic dipole moment of the ground state of122I has been determined to be positive using a novel experimental technique. The technique investigates the asymmetry of positron
emission by detecting the 511 keV gamma-rays produced on the annihilation of the positrons. The method would appear to have
general validity for studying the sign of the magnetic moment in other cases where theβ
+ decay is relatively simple. 相似文献
5.
The two-neutrino double beta decay of96Zr isotope for 0+ → 2+ transition has been studied in the PHFB model. In our earlier work, the reliability of the intrinsic wave functions of96Zr and96Mo isotopes has been established by obtaining an overall agreement between a number of theoretically calculated spectroscopic
properties as well as half-lives of 2vββ decay for 0+ → 0+ transition and the available experimental data. In the present work, the half-life of 2vββ decay for 0+ ar 2+ transition T
1
2/2v
(0+ →2+) has been calculated using the same set of intrinsic wave functions. 相似文献
6.
Magdalena Kowalska 《Hyperfine Interactions》2006,171(1-3):167-172
Collinear laser spectroscopy and β-NMR spectroscopy with optical pumping were applied at ISOLDE/CERN to measure for the first time the magnetic moments of neutron-rich
27Mg, 29Mg, 31Mg and 33Mg, along with the spins of the two latter. The magnetic moment of 27Mg was derived from its hyperfine structure detected in UV fluorescent light, whereas the nuclear magnetic resonance observed
in β-decay asymmetry from a polarised ensemble of nuclei gave the magnetic moment of 29Mg. For 31Mg and 33Mg, the hyperfine structure and nuclear magnetic resonance gave the spin and the magnetic moment. The preliminary results
for 27Mg and 29Mg are consistent with a large neutron shell gap at N=20, whereas data on 31Mg show that for this nucleus N=20 is not a magic number, which is also the case for 33Mg, based on preliminary analysis. Thus, the two latter isotopes belong to the “island of inversion.”
Magdalena Kowalska for the IS 427 collaboration at ISOLDE/CERN. 相似文献
7.
The double-beta-decay experiment NEMO-3 has been taking data since February 2003. The aim of this experiment is to search
for neutrinoless (0 νββ) decay and investigate two neutrino doublebeta decay in seven different isotopically enriched samples (100Mo, 82Se, 48Ca, 96Zr, 116Cd, 130Te, and 150Nd). After analysis of the data corresponding to 3.75 yr, no evidence for 0 νββ decay in the 100Mo and 82Se samples was found. The half-life limits at the 90% C.L. are 1.1 × 1024 and 3.6 × 1023 yr, respectively. Additionally for 0 νββ decay the following limits at the 90% C.L. were obtained, >1.3 × 1022 yr for 48Ca, >9.2 × 1021 yr for 96Zr, and >1.8 × 1022 yr for 150Nd. The 2 νββ decay half-life values were precisely measured for all investigated isotopes. 相似文献
8.
Variation-after-projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for
A=100−108 molybdenum (Mo) isotopes. In this framework, the yrast spectra with J
max
π
≥10+, B(E2) transition probabilities, quadrupole (β2) and hexadecapole (β4) deformation parameters, moment of inertia (I) and square of cranking frequency (ω2) for even-even Mo isotopes have been obtained. The results of the calculation give an indication that it is important to
include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities
in these Mo isotopes. 相似文献
9.
Magdalena Kowalska 《Hyperfine Interactions》2005,162(1-4):109-114
The feasibility of studying the neutron-rich 29Mg, 31Mg, and 33Mg isotopes has been demonstrated with the laser and β-NMR spectroscopy setup at ISOLDE/CERN. The values of the magnetic moment
and the nuclear spin of 31Mg are reported and reveal an intruder ground state. This proves the weakening of N = 20 shell gap and places this nucleus inside the so-called ‘island of inversion.’ The experimental setup and technique,
as well as the results, are presented. 相似文献
10.
M. A. Cardona B. Roussière J. Libert J. Genevey J. Sauvage the ISOCELE ISOLDE Collaborations 《The European Physical Journal A - Hadrons and Nuclei》2007,31(2):141-154
Excited states in 182Os were populated by the β+/EC decay of 182Ir following mass separation. Gamma-ray and conversion electron spectroscopy techniques were employed. Monopole (E0) contributions were determined in transitions populating the ground-state band. A systematic study of the low-spin structures
in the Os isotopes is presented and a detailed analysis in the framework of a microscopic configuration mixing approach is
performed. 相似文献
11.
The 0+ ↔ 0− first-forbidden β decay transitions have been investigated for some spherical nuclei. The theoretical framework is based on a proton-neutron
quasiparticle random phase approximation (pnQRPA). The Woods-Saxon potential basis has been used in our calculations. The
transition probabilities have been calculated within the ξ approximation. The relativistic β moment matrix element has been calculated both directly without any assumption and assuming that it is proportional to the
non-relativistic one. 相似文献
12.
Ch. Miehé Ph. Dessagne Ch. Pujol G. Walter B. Jonson M. Lindroos 《The European Physical Journal A - Hadrons and Nuclei》1999,5(2):143-150
The β+– electron capture decay of 73Kr, produced at the ISOLDE CERN facility, has been studied by β-delayed proton and gamma emission. The established decay scheme
involves 15 up to now unreported gamma emitting levels in 73Br. The total proton branching ratio has been measured to be 0.0025 ± 0.0003. From this work, a spin and parity 3/2− is assigned to the 73Kr ground state, on the basis of the allowed β branch to the 73Br Jπ= 1/2− ground state and the feeding of the 5/2+ level located at 286 keV in 73Br.
Received: 17 September 1998 / Revised version: 25 January 1999 相似文献
13.
Th. Hilberath St. Becker G. Bollen M. Gerber H. -J. Kluge U. Krönert G. Passler 《Hyperfine Interactions》1990,59(1-4):97-100
The hyperfine structure and the isotope shift of very neutron-deficient Au and Pt isotopes have been determined at the on-line
isotope separator ISOLDE/CERN by resonance ionization mass spectroscopy combined with pulsed-laser induced desorption of the
implanted radioactive sample. The changes of the mean-square charge radii were determined for the isotopes184Au (T1/2=53 s) and183Au (T1/2=42 s) as well as for 15 isotopes of platinum in the range between198Pt (stable) and183Pt (T1/2=6.5 min). The strong deformation of185Au (|β2|≃0.25) persits down to183Au. In183Pt nearly the same value of |β2| is reached but the deformation is build up rather smoothly in contrast to the neighbouring isotopes of gold and mercury.
The magnetic moment of183Pt was found to be μ1=+0.51(3)μ
N
. 相似文献
14.
H. Postma B. Kastelein N. Severijns D. Vandeplassche J. Vanhaverbeke L. Vanneste E. van Walle J. Wouters J. van Klinken 《Hyperfine Interactions》1989,52(1):79-88
Gamma-ray anisotropy measurements have been carried out with brute-force oriented178m
2Hf (16+) to derive its magnetic moment 7.26 (±0.16; +0.2/−0) nm and E2/M1 mixing ratios of some γ-transitions observed in the decay
of this isomer. This magnetic moment is in agreement with an earlier proposed four-quasi-particle configuration. The magnetic
moment of the 8− isomer at 1147.7 keV (4.0 s) is estimated to be between 1.4 and 5.3 nm, which confirms mixing of the {p[514]9/2 +p[404]7/2}8− and {n[514]7/2+n[624]9/2}8− configurations, which summed together give the 16+ isomer. 相似文献
15.
The temperature dependence of the precession of the angular correlation of decay gamma rays from swift150Sm (2
1
+
) ions traversing a gadolinium foil has been found to be proportional to the foil magnetization, supporting the assertion
that the transient hyperfine magnetic field acting on these ions is proportional to the magnetization of the hosts (iron or
gadolinium). Similar experiments on194Pt (2
1
+
) ions traversing iron and gadolinium foils are consistent with both the magnetic moment obtained from Rutgers experiments
on iron and with a hyperfine field at Pt ions larger for gadolinium than for iron foils, in agreement with the Chalk River
parametrization for heavy nuclei traversing gadolinium foils. Finally, the magnetic moments of the 2
1
+
states in144–150Nd,145,150Sm and152Gd have been measured. These data support the evidence of shell closure atZ=64 forN≤88 andZ=50 forN>90. 相似文献
16.
Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)
Zhou Dongmei Zheng Yongnan Du Enpeng Xu Yongjun Zhu Jiazheng Yuan Daqing Wang Zhiqiang Luo Hailong Zuo Yi Ma Ruigang Duan Xiao M. Mihara M. Fukuda K. Matsuta T. Minamisono Zhu Shengyun 《中国科学G辑(英文版)》2004,47(5):531-539
The spin polarized β-emitting nuclei12B (I
π=1+,T
1/2=20.18 ms) were produced by the nuclear reaction11B(d, p)12B and by the selection technique of the incident deuteron energy and the12B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei12B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment
of12B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift. 相似文献
17.
S. Singh R. Chandra P. K. Rath P. K. Raina J. G. Hirsch 《The European Physical Journal A - Hadrons and Nuclei》2007,33(4):375-388
The two-neutrino double-beta decay of 124, 126Xe , 128, 130Te , 130, 132Ba and 150Nd isotopes is studied in the Projected Hartree-Fock-Bogoliubov (PHFB) model. Theoretical 2ν β-β- half-lives of 128, 130Te , and 150Nd isotopes, and 2ν β+β+ , 2ν β+
EC and 2ν ECEC for 124, 126Xe and 130, 132Ba nuclei are presented. Calculated quadrupolar transition probabilities B(E2 : 0+ → 2+) , static quadrupole moments and g -factors in the parent and daughter nuclei reproduce the experimental information, validating the reliability of the model
wave functions. The anticorrelation between nuclear deformation and the nuclear transition matrix element M
2ν is confirmed. 相似文献
18.
F. P. Heßberger S. Antalic B. Streicher S. Hofmann D. Ackermann B. Kindler I. Kojouharov P. Kuusiniemi M. Leino B. Lommel R. Mann K. Nishio S. Saro B. Sulignano 《The European Physical Journal A - Hadrons and Nuclei》2005,26(2):233-239
The decay of odd-mass mendelevium isotopes ( A = 247-255) has been studied by means of α-γ spectroscopy. Strong evidence for a small α branch in the decay of 253Md was found. γ lines in coincidence with α-decays of 247, 249, 251, 253Md have been observed for the first time. Levels in the einsteinium daughter nuclei were assigned on the basis of α-γ coincidence
measurements. An energy systematics of the 7/2-[514] Nilsson level could be established, showing a correlation with the deformation parameter β2 of the corresponding nuclei. The results are compared with theoretical predictions 相似文献
19.
M. Seliverstov A. Andreyev N. Barré H. De Witte D. Fedorov V. Fedoseyev S. Franchoo J. Genevey G. Huber M. Huyse U. Köster P. Kunz S. Lesher B. Marsh B. Roussière J. Sauvage P. Van Duppen Yu. Volkov 《Hyperfine Interactions》2006,171(1-3):225-231
Mean-square charge radii and magnetic moments have been measured for the neutron deficient lead isotopes, 182–190Pb. The measurement was performed at the ISOLDE online mass separator, using the in-source resonance ionization spectroscopy
technique. The wavelength of the first excitation step for the resonance ionization laser ion source (RILIS) was scanned over
the resonance(s) whilst the α- and γ-ray spectra from the decay of the Pb isotopes were recorded as a function of the wavelength. The isotope shift and, in the
case of odd-A isotopes, the hyperfine splitting were deduced. The rms-charge radii of the very neutron deficient Pb isotopes follow the
smooth trend of the heavier isotopes. This finding indicates a spherical shape for the lead ground states at the neutron mid-shell
(N = 104), where the excitation energy of the oblate 0+ state in the even isotopes reaches its minimum. 相似文献
20.
J. Prinz I. Berkes P. Herzog B. Hlimi M. De Jesus M. Massaq I. Romanski 《Hyperfine Interactions》1992,75(1-4):275-282
First experiments in the systematic study of the structure of ground states and isomeric states of Br isotopes as function
of neutron number at ISOLDE, CERN are reported. The isotopes74g.74m,77,78,84g,84mBr have been implanted into iron and studied with the techniques of low temperature nuclear orientation and nuclear magnetic
resonance of oriented nuclei (NMR/ON). The experiments were performed with the NICOLE on-line nuclear orientation set-up using
the isotope separator ISOLDE-3. NMR/ON experiments were successful for74mBr with continuous on-line implantation and for77Br. Using as value of the hyperfine field Bhf(BrFe)=+81.3S (3) T we obtain |g (74mBr)|=0.455 (3) and |g (77Br)|=0.6492 (3). Static nuclear orientation data have been measured for all above mentioned isotopes. From these data we derive
|μ(78Br, I=1)|=0.13 (3) and |μ(84gBr, I=2)|=1.9 (7). The results are discussed within the systematics of the bromine isotopes. 相似文献