共查询到20条相似文献,搜索用时 31 毫秒
1.
L. K. Kostov W. Andrejtscheff L. G. Kostova A. Dewald K. O. Zell P. von Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):179-184
The lifetimes of several negative-parity states in126,130Xe and132Ba have been determined by means of the generalized centroid-shift method. The reactions124,128Te(α,2n) and122Sn(13C, 3n) have been used. Following results were obtained:T 1/2(2758 keV)=1.3±0.2 ns in126Xe,T 1/2(2060 keV)=0.20±0.10 ns,T 1/2(2104 keV)=0.50±0.10 ns,T 1/2(2376 keV)=0.30±0.10 ns andT 1/2(2973 keV)=4.6±0.4 ns in130Xe as well asT 1/2(2120 keV)=0.40 ?0.10 +0.20 ns in132Ba. A systematics of the B(E2; 7 ? 1 ?5 1 ? ) values in theN=76 nuclei is presented. Electric dipole and quadrupole transition rates are discussed in terms of octupole and quadrupole collectivity. The structure of the 5 1 ? and 7 1 ? states is considered. Nuclear reactions:124,128Te(α, 2 n ),E=26 MeV,122Sn (13C, 3n),E=53 MeV; measuredE γ I γ , γ-r.f. DeducedT 1/2, B(σL) in126,130Xe and132Ba. Ge detectors. Generalized centroid-shift analysis. 相似文献
2.
The half lives of the excited levels at 482.2 keV and 615.3 keV in181Ta have been measured by the delayed coincidence technique. In the nanosecond time range (482.2 keV level) the most serious sources of errors are jitter, walk and drift phenomena. To minimize those the time pick-off has been defined carefully by means of modern fast timing detectors and electronics. In the microsecond time range (615.3 keV level) the ratio of true delayed coincidences to chance coincidences influences considerably the final accuracy of the half-life measurements. It has been reduced as much as possible. From a series of independent measurements half lives ofT 1/2=(10.67±0.05) ns andT 1/2=(17.64±0.14) μs have been deduced for the 482.2 keV and 615.3 keV levels, respectively. The results have been compared with other values published before. 相似文献
3.
Y. Nagai J. Styczen M. Piiparinen P. Kleinheinz 《Zeitschrift für Physik A Hadrons and Nuclei》1980,296(1):91-92
A 53.3 keV E2 transition de-exciting the 60 ns isomer in152Dy has been identified in γγ-coincidence measurements, which locates that isomer at Ex=5088 keV. The half life of the 11? level at 3161 keV was measured to be T1/2=4.3±0.9 ns. 相似文献
4.
A. Nylandsted Larsen D. Mouchel H. H. Hansen 《Zeitschrift für Physik A Hadrons and Nuclei》1980,294(2):191-195
Measurements of the half-life of the 23.87 keV level in119Sn have been performed by delayed coincidence technique. Two different types of sources have been used in experiments with various detector combinations. A very pure source was made by implanting119m Sn in a plastic scintillator by an isotope separator. This source could simultaneously be used as source and detector. The other source was made by simple drying of a drop of solution. The mean value of the half-life of the 23.87 keV level from 21 measurements is found to beT 1/2=(18.03±0.07) ns. 相似文献
5.
J. Glatz 《Zeitschrift für Physik A Hadrons and Nuclei》1973,265(4):335-364
Prompt and delayedγ-γ-coincidences were measured after slow neutron capture in185Re by use of Ge(Li)-detectors. New isomers were found at 99.4 keV (T1/2=27±7ns) and at ≈330keV (T1/2=17.4±0.7 ns). The evaluation of coincidence data established 10 rotational bands with band heads below 700 keV. The level scheme is discussed in detail: Nilsson assignments are proposed for the band configurations, and calculations of Coriolis mixing andγ-transition probabilities are presented which reproduce the experimental level energies and transition intensities very satisfactorily. 相似文献
6.
K. E. G. Löbner 《Zeitschrift für Physik A Hadrons and Nuclei》1968,216(4):372-397
The half-lives of the following intrinsic states in deformed odd-mass nuclei has been measured by delayed coincidences with a time-to-amplitude converter:
- 5/2 5/2+[642] at 86.5 keV in155Gd:T 1/2=6.7±0.3 ns, which results in the determination of theE1,ΔK=1 transition probability to the ground state 3/2 3/2?[521] and first rotational state 5/2 3/2?[521], yielding hindrance factors ofF N ≈5.5 and ≈1.8 (F W =3.1×104 and 2.3×104) respectively.
- (3) 5/2 5/2?[512] at 191.4 keV in169Yb:T 1/2=3.35±0.15 ns and at 122.39 keV in171Yb:T 1/2=265±20 ns which results in the determination of the transition probabilities of theE1,ΔK=1 transitions to the ground states 7/2 7/2+[633], of theK-forbiddenM1 transitions to the 5/2 and 3/2 1/2?[521] and of theE2 transitions to the 5/2, 3/2 and 1/2 1/2?[521] states in both nuclei.
7.
N. P. S. Sidhu T. S. Cheema T. Iwashita H. S. Sahota 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(1):45-50
Bombarding a85Rb target by 27 MeVα-particles the following half-lives of excited states in different nuclei have been determined by means of the generalized controid shift method: in87Y,T 1/2(2827.1 keV)=0.75±0.10 ns,T 1/2(2675.9 keV)=0.25±0.10 ns,T 1/2(3595.3 keV)=0.5±0.2 ns andT 1/2(2986.9, 3094.4 keV)<0.1 ns; in88Y,T 1/2(232.1 keV)=0.8±0.1 ns and in85Rb,T 1/2(151.2 keV)=0.6±0.1 ns. In87Y, the members of the doublet (vg 9 2/?2 )8+ (πp1/2) are identified. E2 transition rates 21/2+? 17/2+ in odd A≈ 90 nuclei are shown to represent essentially core transitions. Evidence for the existence of seniority-five configurations is found. 相似文献
8.
I. Penev W. Andrejtscheff Ch. Protochristow Zh. Zhelev 《Zeitschrift für Physik A Hadrons and Nuclei》1984,318(2):213-217
The half-life of the 53.2 keV level in214Bi has been measured asT 1/2=0.52±0.15 ns, furtherT 1/2(295.2 keV and 351.9 keV levels)≦0.10 ns was estimated. TheB(M1,2?→1?) transition rates within theπh 9/2 vg 9/2 multiplet in210,212,214Bi are found to decrease rapidly with increasing neutron number, reaching in214Bi a value as low as those typical for intraband M1 transitions in deformed odd-odd nuclei. 相似文献
9.
L. K. Kostov W. Andrejtscheff L. G. Kostova A. Dewald K. O. Zell P. von Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1974,355(2):179-184
The lifetimes of several negative-parity states in 126,130Xe and 132Ba have been determined by means of the generalized centroid-shift method. The reactions 124,128Te(α, 2n) and 122Sn(13C, 3n) have been used. Following results were obtained: T1/2(2758 keV) = 1.3 ± 0.2 ns in 126Xe, T1/2 (2060 keV) = 0.20 ± 0.10 ns, T1/2 (2104 keV) = 0.50 ± 0.10 ns, T1/2 (2376 keV) = 0.30 ± 0.10 ns and T1/2 (2973 keV) = 4.6 ± 0.4 ns in 130Xe as well as T 1/2(2120 keV) = 0.40 ?0.10 +0.20 ns in 132Ba. A systematics of the B(E2; 7 1 ? ? 5 1 ? ) values in the N = 76 nuclei is presented. Electric dipole and quadrupole transition rates are discussed in terms of octupole and quadrupole collectivity. The structure of the 5 1 ? and 7 1 ? states is considered. Nuclear reactions: 124,128Te(α, 2n), E = 26 MeV, 122Sn (13C, 3n), E = 53 MeV; measured E{gg}, I{gg}, γ-r.f. Deduced T1/2, B(σL) in 126,130Xe and 132Ba. Ge detectors. Generalized centroid-shift analysis. 相似文献
10.
S. Antman H. Pettersson Z. Zehlev I. Adam 《Zeitschrift für Physik A Hadrons and Nuclei》1970,237(4):285-291
The internal conversion subshell intensities of the (21.529±0.014) keV transition in151Eu and the (22.494±0.011) keV transition in149Sm have been determined in a high resolution investigation using a double-focussing iron-core spectrometer. The subshell ratios yielded unambiguousM1+E2 multipole mixtures for both transitions. δ2(E2/M1) for the 21.53 keV transition was determined to be (8.8±0.7)·10?4 and for the 22.49 keV transition to be (5.5±1.2)·10?3. 相似文献
11.
Using theγ-radiation of 748 and 28 keV the half-lives of the first two excited states in51Cr at 748 and 776 keV have been measured by a pulsed beam technique. The interesting states were populated by the reaction51V(p, nγ)51Cr at 4 MeV proton energy. The half-lives were found to beT 1/2(51Cr, 748 keV)=(7.35±0.03) ns andT 1/2(51Cr, 776 keV)=(5.53±0.07) ns. The influence of the 28 keV transition between the two levels upon the lifetime of the 748 keV state has been investigated. The 776 keV-state populates the 748 keV state only by 8.4%. The lifetime of the 776 keV state, therefore, cannot account for the anomalous long lifetime of the level at 748 keV as has been proposed by Bartholomew et al. 相似文献
12.
A. Visvanathan E. G. Funk J. W. Mihelich 《Zeitschrift für Physik A Hadrons and Nuclei》1974,271(4):339-343
TheK-internal conversion coefficients have been measured by the XPG technique for a number of low energyγ-ray transitions whose energies do not exceed theK-binding energies by more than 4 keV. Using Si(Li) detectors in singles and coincidence arrangements, the following results were obtained: 63.1 keV El in169Tm(αK=1.02±0.15), 72.0 keV E1 in187Re (0.75±0.05), 57.8 keV M1 in162Ho (11.42±0.67), 56.6 keV M1 in164Ho (12.04±0.70), and 67.1 keV M1 in174Lu(10.25±0.58). The experimental results are compared with the theoretical calculations which include transition energies down to 1 keV above threshold. 相似文献
13.
H. de Waard E. N. Kaufmann J. W. Rodgers 《Zeitschrift für Physik A Hadrons and Nuclei》1973,264(5):423-426
A valueg=0.38±0.06 was obtained for theg-factor of the 668 keV state of132Xe (τ=7.3±0.6 psec) from time-integral perturbed angular correlation measurements on gamma cascades in132Xe. Sources of132Te implanted in iron were used to obtain a magnetic hyperfine field of 1510±100 kG at the132Xe nuclei. 相似文献
14.
R. K. Garg S. D. Chauhan Suvra Sanyal S. C. Pancholi S. L. Gupta N. K. Saha 《Zeitschrift für Physik A Hadrons and Nuclei》1972,257(2):124-136
The half-lives of the 1291.6 keV level in59Co, 145.43 keV level in141Pr and 27.35 keV level in227Ac have been measured using leading edge and zero-crossover timing techniques. The decay curves analysed by moments, Laplace transform and slope methods gave the following half-life values: $$\begin{gathered} T_{\tfrac{1}{2}} (1291.6 keV level in {}^{59}Co) = (0.538 \pm 0.004) ns \hfill \\ T_{\tfrac{1}{2}} (145.43 keV level in {}^{141}\Pr ) = (1.82 \pm 0.04) ns \hfill \\ T_{\tfrac{1}{2}} (27.35 keV level in {}^{227}Ac) = (41.0 \pm 1.1) ns. \hfill \\ \end{gathered} $$ From the measured half-lives, the reduced transition probabilitiesB(M1)↓,B(E2)↓ for gamma transitions de-exciting the above mentioned levels in59Co and141Pr are determined and compared with single particle, intermediate coupling and Sorensen estimates. In227Ac, absolute transition probability for the 27.35 keV transition is determined and compared with single particle and Nilsson estimates. 相似文献
15.
Lifetime measurements of two excited states in131Xe populated by the decay of131I have been carried out. Analysis of data, delivered from a delayed γ-γ-coincidence experiment with a Ge(Li)-Plasticdetector combination, resulted in the following values:T 1/2 of 341.2 keV level in131Xe: (2.15 ± 0.07) nsT 1/2 of 404.8 keV level in131Xe: <0.5 ns. 相似文献
16.
L. K. Kostov W. Andrejtscheff L. G. Kostova A. Dewald G. Böhm K. O. Zell P. von Brentano H. Prade J. Döring R. Schwengner 《Zeitschrift für Physik A Hadrons and Nuclei》1990,337(4):407-412
By means of the generalized centroid-shift method, the following half-lives were determined:T 1/2(3045 keV)=3.7±0.3 ns in113Sb using the reaction104Pd(12C,p2n) as well asT 1/2 (1322.8 keV)=3.5±0.3 ns,T 1/2(2779.8 keV) =0.50±0.15ns,T 1/2(2874.9 keV)<0.2 ns andT 1/2(3072.9 keV)<0.1 ns in117Sb using the116In(α, 2n) reaction. Three-quasiparticle configurations of the type πd 5/2ν(h11/2 d 3/2) in113,117Sb are found to dominate in the wave functions of the 19/2? states at 3045 and 2780 keV in113Sb and117Sb, respectively. TheB(E2, 19/2? → 15/2?) values in113–119Sb are discussed. 相似文献
17.
A. Nowak W. Urban W. Kurcewicz T. Rząca-Urban H. Mach B. Fogelberg J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley M. Bentaleb E. Lubkiewicz N. Schulz I. Ahmad L.R. Morss 《The European Physical Journal A - Hadrons and Nuclei》1999,4(1):1-3
132Te was produced via the 232Th (α, fission) reaction at the Variable Energy Cyclotron , Calcutta. 132Te was separated in carrier-free form from the fission products by radiochemical separation and the half-lives for the 50
keV and 162 keV states of 132I were determined to be 2.94±0.11 ns and 0.55±0.04 ns respectively. The present results differ significantly from the previously
reported half-lives of 7.14 ns and 3.57 ns for the 50 keV and 162 keV states respectively.
Received: 28 July 1998 / Revised version: 23 September 1998 相似文献
18.
R. Alfier D. Alber H. Grawe H. Kluge K. H. Maier R. Schubart D. B. Fossan W. F. Piel Jr. 《Zeitschrift für Physik A Hadrons and Nuclei》1974,267(2):135-143
Conversion coefficients and conversion ratios of someγ-transitions in201Tl and203Tl were measured by means of simultaneous spectroscopy ofγ-quanta and conversion electrons employing intensity calibrated semiconductor detectors. The experiments aimed at a precision as high as possible within the limits of the experimental methode used. Theγ-transitions were of the typeM 1(+E2). From the measured values the penetration parameters of the internal conversion for theM 1 components (λ) together with the multipol mixing ratios (δ2) were deduced. The necessary theoretical coefficients were taken from the tables of Hager and Seltzer. The results are for the ?-forbidden 331 keV transition in201Tl,λ=+4.0±1.0,δ 2=1.78±0.16; for the ?-allowed 361 keV transition in201Tl,λ=+0.5±0.5,δ 2=0.02±0.02; for the ?-forbidden 279 keV transition in203Tl,λ=+ 5.71±0.45,δ 2=1.55±0.08. 相似文献
19.
Jean Kern J. B. Carlson R. G. Lanier L. G. Mann G. L. Struble 《Zeitschrift für Physik A Hadrons and Nuclei》1980,296(3):195-200
Levels in174Lu have been investigated using the176Yb(p,3n) reaction. Prompt and delayedγ-ray spectra have been observed with a 0.56-cm3 Ge(Li) detector by a multispectrum analysis method. The half-life and decay mode of two isomeric levels, one at 240.8keV (395±15ns) and the other at 365.1keV (145±3ns) have been firmly established. Hindrance factors are discussed. New delayed transitions in175Lu are also noted. 相似文献
20.
H. A. Selič G. Sadler T. A. Khan W. -D. Lauppe H. Lawin K. Sistemich E. Monnand J. Blachot J. P. Bocquet F. Schussler 《Zeitschrift für Physik A Hadrons and Nuclei》1979,289(2):197-210
Theβ-decays of99Y and99Zr have been investigated with the two recoil fission product separators JOSEF and LOHENGRIN. Half-lives of 1.51±0.08s and 2.1±0.1s respectively, have been determined. Aβ-decaying isomeric state has been observed in99Y. The level schemes of 40 99 Zr59 and 41 99 Nb58 have been established fromγ-ray spectroscopy. Absoluteγ-intensities have been obtained by means of two independent techniques. Halflives of 293±10 ns for the 251.9 keV state and 10.2±1.5 ns for the 614.0 or 667.2 keV level in99Zr have been measured through delayedβ,γ- andγ,γ-coincidence experiments. Values for the spins and parities of the low lying levels in99Zr are proposed in accordance with the systematics of lighter odd Zr isotopes. Spins and partities are assigned to some levels in99Nb fromγ,γ-angular correlation measurements. In this nucleus there is evidence for three-particle configurations of some excited states, where the odd proton is coupled to two neutrons which are in different orbits. 相似文献