共查询到20条相似文献,搜索用时 390 毫秒
1.
M. Ertuğrul E. Büyükkasap A. Küçükönder A. İ. Kopya H. Erdoğan 《Il Nuovo Cimento D》1995,17(9):993-998
Summary The anisotropy of emission intensity ofL-shell X-rays induced by 59.5 keV photons in Au and Hg was investigated at different angles varying from 45° to 135°. It is
observed thatLl andLα X-rays (originating fromJ=3/2) are anisotropic,Lβ andLγ X-rays (originating fromJ=1/2, commonly) are isotropic. 相似文献
2.
The angular dependence of emission intensity of L shell X-rays induced by 59.57 keV photons in Pb and U is investigated by
measuring the normalized intensities of the resolved L X-ray peaks at different angles varying from 40° to 120°. It is observed
that while L
l
and Lα X-ray peaks (originating fromJ = 3/2 state) show some anisotropic angular distribution, the emission of Lβ and Lγ X-ray peaks is isotropic. The present results contradict the calculations of Co-oper and Zare (1969) that after photoionization
of inner shell, the vacancy state has equal population of magnetic substates and the subsequent X-ray emission is isotropic
but confirm the predictions of Fluggeet al (1972) that the atomic inner shell vacancies produced after photoionization are aligned and the x-ray emission from the filling
of vacancies in state withJ ⩾ 3/2 is anisotropic. 相似文献
3.
D. Demir Y. Şahin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):211-216
The effect of external magnetic field on the Kα
and Kβ X-ray production cross-sections and K shell fluorescence
yields for ferromagnetic elements Nd, Gd and Dy and paramagnetic elements Eu
and Ho have been measured at the excitation energy of 59.5 keV γ
-rays from 241Am radioactive source of strength 100 mCi in the
external magnetic field of intensities ±0.75 T. Furthermore,
IKβ /IKα intensity ratios for these elements have been
measured in the external magnetic field. The K X-rays from different targets
were detected using a high resolution Si(Li) semiconductor detector. For B = 0, the measured K X-ray production cross-sections,
K shell fluorescence
yields and the IKβ /IKα intensity ratios were compared
with the experimental and theoretical data in literature. The results have
shown that the fluorescence parameters as photoionization cross section,
fluorescence yield, radiation rates and spectral linewidth can change when
the irradiation is conducted in a magnetic field. 相似文献
4.
In an effort to resolve the existing discrepancy between experiment and theory, the cross-sections for the production ofL
l,L
α
,L
β
andL
γ
groups ofL-shell X-rays of Ho by photons of nine energies in the range 10–40 keV have been measured using an improved version of annular
source double reflection geometrical set-up. Contrary to the earlier findings of Garget al that the measured values of the cross-sections are consistently higher than those calculated theoretically, the present results
do not confirm this. The plausible deficiencies in the experiments of Garget al are pointed out and possible remedies to overcome them are suggested. It is concluded that the higher values obtained by
Garget al are probably due to systematic errors in their method of measurement. 相似文献
5.
H.Y. Wang Z.W. Ma E.Y. Jiang Y.J. He H.S. Huang 《Applied Physics A: Materials Science & Processing》1999,68(5):559-562
The structure and magnetic properties of Fe-N and Fe-Ti-N films have been studied as a function of annealing temperature Ta with a transmission electron microscope and a vibrating sample magnetometer. The as-prepared Fe-N films consist of the γ′-Fe4N and α′′-Fe16N2 phases, and the Fe-Ti-N films are composed of the γ′-Fe4N, α′′-Fe16N2, and TiN phases. The structural changes with annealing temperature in the Fe-N films are distinct. The α′′-Fe16N2 decomposes into α+γ′ phases in the Fe-N film annealed at about 300 °C, and it disappears in the film annealed at 350 °C. Annealing of the Fe-Ti-N
films shows no structural changes between room temperature (RT) and 500 °C. The saturation magnetization 4πMS and coercivity Hc of the Fe-N films change drastically with the annealing temperature Ta, whereas those of the Fe-Ti-N films do not change with Ta up to 500 °C. These results indicate that the additon of Ti may improve the thermal stability of Fe-N films.
Recieved: 6 Juli 1998 / Accepted: 19 Oktober 1998 / Published online: 10 March 1999 相似文献
6.
The local susceptibility, below and above the γ-α transition, was measured with the DPAC method using the140Ce probe. The ratio β between the local and the applied field was βγ=1.20(2) and βα=1.13(1) at 295 K. The latter value is larger than expected for a completely delocalized 4f electron. 相似文献
7.
Y Ramakrishna K Ramachandra Rao G J Naga Raju K Bhaskara Rao V Seshagiri Rao P Venkateswarlu S Bhuloka Reddy 《Pramana》2002,59(4):685-691
The energy shifts and intensity ratios of different L X-ray components in tantalum element due to 10 MeV carbon and 12 MeV
nitrogen ions are estimated. From the observed energy shifts, the possible number of simultaneous vacancies in M shell are
estimated. A comparison of L
α
/L
β2.15, L
β1/L
γ1 and L
γ2.3/L
γ4.4 with the ratios due to Scofield theoretical transition rates indicate that the number of multiple vacancies in N shell are
higher than the vacancies in M and O shell. Employing Larkin’s statistical scaling procedure, the number of possible multiple
vacancies in N and O shells are estimated quantitatively. 相似文献
8.
We present an estimate of the cross-section for the exclusive production of a ρL
0-meson pair in e+e- scattering, which will be studied in the future high-energy International Linear Collider. For this aim, we complete calculations
of the Born order approximation of the amplitudes γ*
L,T(Q1
2)γ*
L,T(Q2
2)→ρL
0ρL
0, for arbitrary polarization of virtual photons and longitudinally polarized mesons, in the kinematical region s≫-t,Q1
2,Q2
2. These processes are completely calculable in the hard region Q1
2,Q2
2≫Λ2
QCD, and we perform most of the calculations in an analytical way. The resulting cross-section turns out to be large enough for
this process to be measurable with foreseen luminosity and energy, for Q1
2 and Q2
2 in the range of a few GeV2. 相似文献
9.
Indranil Chakrabarty Sovik Roy Nirman Ganguly Binayak S. Choudhury 《International Journal of Theoretical Physics》2009,48(6):1833-1840
In this work we describe a protocol by which two of three parties generate two bipartite entangled state among themselves
without involving third party, from a non maximal W-state or W-type state |X〉=α|001〉123+β|010〉123+γ|100〉123,α
2+β
2+γ
2=1 shared by three distant partners. Also we have considered the case β=γ, to obtain a range for α
2, for which the local output states are separable and non local output states are inseparable. We also find out the dependence
of the mixedness of inseparable states with their amount of inseparability, for that range of α
2. 相似文献
10.
Chemical effects on the Kβ/Kα X-ray intensity ratios
for some Mn, Ni, and Cu complexes of a new schiff-base with salen
N2H2 type were investigated. The samples were excited by 59.543
keV γ-rays from a 241Am annular radioactive source. K X-rays
emitted by samples were counted by a Si(Li) detector with resolution 157 eV
at 5.9 keV. We observed the chemical effect on the Kβ/Kα
X-ray intensity ratios for Mn, Ni and Cu complexes. The experimental
results showed that the Kβ/Kα X-ray intensity ratios
for compounds with complexes are generally larger than those with salt form.
The experimental values have been compared with the other experimental and
the theoretically calculated values of pure elements. The results are in
very good agreement with the others. 相似文献
11.
High resolution gamma-ray spectra have been measured from the27Al (p,γ)28Si reaction for the resonances atE
p=2·482, 2·511 and 2·735 MeV at ϑ
pγ=0°, 30°, 55° and 90° using a Ge (Li) gamma spectrometer. From the spectra and the angular distributions the properties of
the resonance states have been obtained. These states are the isobaric analogues of the levels at 4·69, 4·75 and 4·93MeV levels
respectively in the parent nucleus A28l. 相似文献
12.
A complex study of the hydrogen reduction of nanosized iron hydroxide Fe(OH)3 at 400°C was performed. It was shown that, during the reduction of Fe(OH)3 to iron metal α-Fe, intermediate compounds such as Fe(OH)2, α-FeOOH, β-FeOOH, γ-FeOOH, δ-FeOOH, and FeO are formed along with stable iron oxides α-Fe2O3, γ-Fe2O3, and Fe3O4. A scheme of chemical and structural transformations that occur in the reduction of nanosized Fe(OH)3 is presented. The scheme takes into account the possibility of the bifurcation mechanism of reaction development. 相似文献
13.
K. Kossert M. Camen F. Wissmann J. Ahrens J.R.M. Annand H.-J. Arends R. Beck G. Caselotti P. Grabmayr O. Jahn P. Jennewein M.I. Levchuk A.I. L'vov J.C. McGeorge A. Natter V. Olmos de León V.A. Petrun'kin G. Rosner M. Schumacher B. Seitz F. Smend A. Thomas W. Weihofen F. Zapadtka 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):259-273
Differential cross-sections for quasi-free Compton scattering from the proton and neutron bound in the deuteron have been
measured using the Glasgow/Mainz photon tagging spectrometer at the Mainz MAMI accelerator together with the Mainz [48]cm
;SPMOslash; × [64]cm NaI(Tl) photon detector and the G?ttingen SENECA recoil detector. The data cover photon energies ranging from [200]MeV
to [400]MeV at θLAB
γ = 136.2°. Liquid deuterium and hydrogen targets allowed direct comparison of free and quasi-free scattering from the proton. The neutron
detection efficiency of the SENECA detector was measured via the reaction p(γ,π+
n). The “free” proton Compton scattering cross-sections extracted from the bound proton data are in reasonable agreement with
those for the free proton which gives confidence in the method to extract the differential cross-section for free scattering
from quasi-free data. Differential cross-sections on the free neutron have been extracted and the difference of the electromagnetic
polarizabilities of the neutron has been determined to be αn - βn = 9.8±3.6(stat)+2.1
-1.1(syst)±2.2(model) in units of [10-4]fm
3. In combination with the polarizability sum αn + βn = 15.2±0.5 deduced from photoabsorption data, the neutron electric and magnetic polarizabilities, αn = 12.5±1.8(stat)+1.1
-0.6(syst)±1.1(model) and βn = 2.7±1.8(stat)+0.6
-1.1(syst)±1.1(model) are obtained. The backward spin polarizability of the neutron was determined to be γ(n)
π = (58.6±4.0)×10-4
fm
4.
Received: 21 August 2002 / Accepted: 16 October 2002 / Published online: 11 February 2003
RID="a"
ID="a"Part of the Doctoral Thesis.
RID="b"
ID="b"Present address: Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig.
RID="a"
ID="a"Part of the Doctoral Thesis.
RID="b"
ID="b"Present address: Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig.
RID="c"
ID="c"Part of the Habilitation Thesis.
RID="d"
ID="d"e-mail: schumacher@physik2.uni-goettingen.de
Communicated by Th. Walcher 相似文献
14.
Electrochemical preparation of nanosized manganese dioxides from manganese chloride solutions 总被引:1,自引:0,他引:1
Manganese dioxides were fabricated by electrodeposition from MnCl2, MgCl2/MnCl2, and HCl/MnCl2 aqueous solutions at 100 °C, respectively. Oxidation behaviors of Mn(II) on titanium plate were studied by cyclic voltammetry.
X-ray diffractometer, scanning electron microscopy, and BET measurements were used to characterize manganese dioxide crystal
structures, micromorphologies, and specific surface area. The effects of electrolyte composition and potential on manganese
dioxide crystal structure and micromorphology were investigated. Manganese dioxide structure type and micromorphology were
controlled by adjusting electrolyte composition. γ-MnO2 aggregates consisting of nanosheets were electrodeposited from 0.05 mol L−1 MnCl2 aqueous solution. Crystallinity and the size of γ-MnO2 nanosheet were increased by adding Mg(II) into electrolyte. Nanosized rod-like α-MnO2 with higher specific surface area was prepared by adding 2.0 mol L−1 hydrochloric acid into manganese chloride solution. 相似文献
15.
B. Ertuğral G. Apaydın A. Tekbıyık E. Tıraşoğlu U. Çevik A. İ. Kobya M. Ertuğrul 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,37(3):371-375
K to L shell vacancy transfer probabilities (ηKL) for
26 elements in the atomic region 23≤Z≤57 were determined by measuring
the IKβ/IKα intensity ratios. The targets were irradiated
with γ-photons at 59.543 keV from 241Am annular source. The K
X-rays from different targets were detected with a high resolution Si(Li)
detector. Theoretical values were calculated using the radiative and
radiationless transition rates of these elements. The measured values of
ηKL are compared with the theoretical values and data of others. The
measurement vacancy transfer probabilities are least-square fitted to
third-order polynomials to obtain analytical relations that represent these
probabilities as a function of atomic number. The measured values of ηKL
for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se and Br are being reported here for
the first time. 相似文献
16.
J. Kurpeta A. Andreyev J. Äystö A.-H. Evensen M. Huhta M. Huyse A. Jokinen M. Karny E. Kugler J. Lettry A. Nieminen A. Płochocki M. Ramdhane H.L. Ravn K. Rykaczewski J. Szerypo P. Van Duppen G. Walter A. Wöhr 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):49-54
The decay of the neutron–rich isotope 216Bi, produced by proton–induced spallation at the PS Booster–ISOLDE facility, was investigated by β-γγ, αγ coincidence and
spectrum-multiscaling measurements. A new method for reducing isobaric contamination enabled to cover the unknown region “east”
of 208Pb for the isobaric chain A=216. The half-life of the β decay of 216Bi was found as T1/2= 135 ± 5 s. Its decay scheme was extended and the possible shell model configurations are proposed.
Received: 13 July 1999 / Revised version: 22 September 1999 相似文献
17.
N. L. Achouri F. de Oliveira Santos M. Lewitowicz B. Blank J. Äystö G. Canchel S. Czajkowski P. Dendooven A. Emsallem J. Giovinazzo N. Guillet A. Jokinen A. M. Laird C. Longour K. Peräjärvi N. Smirnova M. Stanoiu J. -C. Thomas 《The European Physical Journal A - Hadrons and Nuclei》2006,27(3):287-300
In an experiment performed at the LISE3 facility of GANIL, we studied the decay of 22Al produced by the fragmentation of a 36Ar primary beam. A β-decay half-life of T1/2 = 91.1±0.5ms was measured. The β-delayed one- and two-proton emission as well as β-α and β-delayed γ-decays were measured
and allowed us to establish a partial decay scheme for this nucleus. New levels were determined in the daughter nucleus 22Mg. The comparison with model calculations strongly favours a spin-parity of Iπ = 4+ for the ground state of 22Al. 相似文献
18.
M. Schumacher 《The European Physical Journal A - Hadrons and Nuclei》2007,34(3):293-301
The signs and values of the two-photon couplings F
Mγγ of mesons (M) and their couplings gMNN to the nucleon as entering into the t -channel parts of the difference of the electromagnetic polarizabilities (α - β) and the backward angle spin polarizabilities
γπ are determined. The excellent agreement achieved with the experimental polarizabilities of the proton makes it possible to
make reliable predictions for the neutron. The results obtained are αn = 13.4±1.0 , βn = 1.8±1.0 (10-4fm^3), and γ(n)
π = 57.6±1.8 (10-4fm^4). New empirical information on the flavor wave functions of the f
0(980) - and the a
0(980) -meson is obtained. 相似文献
19.
K. K. Abdullah K. Karunakaran Nair N. Ramachandran K. M. Varier B. R. S. Babu Antony Joseph Rajive Thomas P. Magudapathy K. G. M. Nair 《Pramana》2010,75(3):459-469
Mass attenuation coefficients (μ/ρ) for Zr, Nb, Mo and Pd elements around their K-edges are measured at 14 energies in the range 15.744–28.564 keV using secondary excitation from thin Zr, Nb, Mo, Rh, Pd,
Cd and Sn foils. The measurements were carried out at the K
α
and K
β
energy values of the target elements by two techniques: (1) Proton-induced X-ray emission (PIXE) and (2) 241Am (300 mCi) source. In PIXE, 2 MeV proton-excited X-rays were detected by a Si(Li) detector. In the second case, X-rays excited
by 59.54 keV photons from the targets were counted by an HPGe detector under a narrow beam good geometry set-up with sufficient
shielding. The results are consistent with theoretical values derived from the XCOM package and indicate that the PIXE data
have better statistical accuracy. 相似文献
20.
Ya.I. Azimov 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):209-219
Isospin-violating mixing of ρ- and ω-mesons is reconsidered in terms of propagators. Its influence on various pairs of (ρ,ω)-decays
to the same final states is demonstrated. Some of them, (ρ,ω)↦π+π- and (ρ,ω)↦πγ, have been earlier discussed in the literature, others (e.g., (ρ,ω)↦ηγ and (ρ,ω)↦e
+
e
-) are new in this context. Changes in partial widths for all the decay pairs are shown to be correlated. The set of present
experimental data, though yet inconclusive, provides some limits for the direct (ρω)-coupling and indirectly supports enhancement
of ρ↦πγ in comparison with ρ±↦π±γ, though not so large as in some previous estimates.
Received: 16 September 2002 / Accepted: 23 September 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: azimov@pa1400.spb.edu
Communicated by V.V. Anisovich 相似文献