共查询到20条相似文献,搜索用时 31 毫秒
1.
I. Romanski I. Berkes D. E. Brown M. De Jesus R. Eder I. S. Grant E. Hagn P. Harding P. Herzog B. Hinfurtner B. Kastelein H. Postma J. Prinz P. Richards K. Schlösser N. J. Stone L. Vanneste E. Zech Nicole Isolde 《Hyperfine Interactions》1992,75(1-4):457-470
The methods of time-resolved and time-integral on-line nuclear orientation have been applied to study short lived nuclei with
the NICOLE facility (Nuclear Implantation into Cold On-Line Equipment) at ISOLDE-3 in CERN using beams of182–186Hg. The half-lives in these decay chains are of the order of seconds and therefore comparable to the spin-lattice relaxation
times of the nuclei in iron. As the relaxation rate depends strongly on the g-factor, g-factors of nuclei in the decay chains
can be deduced from the observation of the time evolution of γ-ray anisotropy. Using this technique the existence of an isomer
in184Au has been found and the g-factors of184Au,184mAu and182Au have been determined. Accurate half-lives have been extracted from the data.
Time-integral nuclear orientation has been observed for short lived as well as longer lived isotopes of the Hg decay chains.
From these measurements, after proper correction for incomplete relaxation, the magnetic moments of183mPt,183Ir and182Ir have been derived.
The applicability of the time-resolved nuclear orientation technique for nuclei far from stability and its possible limitations
is discussed. 相似文献
2.
The magnetic hyperfine field of Se in nickel was measured by means of the time-differential perturbed angular correlation
(DPAC) technique, using the 755–250 keV γ-ray cascade fed in the decay of77Br. A value ofB
hf(NiSe)=+15.11(35) T was obtained at room temperature. The half-life of the 250 keV state and the anisotropy of the 755–250 keV
cascade were found to beT
1/2=9.68(6) ns andA
22=−0.454(9), respectively. 相似文献
3.
Z.G. Gan Z. Qin J.S. Guo L.J. Shi H.Y. Liu T.R. Guo X.G. Lei R.C. Ma W.X. Huang S.G. Yuan X.Q. Zhang G.M. Jin 《The European Physical Journal A - Hadrons and Nuclei》1999,6(1):59-61
The decay of 131Pm has been investigated by means of γ-ray spectroscopy. The 131Pm nuclei were produced by fusion-evaporation reaction of 106Cd(32S,3p4n) at the beam energy of 170 MeV. A helium-jet technique and a tape transport system were used to collect the activities
and transfer them to a detecting position for X and γ rays measurement. Two γ rays of 185.0 and 220.0 keV were unambiguously
identified to follow the β+ decay of 131Pm by results of X-γ and γ–γ coincidence. A growth-decay feature of the decay curve for 87.8 keV γ-ray of 131Nd confirmed the production of 131Pm nuclei. The half-life of 131Pm was measured to be 6.3 ± 0.8 s. A partial decay scheme of 131Pm is proposed on the basis of X-γ and γ–γ coincidence data in this experiment and the known structure information deduced
from in-beam experiments of the daughter nucleus 131Nd.
Received: 11 January 1999 / Revised version: 20 May 1999 相似文献
4.
Z. Z. Akselrod G. A. Denisenko B. A. Komissarova L. N. Kryukova G. K. Ryasny A. A. Sorokin L. G. Shpin’kova 《Hyperfine Interactions》1990,61(1-4):1147-1150
Results of TDPAC studies of hyperfine interaction in high temperature superconducting ceramics are reported. The γ-ray cascade
of 329–487 keV in140Ce excited in the decay of140La in La2-xSrxCuO4 samples (x=0 and 0.15), and 133–482 keV cascade in181Ta excited in the decay of181Hf in YBa2Cu3O7-δ samples were used. The procedure of introducing radioactive181Hf into the ceramics is described and indirect evidence for the occupation of Cu sites by the181Hf-181Ta probe is presented. 相似文献
5.
Z. Plajner I. Řezanka A. Špalek J. Frána M. Josovič M. Fišer 《Czechoslovak Journal of Physics》1970,20(8):917-925
Multipolarities of 130, 279, and 409 keV transitions in the decay of197mHg have been determined by magnetic electron and gamma-ray spectroscopy. The multipolarities of other transitions have been verified. The results are compared with core excitation, Alaga and Ialongo and pairing-plus-quadrupole calculations. 相似文献
6.
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
7.
Nuclear magnetic resonance on oriented nuclei has been detected for the first time via the destruction of the anisotropy of characteristic Lx-rays. The new method can be applied to isomeric states which decay only via highly converted transitions, for which the standard NMR-ON technique — detection of NMR via the anisotropy of -rays — is not applicable. The X-NMR-ON technique has been used to measure the magnetic hyperfine splitting of193mpt (I=1322+; E=149.8 keV; T1/2= 4.3 d) to be ¦ g
NBHF/h¦=111.3 (3) MHz. with the known hyperfine field of –1280(27) kG the magnetic moment of193mpt is deduced to be ¦¦=0.7417(14) N. This magnetic moment differs strongly from the known magnetic moments of the 13/2+ isomeric states in Hg and Pb and195mPt. 相似文献
8.
The magnetic hyperfine splitting frequency of 82BrNi in an external magnetic field of 0.2 T has been measured by NMR-ON method at 8 mK. The centre of resonance frequency
was determined to be 18.7(2) MHz. With the known g-factor of g(82Br)= 0.3254(1), the hyperfine field of 82BrNi was deduced as Bhf(82BrNi)= 7.34(8) T. The measured value is compared with the calculated value based on band structure using bonding states.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Goto J. Ohya S. Ohtsubo T. Kawamura Y. Muto S. Nishimura K. Tanigaki M. Taniguchi A. Ohkubo Y. Kawase Y. 《Hyperfine Interactions》2001,136(3-8):561-566
Low-temperature nuclear orientation (LTNO) experiments were performed on 151Pm implanted into iron and 147Nd implanted into nickel. The γ-ray anisotropy measurements yielded values of the magnetic hyperfine field and the substitutional
fractions of these ions in the host metals. An observed discrepancy between the substitutional fractions obtained from the
91 keV and 531 keV data on 147NdNi is briefly discussed.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
10.
Nuclear orientation techniques have been used to derive the magnetic dipole moments of the three 11/2? isomers of193, 195, 197Au. The derived q-factors are: 1.121(17) for193mAu, 1.122(17) for195mAu, and 1.17(7) for197mAu. For the first two isotopes, the NMR-ON method could be used. In the latter case, the temperature dependence of nuclear orientation has been used. 相似文献
11.
F. Ibrahim J. Genevey E. Cottereau A. Gizon A. Knipper F. Le Blanc G. Marguier J. Obert J. Oms J.C. Putaux B. Roussière J. Sauvage A. Wojtasiewicz 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):139-143
Low-lying states in the odd-odd light gold isotope 182Au have been populated by the β+/EC decay of the 182Hg nuclei. Level energies, spin and parity values were determined using on-line γ-ray and e- spectroscopy measurements. No isomeric state with a long half-life was found in the 182Au nucleus. Spin and parity I
π = 2+ can be very likely assigned to the 182Au ground state.
Received: 19 December 2000 / Accepted: 28 February 2001 相似文献
12.
《The European Physical Journal C - Particles and Fields》2008,54(1):61-72
Results of background measurements with a prototype of the Borexino detector were used to search for 478 keV solar axions
emitted in the M1-transitions of 7Li*. The Compton conversion of axion to a photon A+e→e+γ, axioelectric effect A+e+Z→e+Z, decay of axion in two photons A→2γ and
Primakoff conversion on nuclei A+Z→γ+Z are considered. The upper limit on constants of interaction of axion with electrons,
photons and nucleons – gAegAN≤(1.0–2.4)×10-10 at mA≤450 keV and gAγgAN≤5×10-9 GeV-1 at mA≤10 keV are obtained (90%c.l.). For heavy axions with mass at 100<mA<400 keV the limits gAe<(0.7–2.0)×10-8 and gAγ<10-9–10-8 are obtained in assumption that gAN depends on mA as for KSVZ axion model. These limits are stronger than obtained in previous laboratory-based experiments using nuclear reactor
and artificial radioactive sources.
PACS 14.80.Mz; 29.40.Mc; 26.65.+t 相似文献
13.
A. S. Kachan I. V. Kurguz I. S. Kovtunenko V. M. Mischenko V. A. Panin 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(11):1506-1510
The γ decay of the resonance-like structure observed in the 30Si(pγ)31P reaction in the energy range E
p = 1.4–2.7 MeV of accelerated protons has been investigated. The excitation function of this reaction and the spectra and
angular distributions of the γ rays formed in the decay of resonances with E
p = 1482, 2350, and 2505 keV have been measured. The M1 resonance on the ground and the first excited states of 31P with E
p = 1266 keV is identified. The total strength of the M1 resonance on the ground state of this nucleus is determined. The position and total strength of this resonance on the ground
state are explained taking into account pairing forces. 相似文献
14.
S. Ohya T. Ohtsubo T. Izumikawa K. Nishimura S. Muto T. Shinozuka 《Hyperfine Interactions》2007,180(1-3):55-60
Nuclear magnetic resonance on oriented nuclei (NMR-ON) on Sc isotopes (A = 44, 44 m, 46, 47) in Fe were performed. Using the known magnetic moments the magnetic hyperfine fields were determined. The hyperfine anomalies of various Sc were deduced; 44Δ47 = 0.0 (12) %, 44mΔ47 = 1.2 (4) %, 46Δ47 = 2.7 (8) %. The measured hyperfine anomalies are briefly discussed based on the shell model. 相似文献
15.
γ-Ray yield function has been studied for the proton capture by vanadium in the proton energy range 720–1300 keV. Isobaric
analogues of low lying states in52V have been identified. At two resonances theγ-decay andγ-ray angular distributions have been obtained and the branching ratios and the multipole mixing ratios have been deduced.
The analogue-antianalogue M1 transition in52Cr is found to be strongly hindered as in other f7/2 nuclei. TheQ-value obtained for this reaction is (10500±2.8) keV and the Coulomb displacement energy is (8.06±0.01) MeV. An upper limit
of 2 meV has been obtained for theα- decay strength of the 11.395 MeV state in52Cr. 相似文献
16.
The isomeric ratios of the 197m,g
Pt and 197m,g
Hg yields in the respective (γ, n) reactions are measured for the first time in the energy range 8–17 MeV. The isomeric ratios σ
m/σg for 197m,g
Hg in the (d, 2n) reaction are measured in the energy range 8–50 MeV. The experimental data are compared with the results of theoretical calculations.
The effect of the structure of low-lying states and of the yrast line on the behavior of σ
m/σg is revealed.
__________
Translated from Yadernaya Fizika, Vol. 67, No. 5, 2004, pp. 899–905.
Original Russian Text Copyright ? 2004 by Zheltonozhsky, Mazur, Bigan. 相似文献
17.
Abdelmoula M. Petitjean M. Caboche G. Génin J.-M. Dufour L. C. 《Hyperfine Interactions》2004,158(1-4):299-303
TDPAC has been employed to study the local structure of implanted palladium in silicon utilizing 87–75 keV γ–γ cascade of
probe nucleus 100Pd. The observed hyperfine parameters revealed the presence of Pd–V defect pair only in highly doped n-type silicon. A dumbbell
structure with substitutional palladium and silicon vacancy as nearest neigbor is suggested for this defect. 相似文献
18.
Phalet T. Prandolini M.J. Brewer W.D. Dekoster J. De Moor P. Severijns N. Schuurmans P. Turrell B.G. Van Geert A. Vanneste L. Vereecke B. Versyck S. 《Hyperfine Interactions》1999,120(1-8):209-214
Near perpendicular magnetic hyperfine fields in 110mAg have been observed in Fe/Ag multilayers. These fields are studied by low temperature nuclear orientation (LTNO) in multilayers
[Ag(x ML)/Fe(y ML)]20, with (x,y) monolayer (ML) values of (2,10), (3,9), (5,10) and (3,18). The 110mAg γ-ray anisotropy was measured as a function of applied magnetic field parallel to the multilayer. The average induced hyperfine
field of Ag is significantly influenced by the quality of the multilayer as measured by X-ray diffraction.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
M. Forker J. C. Soares K. Krien F. Reuschenbach K. Freitag 《Zeitschrift für Physik B Condensed Matter》1978,29(4):313-317
The magnetic hyperfine field at dilute Hg impurities in Gd has been investigated by the conversion electron (e
–)--time differential perturbed angular correlation (TDPAC) technique. The radioactivities197m
Hg and199Tl were implanted into Gd foils by means of an isotope separator. TDPAC measurements were performed with the 165 keV-L-conversion electron—134 keV--cascade of197Hg at different temperatures and with the 334 keV--158 keV-K-conversion electron cascade of199Hg at 200 K.The regular site occupation probabilities were found to be 15(3)% for an annealed197m
HgGd sample and 29(5)% in unannealed199TlGd samples.From the magnetic hyperfine interaction frequencies measured for the regular sites at 200 K the magnetic hyperfine fields |H
hf(197HgGd; 200 K)|=256(13) kG and |H
hf(199HgGd; 200 K)|=267(7) kG were deduced.On leave from the University of Lisboa, Portugal 相似文献
20.
The 77.3 keV Mössbauer transition of197Au was used to study the hyperfine interactions and recoilfree fractions of dilute Au impurities in Zn and Cd single crystals at 4 K. Mössbauer sources were prepared by ion implantation of197mHg/197Hg at ambient temperature. From the quadrupole splittings the electric field gradients $$\begin{gathered} eq(Au\underline {Cd} ) = + 11.7(6) \times 10^{17} v/cm^2 and \hfill \\ eq(Au\underline {Zn} ) = ( + )15.0(2.5) \times 10^{17} v/cm \hfill \\ \end{gathered} $$ were determined. The electric field gradients as well as the isomer shifts are in good agreement with the systematics of other impurity host systems. The recoilfree fractions agree with estimates using the mass corrected Debye temperatures of the host lattice. 相似文献