Coster-Kronig Yields Research Articles

The Coster–Kronig L shell yield f23 of Ho and Tm

The L shell Coster–Kronig yield f23 has been measured for Z = 67 and Z = 69 by a method employing fluorescence X-ray excitation with a 241Am source, the use of Sm and Gd critical absorption filters, and Kα–Lα coincidences. The results (0.143 ± 0.010 and 0.148 ± 0.007 respectively) are in good agreement with the calculations of Chen and Crasemann which made use of an independent particle model and a Green–Sellin–Zachor potential.

L-shell x-ray production cross sections forO16ions on Ce, Pr, Sm, Eu, Dy, and Ho: 0.50 to 2.25 MeV/amu

L-shell and individual x-ray production cross sections for 8--36-MeV oxygen ions on thin solid targets of Ce, Pr, Sm, Eu, Dy, and Ho are measured and compared with predictions of theories of direct Coulomb ionization. In comparing theory and experiment, we use, with reasonable justification, fluorescence yields, Coster-Kronig yields, and radiative widths obtained from single-hole initial configurations. The theoretical treatment which provides the best overall fit to the data is the plane-wave Born approximation with corrections for Coulomb deflection of the projectile and increased binding of the target electrons. The effects of multiple ionization are examined through measurement of x-ray energy shifts as measured with Si(Li) detectors and by vacuum crystal- spectrometer measurements of L x-ray spectra produced by 3-MeV proton and 25-MeV oxygen-ion bombardment of a thick La target.

Cross sections forLx-ray production andL-subshell ionization by MeV electrons

A systematic study of $L$ x-ray production and $L$-subshell ionization by MeV electron impact has been made. Cross sections were measured for 14 elements from Ba ($Z=56$) to ($Z=83$) at electron bombarding energies of 1.04, 1.39, and 1.76 MeV. Within the error limits there is no dependence on the electron energy. At all energies, measured $L$ x-ray production cross sections exhibit a gradual increase with atomic number. For the heavier elements, typical average values for the $L\ensuremath{\alpha}$, $L\ensuremath{\beta}$, and $L\ensuremath{\gamma}$ group are 70, 55, and 9 b, respectively. $L$-subshell ionization cross sections were derived from the $L\ensuremath{\alpha}$, $L\ensuremath{\beta}$, and $L\ensuremath{\gamma}$ x-ray production cross sections with the use of theoretical $L$-subshell fluorescence yields, Coster-Kronig yields, and radiative branching ratios. The total $L$-shell ionization cross section drops from 1200 b at Ba ($Z=56$) to 380 b at Bi ($Z=83$) with individual $L$-subshells contributing roughly in proportion to their electron number. The measured cross sections are in good agreement with the predictions of the binary-encounter collision model of Gryzi\ifmmode \acute{n}\else \'{n}\fi{}ski.

L- andM-shell electron shake-off accompanying alpha decay

The ${L}_{\mathrm{I}}$-, ${L}_{\mathrm{II}}$-, ${L}_{\mathrm{III}}$-, and $M$-shell vacancy distributions accompanying electron shake-off in the $\ensuremath{\alpha}$ decay of $^{210}\mathrm{Po}$ have been measured by $\ensuremath{\alpha}$-x-ray two parameter coincidence techniques. The ionization probabilities and the errors due to our measurements were (5.11\ifmmode\pm\else\textpm\fi{}0.40, 0.62\ifmmode\pm\else\textpm\fi{}0.06, and 1.50\ifmmode\pm\else\textpm\fi{}0.19) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$ for the ${L}_{\mathrm{I}}$, ${L}_{\mathrm{II}}$, and ${L}_{\mathrm{III}}$ subshells, respectively, and (1.8\ifmmode\pm\else\textpm\fi{}0.4) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}2}$ for the $M$ shell. Possible errors in tabulated fluorescence and Coster-Kronig yields could increase the uncertainties to (1.7, 0.5, 0.8) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$ and 0.6 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}2}$, respectively. The energies and peak shapes of the $\ensuremath{\alpha}$ groups in coincidence with $L\ensuremath{\alpha}$, $L\ensuremath{\beta}$, $L\ensuremath{\gamma}$, and $M$ x rays were also measured. The coincident groups were, respectively, 12.6\ifmmode\pm\else\textpm\fi{}1.4, 13.8\ifmmode\pm\else\textpm\fi{}1.4, 17.6\ifmmode\pm\else\textpm\fi{}2.1, and 3.1\ifmmode\pm\else\textpm\fi{}1.0 keV lower in energy than the $^{210}\mathrm{Po}$ ${\ensuremath{\alpha}}_{0}$ peak. Theoretical calculations by Hansen are in closer agreement with the experimental values for the $L$ subshells than Migdal's theory, but discrepancies of about a factor of 2 still exist.RADIOACTIVITY $^{210}\mathrm{Po}$; measured $\ensuremath{\alpha}\ensuremath{-}L$ and $\ensuremath{\alpha}\ensuremath{-}M$ x-ray coin. Deduced ${L}_{\mathrm{I}}$, ${L}_{\mathrm{II}}$, ${L}_{\mathrm{III}}$, $M$ electron shake-off abundances, energy distribution.

ArgonL-shell ionization by 50- to 600-keVH+,D+,H2+, andHe+impact

Production of Auger electrons from the Ar $L$ shell were studied in scattering experiments with 50- to 600-keV ${\mathrm{H}}^{+}$, ${\mathrm{D}}^{+}$, $\mathrm{H}_{2}^{}{}_{}{}^{+}$, and ${\mathrm{He}}^{+}$ impact on Ar. Electrons ejected at 150\ifmmode^\circ\else\textdegree\fi{} with respect to the incident beam were measured using electrostatic parallel-plate spectrometers. Sets of electron spectra were acquired at different resolutions of 0.35-, 1.4-, and (1.7-2.4)-eV full width of half-maximum. Branching ratios for normal transitions from initial ${L}_{2}$ and ${L}_{3}$ vacancy states are compared with results of other authors. Satellite structures in the spectra are analyzed to determine probabilities for the excitation of multiple-vacancy states ${L}_{23}{M}^{i}$. Intensities of Auger electrons from the ${L}_{1}$ and ${L}_{23}$ shell are compared for an evaluation of the ${L}_{1}$-shell Coster-Kronig yield. Total cross sections for Ar $L$-shell ionization are obtained by integration of the Auger spectra and cross-section ratios are studied for ${\mathrm{He}}^{+}$ and ${\mathrm{D}}^{+}$ impact.

L1subshell yields of elements with Z=74, 75, 77, 79 and 90

Coster Kronig (f12) and fluorescence ( omega 1)L1 subshell yields of tungsten, rhenium, iridium, gold and thorium have been determined by comparing the relative intensities of the L2 satellites with the L1 and L2 X-ray lines.

The role of Coster-Kronig transitions in the ionization of surface atoms

Since Coster-Kronig transitions for isolated atoms are often characterized by higher transition rates than other types of Auger emission, it is important to consider the quantitative effect of these transitions on the Auger electron spectroscopy of solid surfaces. We find that cross sections for the electron impact ionization of L and M shells of surface atoms are augmented by core electron vacancy production due to Coster-Kronig transitions. In the case of L2,3 shell ionization of adsorbed Cl, and L1 contribution is calculated to be about 17% of the total cross section for incident electron energies which exceed four times the L2,3 ionization energy. The M1 and M2,3 ionizations account for about 25% of the total M4,5 ionization cross section for Ba when the energies of the incident electrons exceed the subshell ionization thresholds. Calculated cross sections exhibit good agreement with experimental values for the above elements when the effects of Coster-Kronig transitions are included. It is also shown that Coster-Kronig yields may be determined by combining measured secondary electron currents corresponding to respective subshell ionizations with calculated cross sections.

LX-ray Spectra and E2 Internal Conversion Coefficients in Radon and Radium

The X-ray spectra resulting from the internal conversion of electric quadrupole transitions following the alpha decay of Th230 and Ra226 were analysed with a Si (Li) spectrometer. From the knowledge of the Coster-Kronig and fluorescence yields, the internal conversion coefficients of the E2 transitions from the first excited states in Ra226 and Rn222 could be deduced. Results are in good agreement with theoretical values.

Coster-Kronig and fluorescence yields for the L2and L3subshells in the high-Z region

High resolution intrinsic Ge(HP) and Si(Li) X-ray detectors have been used in coincidence to determine L2 and L3 subshell fluorescence and Coster-Kronig yields at Z=86, 88, and 94. The results are: nu 2=0.498+or-0.028, omega 2=0.459+or-0.025, f23=0.105+or-0.011, omega 3=0.384+or-0.020 at Z=86; nu 2=0.516+or-0.036, omega 2=0.493+or-0.030, f23=0.053+or-0.026, omega 3=0.408+or-0.027 at Z=88; and nu 2=0.627+or-0.036, omega 2=0.513+or-0.022, f23=0.226+or-0.016, omega 3=0.509+or-0.029 at Z=94. Together with previously published data, these results provide evidence that in the L2-L3 Coster-Kronig process, ejection of an M5-subshell electron is energetically possible at Z=92 and that M4- and M5-subshell electron ejection are both possible at Z=94. These conclusions are shown to be consistent with the L X-ray line width measurements of Merrill and DuMond (1961) and with the formula put forward by Coster and Kronig (1935) for the ejected electron energy. Recent theoretical predictions of the L-subshell yields compare favourably with experiment, except when Coster-Kronig transitions close to an energy threshold are involved.

TheL 1 subshell fluorescence and Coster-Kronig yields forZ=96

High resolution Si(Li)-Si(Li) and Si(Li)-Ge(Li) detector arrangements have been used to studyL x-ray spectra in coincidence withL-shell internal conversion electrons, gamma rays, andK x-rays emitted in249Cf decay. TheL1 subshell fluorescence and Coster-Kronig yields determined forZ=96 from these spectra are ω1=0.25±0.06,f12≦0.10, andf13=0.69 ±0.08. The presence of theL1-L3 radiative transition is also further confirmed in this work.

Use of 155Eu in the Measurement of Gd L Subshell Yields

The subshell fluorescence yields ω2 and ω3 and the Coster–Kronig yield f23 have been measured for Gd by the method of coincidence study of the X rays emitted by 155Eu.The result is ω2 = 0.182 ± 0.008, ω3 = 0.187 ± 0.006, and f23 = 0.223 ± 0.011. The values for ω2 and ω3 are close to theoretical predictions and to the experimental results of other workers on the neighboring element Tb. However, there is serious disagreement in the f23 values.

L-subshell fluorescence and coster-kronig yields atZ=92 and the decay of235Np

TheK andL x-rays emitted in the decay of235Np have been studied with high resolution Ge(HP) and Si(Li) detectors in coincidence, in order to obtain theL2 andL3 subshell fluorescence and Coster-Kronig yields atZ=92. The results are:v2=0.630±0.036, ω2=0.560±0.033,f23=0.147±0.010, and ω3=0.481±0.029. Results for theL1 subshell were derived from singles spectra, by assuming a value off13 of 0.67, and are:v1=0.54±0.04, ω1=0.21±0.04, andf12<0.07. With the same assumption, theL1/K electron capture ratio and decay energyQ ec for235Np were found to be 29.0±3.6 and 123.6±0.7 keV, respectively. RelativeL x-ray intensities forZ=92 also were measured and are compared with the theory of Scofield and with recent diffraction experiments. Electron ejection from theL shell during235Np decay has been studied byL x-ray-L x-ray coincidences and found to occur with a probability of (1.3±1.0) × 10−4 per disintegration.

Mean L-shell x-ray fluorescence yields atZ=47, 60, and 63

MeanL-shell x-ray fluorescence yields $$(\bar \omega _L )$$ have been measured by observingK andL x-ray spectra emitted in the decay of109Cd,145Pm, and153Gd with a high resolution Si(Li) x-ray detector. The results forZ=47, 60, and 63 are as follows: $$\bar \omega _L $$ =0.0425±0.0064, 0.131±0.017, and 0.142±0.023, respectively. Additional values of $$\bar \omega _L $$ from this laboratory atZ=55, 56, 57, 59, and 65 are also tabulated as are previous experimental values atZ=47, 60, and 63. For comparison, theoretical estimates of $$\bar \omega _L $$ were computed using theoreticalL-subshell fluorescence and Coster-Kronig yields, together with subshell vacancy distributions calculated from the literature. The theoretical estimates atZ=47, 60, and 63, based on the subshell calculations of Chen, Crasemann, and Kostroun, agree well with experiment.

M-Subshell Fluorescence Yields and theL1−L3Radiative Transition atZ=93 and 96fromAm241andCf249Decays

High-resolution Ge(Li) and Si(Li) x-ray spectrometers and a wall-less anticoincidence multiwire proportional counter were used for coincidence measurements between various $K$ and $L$ x rays and $M$ x rays of Np (Z=93) and Cm ($Z=96$) following $\ensuremath{\alpha}$ decay of ${\mathrm{Am}}^{241}$ and ${\mathrm{Cf}}^{249}$, respectively. The effect of multiple vacancies in the $M$ shell was taken into account in the determination of the following mean $M$-subshell fluorescence yields: ${\ensuremath{\nu}}_{1}^{M}=0.065\ifmmode\pm\else\textpm\fi{}0.014$, ${\ensuremath{\nu}}_{2}^{M}=0.080\ifmmode\pm\else\textpm\fi{}0.029$, ${\ensuremath{\nu}}_{4}^{M}=0.062\ifmmode\pm\else\textpm\fi{}0.005$, ${\ensuremath{\nu}}_{4,5}^{M}=0.065\ifmmode\pm\else\textpm\fi{}0.012\ensuremath{\approx}{\ensuremath{\omega}}_{5}^{M}$ at $Z=93$; and ${\ensuremath{\nu}}_{1}^{M}=0.081\ifmmode\pm\else\textpm\fi{}0.016$, ${\ensuremath{\nu}}_{2}^{M}=0.068\ifmmode\pm\else\textpm\fi{}0.023$, ${\ensuremath{\nu}}_{3}^{M}=0.062\ifmmode\pm\else\textpm\fi{}0.019$, ${\ensuremath{\nu}}_{4}^{M}=0.080\ifmmode\pm\else\textpm\fi{}0.006$, and ${\ensuremath{\nu}}_{4,5}^{M}=0.075\ifmmode\pm\else\textpm\fi{}0.012\ensuremath{\approx}{\ensuremath{\omega}}_{5}^{M}$ at $Z=96$. The close agreement of the various mean $M$-subshell fluorescence yields with that of the ${M}_{4,5}$ subshells for each element indicates that Coster-Kronig transitions are very strong in the $M$ shell. Including earlier measurements of mean $M$-shell fluorescence yields at lower $Z$, corrected for multiple vacancies, and accepting Bhalla's theoretical calculations of radiative ${M}_{4,5}$-subshell widths, one concludes that the nonradiative widths of the ${M}_{4,5}$ subshells are essentially constant from $Z=76 \mathrm{to} 96$. Comparison of fluorescence yields of the $K$ shell and the ${L}_{3}$ and ${M}_{4,5}$ subshells at the same energy of the principal radiative transition (i. e., at different values of $Z$ indicates that the ratio of radiative to Auger widths decreases from the $1{s}_{\frac{1}{2}}$ to $2{p}_{\frac{3}{2}}$ state, but remains constant from $2{p}_{\frac{3}{2}}$ to $3{d}_{\frac{5}{2}}$. The resolution of the Si(Li) detector was sufficient to separate the radiative transitions from fillings of the ${M}_{1,2}$- and ${M}_{3,4,5}$-subshell groups, so that from $K$ and $L$ x-ray coincidences with the ${M}_{1,2}$ group of x rays, it was possible to determine the following quantities: ${\ensuremath{\omega}}_{1}^{M}+{f}_{12}^{M}{\ensuremath{\omega}}_{2}^{M}=({2.0}_{\ensuremath{-}2.0}^{+3.1})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3} \mathrm{and} ({7.5}_{\ensuremath{-}7.5}^{+8.9})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ at $Z=93 \mathrm{and} 96$, respectively, and ${\ensuremath{\omega}}_{2}^{M}=({4.6}_{\ensuremath{-}4.6}^{+5.1})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ at $Z=96$. Thus, about 94% of ${M}_{2}$-subshell vacancies undergo Coster-Kronig shifts to higher subshells before filling from $N$ and higher major shells occurs. Observation of the radiative ${L}_{1}\ensuremath{-}{L}_{3}$ transition was made for the first time in the high-$Z$ region, and its intensity is in reasonable agreement with extrapolated theoretical predictions (6-7% of x rays filling ${L}_{1}$-subshell vacancies). The radiative fraction ${\ensuremath{\omega}}_{13}^{L}$ in the Coster-Kronig yield ${f}_{13}^{L}$ is found to be about 2% in the region of $Z=93\ensuremath{-}96$, and ${\ensuremath{\omega}}_{13}^{L}=0.011\ifmmode\pm\else\textpm\fi{}0.005 \mathrm{and} 0.009\ifmmode\pm\else\textpm\fi{}0.005$ at $Z=93 \mathrm{and} 96$, respectively. The absolute emission rate of $M$ x rays from ${\mathrm{Am}}^{241}$ was measured with multiwire and single-wire proportional counters, and values are found of (6.35 \ifmmode\pm\else\textpm\fi{} 0.60) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}2}$ $M$ x rays per $\ensuremath{\alpha}$ decay and 0.470 \ifmmode\pm\else\textpm\fi{} 0.045 $M$ x rays per ${L}_{\ensuremath{\alpha}}$ x ray. These intensities were used in determinations of efficiency at 3.25 keV of the semiconductor x-ray detectors.

L 2 andL 3 subshell fluorescence and Coster-Kronig yields forZ=96 from the decay of249Cf

L 2 andL 3 subshell fluorescence and Coster-Kronig yields forZ=96 from the decay of249Cf

BismuthL-Subshell Fluorescence and Coster-Kronig Yields from Decay ofPb210(RaD)

Revised values of $L$-subshell fluorescence and Coster-Kronig yields at $Z=83$ are reported here, based on a recalculation of data previously obtained. The revised values are as follows: ${\ensuremath{\omega}}_{2}=0.38\ifmmode\pm\else\textpm\fi{}0.02$, ${a}_{2}=0.45\ifmmode\pm\else\textpm\fi{}0.02$, ${\ensuremath{\omega}}_{3}=0.340\ifmmode\pm\else\textpm\fi{}0.018$, ${a}_{3}=0.660\ifmmode\pm\else\textpm\fi{}0.018$, and ${n}_{{L}_{2}M}=1.34\ifmmode\pm\else\textpm\fi{}0.14$. The major change is in the value ${\ensuremath{\omega}}_{2}$, which now agrees much better with the trend of values for neighboring elements. The revised value of the ionization multiplicity ${n}_{{L}_{2}M}$ is in good agreement with a recent theoretical value of 1.29 given by E. G. McGuire. No change results in the previous values for the ${L}_{1}$-subshell quantities given by H. U. Freund and R. W. Fink.

K AND L SHELL FLUORESCENCE AND AUGER YIELDS AND AUGER ELECTRON SPECTROSCOPY

Our recent calculations of K and L shell fluorescence and Coster-Kronig yields are reviewed. The computed KLL electron intensity ratios are compared with experiment. The L-shell Auger and Coster-Kronig electron intensity spectra are compared with measurements on Ar and U.

Decay of 159Dy: L-subshell X-ray fluorescence and Coster-kronig yields at Z = 65; branching ratio, and K-conversion of the 58 keV transition in 159Tb

Ultra-high resolution Ge(Li) and Si(Li) detectors have been used to study L-subshell X-ray fluorescence and Coster-Kronig yields in Tb from the EC decay of carrier-free 159Dy. From singles and L X-ray spectra in coincidence with Kα1 and Kα2 X-rays, the following L-subshell quantities were obtained: ω3 = 0.188±0.016, ω2 = 0.160±0.018, f23 = 0.090±0.014, v1 = 0.29±0.08, v2 = 0.177±0.019, s2 = 0.204±0.024, s3 = 0.170±0.024, and ωKL = 0.184 ±0.016. Corrections for nuclear cascading were made experimentally using an L X-ray spectrum gated by Kβ X-rays. Angular correlation effects were taken into account. Taking a theoretical value of s1 = 0.270, the present experiment allows estimates to be made of the following L1 subshell quantities: ω1 = 0.18±0.04, ƒ12 = 0.41±0.36 and ƒ13 = 0.43±0.28. K X-ray spectra in coincidence with K X-rays and with the 58.0 keV γ-ray were taken to determine the EC branching to the 58.0 keV level (26.8±1.4%) and the K-conversion coefficient of the 58.0 keV transition, αK = 9.3±0.5, which agrees with the theoretical value for an M1 + 1.4% E2 transition.

Electron capture decay of181W: L subshell fluorescence and Coster-Kronig yields in Ta

The TaL x-ray spectrum from the 140 d electron capture decay of181W was studied with high resolution semiconductor detectors and fast coincidence techniques. Measurement ofL x-ray-K x-ray andL x-ray—γ-ray coincidence rates yielded the followingL shell fluorescence and Coster-Kronig yields and radiative decay branching ratios: ω2=0.250±0.013, ω3=0.228±0.013 (corrected for angular correlation effects),f23=0.180±0.007,v1=O.218±0.016,s3=0.205+-0.010,s2=0.215+-0.010,f13+f12f23=0.36+-0.02, and ω1+f12ω2=0.14±0.02, from which upper limits were obtained off13<0.36 and ω1<0.14.

Fluorescence and Coster - Kronig Yields ofLSubshells in Hg from the Decay ofAu198andTl204

Coincidences between $L$ x rays and $K\ensuremath{\alpha}$ x rays, emitted during the filling of $K$ and $L$ vacancies in Hg in the decay of $^{198}\mathrm{Au}$ and $^{204}\mathrm{Tl}$, are measured with high-resolution Si(Li) and Ge(Li) x-ray spectrometers in a fast-coincidence arrangement. The following $L$-subshell fluorescence and Coster-Kronig yields are measured: ${\ensuremath{\omega}}_{2}=0.316\ifmmode\pm\else\textpm\fi{}0.010$, ${\ensuremath{\omega}}_{3}=0.300\ifmmode\pm\else\textpm\fi{}0.010$, and ${f}_{23}=0.190\ifmmode\pm\else\textpm\fi{}0.010$.