An energy value of 9406.3(5) eV was determined for the 9.4 keV (M1+E2) nuclear transition in 83Kr by the internal conversion electron spectrometry method. This value agrees within 1σ with the most ...precise values determined previously for which their weighted mean amounts to 9405.9(2) eV. A value of 22745.3(2) eV was obtained directly from our experimental data for the energy difference between the 32.1 keV and 9.4 keV transitions in 83Kr. Electron binding energies (related to the Fermi level) on the K, L, and M1,2,3 subshells of Kr implanted into a polycrystalline Pt matrix were also derived. They were found to be lower by weighted mean values of 11.6(4) and 1.7(6) eV compared to those for free Kr atoms and for Kr in an evaporated 83Rb layer on Al backing, respectively, and higher by a weighted mean value of 2.9(2) eV than the binding energies in Kr in an evaporated layer on polycrystalline Pt backing.
The 9.2 keV nuclear transition in 227Th was studied in the β−-decay of 227Ac by means of the internal conversion electron spectroscopy to clarify the spin-parity assignment of the ground state and ...the two lowest excited states of 227Th. The transition multipolarity was proved to be of mixed character M1 + E2 and the spectroscopic admixture parameter δ2(E2/M1)=0.695±0.248 (|δ(E2/M1)|=0.834±0.149) was determined. Nonzero value of δ(E2/M1) questioned the present theoretical interpretation of low-lying levels of 227Th. Calculations performed prefer the 1/2+, 3/2+, and 3/2+ sequence instead of the adopted 1/2+, 5/2+ and 3/2+ one for the 0.0, 9.2, and 24.3 keV levels, respectively.
The 9.2 and 24.3 keV nuclear transitions in
227
Th were studied in the
β
-
decay of
227
Ac employing the internal conversion electron spectroscopy. Values of
(
9244.6
±
0.8
)
and
(
24343.1
±
1.1
)
eV ...were determined for their energies. The 24.3 keV transition was found to be of the mixed (M1
+
E2) multipolarity with the spectroscopic admixture parameter
δ
2
(
E
2
/
M
1
)
=
(
0.0116
±
0.0004
)
. Energies of
(
24342.9
±
1.2
)
,
(
28613.3
±
1.7
)
, and
(
37860.2
±
2.0
)
eV were obtained respectively for the 24.3, 28.6, and 37.8 keV transitions in
227
Th by means of the gamma-ray spectroscopy. Natural atomic-level widths of
(
14.1
±
0.5
)
,
(
11.4
±
0.5
)
,
(
6.9
±
0.4
)
,
(
11.4
±
1.4
)
,
(
8.6
±
1.2
)
, and
(
6.0
±
0.7
)
eV for the M
1
-, M
2
-, M
3
-, N
1
-, N
2
-, and N
3
-subshells of thorium, respectively, were derived from conversion electron lines. The cross checking of the energy values of the 9.2, 15.1, and 24.3 keV nuclear transitions obtained by the ICES method is also given.
.
Using the internal conversion electron spectroscopy, the energy of the 15.1 keV
M
1
+
E
2
nuclear transition in
227
Th populated in the
β
-
decay of
227
Ac was determined to be
15098
.
6
±
1
.
0
...eV. This value is more accurate than the present accepted one by a factor of 200. The present uncertainty in the transition multipolarity was removed and it was found to be
M
1
+
E
2
with the admixture
|
δ
(
E
2
/
M
1
)
|
=
0
.
035
±
0
.
006
.
•The KLL Auger electron spectra of Zr and Nb investigated in detail.•Energies, relative intensities, and natural widths of spectrum components determined.•Results of our ab initio multiconfiguration ...Dirac-Hartree-Fock calculations discussed.•An influence of the atomic structure effect on the Zr absolute energies found.•An impact of the relativistic effects on the KL1L2(3P0) transition intensity observed.
The KLL Auger electron spectra of Zr (Z = 40) and Nb (Z = 41) following respectively the electron capture (EC) decay of 90Nb and the de-excitation of the isomeric state of 91mNb were investigated in detail using a combined electrostatic electron spectrometer and radioactive sources prepared by surface sorption on a polycrystalline carbon substrate. For both elements, energies, relative intensities, and natural widths of all the nine well-resolved basic spectrum components were determined and compared with theoretical predictions and with results of previous measurement as well. Results of our ab initio multiconfiguration Dirac-Hartree-Fock calculations are discussed also in relation to the solid-state effect. Indications of an influence of the EC decay on the absolute energy of the KL2L3(1D2) transition (so-called atomic structure effect) in Zr were found. The effect of the retarded current-current interaction on the KL1L2(3P0) transition intensity was observed to be appreciable for the investigated elements in accordance with the prediction.
•The thulium L, M, N, O, and P subshell electron binding energies determined.•Five different matrices of the radioactive 169Yb atoms used in the investigation.•The greatest difference of 4.5±0.1eV in ...the average observed between the matrices.•The published N1, N3, and O2,3 values found to be higher by about 3eV.•Natural widths of the thulium K, L, M, N, and O subshells also determined.
The L1, L2, L3, M1, M2, N1, N3, O1, O2, O3, and P1 subshell electron binding energies (related to the Fermi level) in thulium generated by the electron capture decay of radioactive 169Yb atoms implanted at 30keV into polycrystalline platinum and aluminum foils and deposited by vacuum evaporation on surfaces of polycrystalline platinum, carbon, and aluminum foils were determined by the internal conversion electron spectroscopy. The greatest differences in the electron binding energies (4.5±0.1eV in the average without the P1 shell and 7.0±0.5eV for the P1 shell alone) were found between the matrices of the evaporated ytterbium layer on the aluminum foil and the bulk of the high purity polycrystalline platinum. The thulium electron binding energies in the matrices of the evaporated ytterbium layers on both the platinum and carbon foils and in the aluminum bulk were observed to be the same within the experimental uncertainties. The N1, N3, and O2,3 electron binding energies most frequently presented in data compilations were found to be higher by about 3eV. Natural widths of most of the K, L1, L2, L3, M1, M2, M3, N1, N3, and O1 subshells in Tm in the investigated matrices were also determined. No significant differences in the natural widths were found among the matrices. The results obtained demonstrate that the physicochemical surrounding of the radioactive atoms should be well defined and understandable for any type of electron calibration source particularly in the case of the super stable calibration 83Rb/83mKr electron sources for the KATRIN neutrino mass experiment.
•The K, L1–3, M1–3 electron binding energies in Kr in the Pt bulk determined.•The K, L1–3, M1–3 electron binding energies in Kr in an evaporated Rb layer obtained.•The krypton K, L1–3, M1 atomic ...level widths determined for the both host matrices.•The Kr KL2L3(1D2) Auger transition energies measured for the both host matrices.•The KL2L3(1D2) energy difference between Rb and Kr in the Pt host measured.•Dirac–Fock calculations of the Kr KLL Auger transitions performed.
The low-energy electron spectra emitted in the radioactive decay of the 83Rb and 83Sr isotopes were measured with a combined electrostatic electron spectrometer. Radioactive sources used were prepared by ion implantation of 83Sr into a high purity polycrystalline platinum foil at 30keV and by vacuum-evaporation deposition of 83Rb on the same type of foil. From the measured conversion electron spectra, the electron binding energies (referenced to the Fermi level) for the K, L1, L2, L3, M1, M2, and M3 shell/subshells of krypton in the platinum host were determined to be 14316.4(12), 1914.3(9), 1720.3(9), 1667.6(9), 281.5(9), 209.6(13), and 201.2(15)eV, respectively, and those for the evaporated layer were observed to be lower by 0.7(1)eV. For both host matrices, values of 2.3(2), 4.6(2), 1.7(2), 1.3(2), and 3.2(3)eV were obtained for the krypton K, L1, L2, L3, and M1 natural atomic level widths, respectively. The absolute energies of 10838.5(9) and 10839.5(10)eV were measured for the KL2L3(1D2) Auger transition in krypton implanted in Pt and generated in the evaporated rubidium layer, respectively. A value of 601.0(8)eV was measured for the energy difference of the KL2L3(1D2) transitions in Rb and Kr in the Pt host. Multiconfiguration Dirac–Fock calculations of the krypton KLL transition energies and intensities were also performed.
The energy scale of the main spectrometer in the KATRIN tritium project is required to remain stable within ±60 meV at an electron energy of 18.6 keV for two months in order to reach the intended ...sensitivity of 0.2 eV for the rest mass of the electron antineutrino. A natural source of reference electrons with an energy of 17824.3 ± 0.5 eV based on
K
-conversion electrons of the 32-keV nuclear γ-transition in
83m
Kr from the decay of parent
83
Rb was developed for this purpose using precision low-energy nuclear electron spectrometry. The spectroscopic parameters of
83m
Kr/
83
Rb sources fabricated by ion implantation into polycrystalline platinum foils were significantly better than the parameters of vacuum-deposited sources. A large-scale study of the influence of the physicochemical environment of atoms of different radioisotopes in various matrices of vacuum-deposited and implanted radioactive sources on the energy of emitted conversion and Auger electrons and on the structure of the corresponding energy spectra was conducted in the process. The possibility of application of photoelectron sources with a metallic converter as sources of reference electrons for the KATRIN project was also considered.
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