Subshell Fluorescence Yields Research Articles

M i ( i = 1–5) subshell fluorescence and Coster–Kronig yields for elements with 67 ⩽ Z ⩽ 92

A complete set of the M i ( i = 1–5) subshell fluorescence and Coster–Kronig (CK) yields has been generated by interpolation for elements with 67 ⩽ Z ⩽ 92 from the Dirac–Hartree–Slater (DHS) model based values tabulated for a limited number of elements, considering the cutoff/onset of different CK transitions in accordance with the CK transition energies evaluated in the present work. The CK transition energies have been deduced from tabulated values of the Dirac–Hartree–Fock–Slater model based neutral atom binding energies [K. Huang, M. Aoyagi, M.H. Chen, B. Crasemann, H. Mark, At. Data Nucl. Data Tables 18 (1976) 243] and the L i ( i = 1–3) subshell CK transition energies [M.H. Chen, B. Crasemann, K. Huang, M. Aoyagi, H. Mark, At. Data Nucl. Data Tables 19 (1977) 97] in order to establish the cutoff/onset of different CK transitions at specific atomic numbers. A second set of the M i ( i = 1–5) subshell fluorescence yields have also been deduced using radiative widths computed from the Dirac–Fock (DF) model based X-ray emission rates, and the total widths reevaluated to incorporate the DF model based radiative widths in place of those based on the DHS model. Further, the CK-corrected ( ν i ) and average fluorescence ( ϖ M) fields, which are experimentally important, have been evaluated from the generated set of CK yields and two sets of fluorescence yields.

The effect of an external magnetic field on the L subshell X-ray fluorescence cross sections and L subshell fluorescence yields in elements 73 ≤ Z ≤ 92 by 59.54 keV photons

L i ( i = 1, 2 and 3) X-ray fluorescence cross sections for Ta, W, Au, Hg, Tl, Pb, Bi, Th and U have been measured using the 59.54 keV incident photons energy in the external magnetic field of intensity +0.60 T. The values of L i subshell fluorescence yields ( w 1 , w 2 and w 3 ) have been measured for the same elements using the previously measured cross section values and the theoretical L i subshell photoionisation cross sections, Coster–Kronig transition probabilities and emission rates. It is observed that the measured L i subshell X-ray fluorescence cross section and L i subshell fluorescence yield values for B = 0 are in good agreement with the theoretical ones evaluated using L i subshell fluorescence yield and L i subshell photoionization cross section. Furthermore, the results show that the atomic parameters such as spectral linewidth, radiation rates, photoionization cross section and fluorescence yield can change when the irradiation is conducted in a magnetic field.

The effect of an external magnetic field on the L 3 subshell fluorescence yields and level widths for Ta, W, Tl, Th and U at 59.54 keV photons

The effect of an external magnetic field on the L3 subshell fluorescence yields (ω3 ) and level widths ($\Gamma_{L_3}$) for paramagnetic Ta, W, Tl, Th and U have been investigated using the 59.54 keV incident photon energy in the external magnetic field of intensities ±0.60 T. L3 X-ray fluorescence cross sections ($\sigma_{L_3}^{X}$) have been measured for the same elements. The measured ω 3, $\Gamma_{L_3} $ and $ \sigma_{L_3}^X$ values for B = 0 are in good agreement with the theoretical values. It was observed that the values of $\sigma_{L_3}^X$ and ω3 with the applied magnitude of the magnetic field in both directions show a decreasing trend for paramagnetic Ta, W, Tl, Th and U. Furthermore, in the presence of an external magnetic field, the values of $\Gamma_{L_3}$ show an increasing trend for the same elements. The results show that the atomic parameters such as spectral linewidth, radiation rates, photoionization cross section and fluorescence yield can change when the irradiation is conducted in a magnetic field.

Measurements of L X-ray production cross sections, L subshell fluorescence yields and K to L shell vacancy transfer probabilities

L i X-ray production cross sections have been measured for Sm, Eu, Gd, Dy, Ho, Er, Pt, Au, Tl, Pb and Bi at 59.54 keV incident photon energy. The values of L i subshell fluorescence yields ( ω 1, ω 2 and ω 3) have been determined using the presently measured X-ray production cross sections and the theoretical L i subshell photoionization cross sections values, Coster–Kronig transition probabilities and radiative emission rates. Furthermore, K to L shell vacancy transfer probabilities η KL i ( i=1, 2, 3) for Sm, Eu, Gd, Dy, Ho, Er were determined by measuring the L X-ray production cross section and L subshell fluorescence yields. The measurements were performed using an Am-241 radioisotope as the photon source and a Si(Li) detector. The measured X-ray production cross sections, fluorescence yields and vacancy transfer probabilities were compared with the theoretical values. The results in the present paper are found to be in good agreement with the calculated values.

The effect of an external magnetic field on the L3 subshell fluorescence yields and level widths for Gd, Dy, Hg and Pb at 59.5 keV

The effect of external magnetic field on the L3 subshells fluorescence yields (ω3) and level widths (ΓL3) for ferromagnetic Gd and Dy and diamagnetic Hg and Pb have been investigated using the 59.5keV incident photon energy in the external magnetic field of intensities ±0.75T. L3 X-ray production cross sections (σL3X) have been measured for the same elements. The measured ω3, ΓL3 and σL3X values for B=0 are in good agreement with the theoretical values. It was observed that the values of ω3 and σL3X with the applied magnitude of the magnetic field in both directions increase for ferromagnetic Gd and Dy but decrease for diamagnetic Hg and Pb. Furthermore, in the presence of an external magnetic field, the values for ΓL3decrease for Gd and Dy, and increase for Hg and Pb. The results show that the atomic parameters such as spectral linewidth, radiation rates, photoionization cross section and fluorescence yield can change when the irradiation is conducted in a magnetic field.

Study of vacancy decays in the L-shell photoionization of barium in the excitation energy range of 5.6–30 keV: from L2 edge to energy high above the thresholds of double L-vacancy production

Photoinduced Ba L x-rays were measured, in the excitation energy range of 5.6–30 keV, by using high-brilliance undulator radiation. The obtained intensity ratios, the excitation-energy independent Lβ4/Lβ3, Lη/Lβ1, Lι/Lα1,2, Lβ6/Lα1,2 and Lβ2,15/Lα1,2 as well as the excitation-energy dependent Lβ1/Lα1,2, Lβ3/Lα1,2 and Lβ3/Lβ1, were compared with theoretical calculations, in which the calculations were performed by applying various subsets of the L subshell fluorescence yields and Coster–Kronig yields. Deviations of the theoretical calculations from the experimental results call on improvements in theory for the emission rates. We have also surveyed the Lα1,2 related x-ray hypersatellite lines in the photoinduced Ba L x-ray spectrum.

M ξ, M αβ, M γ and M m X-ray production cross-sections for elements with 71⩽ z⩽92 at 5.96 keV photon energy

The M ξ, M αβ, M γ and M m X-ray production (XRP) cross-sections have been measured for the elements with 71⩽ Z⩽92 at 5.96 keV incident photon energy satisfying E M1< E inc< E L3, where E M1(L3) is the M 1(L 3) subshell binding energy. These XRP cross-sections have been calculated using photoionization cross-sections based on the relativistic Dirac–Hartree–Slater (RDHS) model with three sets of X-ray emission rates, fluorescence, Coster–Kronig and super Coster–Kronig yields based on (i) the non-relativistic Hartree–Slater (NRHS) potential model, (ii) the RDHS model and (iii) the relativistic Dirac–Fock (RDF) model. For the third set, the M i ( i=1–5) subshell fluorescence yields have been calculated using the RDF model-based X-ray emission rates and total widths reevaluated to incorporate the RDF model-based radiative widths. The measured cross-sections have been compared with the calculated values to check the applicability of the physical parameters based on different models.

L i ( i=1–3) subshell fluorescence and Coster-Kronig yields for elements with 70⩽ Z⩽92

The atomic inner-shell vacancy decay processes comprised of radiative and nonradiative transitions are characterized by the fluorescence, Auger and Coster-Kronig yields. We present a review of our recent measurements of the L i ( i=1, 2, 3) sub-shell fluorescence yields ( ω i ) and the L 1–L 3 Coster-Kronig transition probabilities ( f 13) for elements with 70⩽ Z⩽92 following photoionization. The comparison of the measured ω i and f 13 values with the theoretical ones, based on the relativistic Dirac–Hartree–Slater (RDHS) model calculations, indicated the need for more refined calculations of transition probabilities for different Coster-Kronig transitions.

Line-resolvedM-shell x-ray production cross sections of Pb and Bi induced by highly charged C and F ions

Measurement on the $M$-shell x-ray production cross sections are reported for Pb and Bi induced by the highly charged F (only on Pb) and C ions (on both). The energy of the incident ions was varied between 20 and $102\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$. We have derived the absolute cross sections for $M\ensuremath{\alpha}\ensuremath{\beta}$ and $M\ensuremath{\gamma}$ lines as well as the total $M$ x-ray cross sections. The measured cross sections are compared with available theoretical calculations, namely, the ECPSSR based on the perturbed-stationary state approximation including the effects due to the increased binding energy, Coulomb deflection $(C)$, energy-loss $(E)$, and relativistic $(R)$ wave function. The energy shifts and the intensity ratios of $M\ensuremath{\alpha}\ensuremath{\beta}$ and $M\ensuremath{\gamma}$ lines are shown to depend on the projectile atomic number. The $M\ensuremath{\gamma}$ x-ray cross sections are unusually higher compared to the ECPSSR prediction that is primarily attributed to a dramatic enhancement in the ${M}_{3}$-subshell fluorescence yield owing to multiple vacancies in $N$ subshells. This enhancement has been quantified and it is shown that the enhancement depends on the projectile atomic number. In addition we have derived the x-ray cross section arising due to $M\text{\ensuremath{-}}K$-shell electron transfer from a study of a charge state dependence of $M$-shell x-ray yields.

Experimental determination of L subshell fluorescence yields of Ba, La and Pr using synchrotron radiation

L subshell fluorescence yields ω1, ω2 and ω3 have been measured for Ba, La and Pr elemental targets. The characteristic L X-ray photons, induced in the targets by synchrotron radiation, were measured with a Si(Li) detector coupled to multichannel analyzer. Measured L subshell fluorescence yields have been compared with theoretical values, compilation data and other experimental data.

Fit values of N subshell fluorescence yields and Coster?Kronig yields for elements with 38$les;Z$les;103

Most probable values of Coster–Kronig (CK) transition probabilities (S 12 , S 13 , S 14 , S 15 , S 1,67 , S 23 , S 24 , S 2,67 , S 34 , S 35 , S 35 , S 3,67 , S 45 and S 4,67 ) and N i subshell fluorescence yields (N 1 , N 2 , N 3 , N 4 , N 5 and N 67 ) have been determined by using least-squares fitted to obtain the polynomials, which is plotted by using the McGuire's values (Phys Rev A 9(5) (1974) 1840), representing them as a function of atomic number. The S ij represents the N subshell vacancy transitions from i th subshell to j th subshell. The obtained values of N i subshell fluorescence yields—N 1 , N 2 , N 3 , N 4 , N 5 , N 67 , and CK transition probabilities—S 12 , S 13 , S 14 , S 15 , S 1,67 , S 23 , S 24 , S 2,67 , S 34 , S 35 , S 35 , S 3,67 , S 45 and S 46 are presented.

Fit values of N subshell fluorescence yields and Coster–Kronig yields for elements with 38⩽ Z⩽103

Most probable values of Coster–Kronig (CK) transition probabilities (S 12, S 13, S 14, S 15, S 1,67, S 23, S 24, S 2,67, S 34, S 35, S 35, S 3,67, S 45 and S 4,67) and N i subshell fluorescence yields (N 1, N 2, N 3, N 4, N 5 and N 67) have been determined by using least-squares fitted to obtain the polynomials, which is plotted by using the McGuire's values (Phys Rev A 9(5) (1974) 1840), representing them as a function of atomic number. The S ij represents the N subshell vacancy transitions from ith subshell to jth subshell. The obtained values of N i subshell fluorescence yields—N 1, N 2, N 3, N 4, N 5, N 67, and CK transition probabilities—S 12, S 13, S 14, S 15, S 1,67, S 23, S 24, S 2,67, S 34, S 35, S 35, S 3,67, S 45 and S 46 are presented.

Measurement of the L3 to Mi, Ni and Oi subshells radiative transition probabilities of elements in the atomic number range 73 ≤ Z ≤ 92

The L3 subshell x-ray intensity ratios for Ta, W, Re, Au, Hg, Tl, Pb, Th and U have been measured using an Am-241 radioisotope. Radiative transition probabilities of L3 to Mi, Ni and Oi subshells were measured by using L3 x-ray intensity ratios and Li subshell fluorescence yields. For this measurement, the new equations were used in this study. The experimental results were compared with the relativistic Hartree–Slater values of Scofield.

Measurement of L X-ray production cross sections and Li subshell fluorescence yields

L i ( i=1, 2 and 3) X-ray production cross sections have been measured for 14 elements in the atomic number range 55≤ Z≤81 at 15.73 keV. The values of L i subshell fluorescence yields ( ω 1, ω 2 and ω 3) have been determined using the presently measured X-ray production cross sections and the theoretical L i subshell photoionization cross sections values, Coster–Kronig transition probabilities and radiative emission rates. The measured X-ray production (XRP) cross-sections and fluorescence yield values were compared with the theoretical and semi empirical values, respectively.

L i ( i=1,2,3) subshell X-ray production cross-sections and fluorescence yields for Ir, Pt, Pb and Bi

The L i ( i=1,2,3) subshell X-ray production (XRP) cross-sections were measured for 77Ir, 78Pt, 82Pb and 83Bi following direct ionization in the L i ( i=1,2,3) subshells by the 59.54 keV γ-rays and the L 3 subshell by the Br/Rb/Sr/Y K X-rays. The photon sources consisting of an 241Am source in (i) the direct excitation mode and (ii) the secondary excitation mode together with the KBr/RbNO 3/SrCO 3 /Y secondary exciter and an Si(Li) detector were used. The L i ( i=1,2,3) subshell fluorescence yields ( ω i ) for these elements were deduced using the measured XRP cross-sections and the L i subshell photoionization cross-sections based on the Hartree–Fock–Slater model. The measured ω 1 values are found to be higher upto 50% than those based on the relativistic Dirac–Hartree–Slater (RDHS) calculations, while the ω 2 and ω 3 values exhibit good agreement. The predicted jump in the RDHS based ω 1 values from 77Ir to 78Pt due to onset of intense L 1–L 3M 4 CK transition is not observed.

Photon-induced L-subshell Auger yields for some elements in the atomic number range 55⩽ z⩽92 using a S(Li) detector

L -subshell fluorescence and Auger yields for the elements Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd Tb, Dy, Ho, Er, Yb, Lu, Hf, Ta, W, Os, Pt, Au Hg, Tl, Pb, Bi, Th and 92U have been measured at the 59.54 keV γ-ray emission excitation energy from an 241Am radioactive point source of strength 3.7 GBq (100 mCi) using an Si(Li) detector. The L-subshell Auger yields a 1, a 2 and a 3 have been measured using experimental L -subshell fluorescence yields ( ω 1, ω 2 and ω 3) and Coster–Kronig transition probabilities. Our experimental values have been fitted to a third-order polynomial as a function of atomic number.

M-subshell x-ray production cross sections of Au induced by highly charged F, C, and Li ions and protons: A large enhancement in theM3fluorescence yield

M-subshell x-ray production cross sections are measured for Au, induced by F ions in the energy range of 20 to 102 MeV. For a comparative study the measurements are also carried out for protons, He, Li, C ions at a few energies. We have derived the absolute cross sections for $M\ensuremath{\alpha}\ensuremath{\beta}$ and $M\ensuremath{\gamma}$ x rays as well as the total M x-ray cross sections. The intensity ratios, $I(\ensuremath{\gamma})/I(\ensuremath{\alpha}\ensuremath{\beta}),$ of the $M(\ensuremath{\gamma})$ and $M(\ensuremath{\alpha}\ensuremath{\beta}),$ as well as the energy shifts of these lines signifying multiple vacancies in outer shells have also been studied as a function of projectile atomic number. The measured cross sections are compared with available theoretical calculations, namely, the ECPSSR based on the perturbed stationary state (PSS) approximation including the effects due to the increased binding energy, Coulomb deflection (C), energy loss (E), and relativistic (R) wave function. In case of the $M\ensuremath{\gamma}$ the measured cross sections are much higher compared to the ECPSSR prediction which is attributed to a dramatic enhancement in the ${M}_{3}$-subshell fluorescence yield owing to multiple vacancies in N subshells. The enhancement strongly depends on the projectile atomic number.

Determination of L 2 and L 3 subshell fluorescence yields of some elements in the atomic number range 22⩽ Z⩽62

L 2 and L 3 subshell fluorescence yields of some elements in the intermediate atomic number region were obtained using the K shell fluorescence yields and K α1 and K α2 line widths. The present results are compared with semi empirical values and found to be in agreement.

Determination of L 2 to L 3 Coster–Kronig yield of Pr

Atomic L shell Coster–Kronig yields ( f 23) for Pr was determined semiemprically. Experimental measurements were carried out using a Si(Li) detector and a Fe-55 radioisotope. The values of f 23 of Pr was found using experimental L α X-ray production cross section, theoretical L 2 and L 3 subshell photoionization cross section, L 3 subshell fluorescence yield and L α X-ray fraction in L 3 subshell X-rays. The present result was compared with theoretically predicted and semiempirical value.

Determination of level widths and fluorescence yields of some atomic sub-shells for Th and U

The level widths and fluorescence yields of some atomic sub-shells were determined using L1, L2 and L3 sub-shell fluorescence yields and linewidths of some L X-rays. For this measurement, the L3l, L3α, L3β, L2β, L2γ, L1β, L1γ, Lβ, Lγ, L1x, L2x and L3x X-ray production cross sections in U and Th have been measured using the 59.5 keV incident photon energy. The measurements were performed using Am-241 radioisotopes as photon sources and a Si(Li) detector. The L X-rays are resolved with a new analytical method. The obtained L3l, L3α, L3β, L2β, L2γ, L1β, L1γ, Lβ, Lγ, L1X, L2X, and L3X X-ray production cross sections were compared with the theoretical calculations using the most reliable theoretical values of Li (i = 1, 2, 3) sub-shell photoionisation cross sections, fluorescence yields, X-ray emission rates and Coster–Kronig transition probabilities. The measured Li, Mi and Ni sub-shell fluorescence yields were compared with the semi-empirical and theoretical values. Further, obtained level widths were compared with the other experimental and theoretical values. The results in the present paper are found to be in good agreement with calculated values.