Revision of the109Cd decay data

Combining measurement with the use of a Si(Li) detector and a windowless 4π NaI(T1) detector a new value ofω _K(Ag) equal to 0.84±0.02 has been determined. From the measured ratio of the KX-ray and conversion electron emission rates the relative K-capture probabilityP _K=0.77±0.015 was calculated. Through analysis of data reported in literature and taking into account the new value ofP _K andω _K and the results of the international comparison of absolute activity measurements of¹⁰⁹Cd, the following decay data were chosen for the calculation of yields:ω _K=0.836±0.007;α _T=26.4±0.3; α_K=11.4±0.3; P_K=0.78±0.015. The number of gamma photons per disintegration (gamma-yield) was then determined equal to 0.0365±0.0004; the KX-yield equal to 0.997±0.008; the conversion electrons yield equal to 0.9635±0.0005 and the KX/γ ratio equal to 27.3±0.6.     

Investigation of excitation of Ag atoms in internal conversion of γ rays

Excitation of Ag atoms in the internal conversion of γ rays due to the E3 transition in ^109m Ag has been measured on an anti-Compton spectrometer and a multidimensional-coincidence spectrometer with GeSi(Li) detectors. The probability of double ionization of the K shell is determined to be P _KK =(2.5 ± 0.2) × 10^?4. It is shown that the direct process is dominant in excitation of Ag atoms.     

Inclusive cross sections in the central region and the supercritical pomeron

Using the double-Regge formalism and a supercritical pomeron with α_P(0)=1+Δ, we analyse the energy dependence of inclusive cross sections for negatively charged particles (c⁻) and K_s⁰ at CM rapidity y=0 in the CERN PS-Sp̄pS collider energy range. The values of Δ(c⁻)=0.170±0.008 and Δ(K_s⁰)=0.167±0.024 are found to be very close to each other and compatible with estimates of Δ derived from the total cross sections.     

Results of the search forK-series X-rays from kaonic hydrogen

The X-ray spectrum associated withK ^? stopping in liquid hydrogen was measured with high resolution Si(Li) detectors. The totalK X-ray yield is not larger than 8×10^?4 per stoppedK ^? assuming no line broadening. A weak line pattern was found, which was tentatively ascribed to theK ^? HK-series X-rays. The shift and width of the 1s level, deduced from this pattern, are ε_1s =+270±80 eV andΓ=560±260 eV, respectively.     

Innere Konversion der 161 keV- und 223 keV-Übergänge in133Cs

Using a Ge(Li)-Si (Li)-spectrometer the 161 keV and 223 keV transitions of¹³³Cs were investigated. TheK-conversion coefficients were deduced to beα _K =0.205±0.007 andK-conversion coefficients were deduced to beα _K =0.0743±0.0043, respectively. TheK/L ratio for the 161 keV transition is 4.72±0.37. From theK-conversion coefficients were deduced to beα _K -values,M1 penetration factors ofλ=8.6±3.4 andλ=7.8 _?2.8 ^3.0 were deduced which are inconsistent with known data from angular correlation experiments (λ=40±10 andλ=90±13). The penetration factor fromK/L-measurement for the 161 keV-transition isλ=52±19. A theoretical reinvestigation of the formulas used in the literature appears recommendable. Furthermore, theK/L ratio of the 1770 keV transition of²⁰⁷Pb was determined experimentally to be 5.52±0.54.     

Optical pumping of the metastable 53P0 level of ODD isotopes of cadmium

Metastable 5³P₀ atoms of ¹¹¹Cd and ¹¹³Cd are optically pumped in an atomic beam. Their magnetic resonances are observed with Landé factors g(³P₀, ¹¹¹ Cd) = (1.090±0.003) × 10^-3 and g(³P₀, ¹¹³Cd) = (1.143 ± 0.003) × 10^-3 which are 1.7 times larger than the g-factors of the 5¹S₀ ground state. This large difference arises from a slight mixing of the 5³P₀ level with the 5³P₁ and 5¹P₁ levels through the hyperfine interaction.     

Satellites,hypersatellites and RAE from Ti,V, Cr,Mn and Fe in photoionisation

K x‐ray satellites, hypersatellites and lines due to radiative Auger effect (RAE) of Ti, V, Cr, Mn and Fe were measured after exciting the samples with Ag bremsstrahlung at 35 kV. All the lines were measured with the ‘Spectroscan VY’ spectrometer of Spectron—OPTEL, Russia, in which a curved LiF(200) crystal was used. The spectra were deconvoluted using Voigt functions, and the peak positions of the satellites and hypersatellites were determined with errors of ± (1–5) eV. The energy shifts of the satellite lines with respect to their parent lines were also obtained. Multi‐configuration Dirac–Fock (MCDF) calculations with the inclusion of higher‐order corrections were carried out to predict the peak positions of the satellite and hypersatellite lines. Our data were then compared with our own calculated values and also with the data of others. Our measured energy shifts for K_αL¹, K_αL², K_α^h and K_βL¹, when compared with our MCDF calculations, show a maximum deviation of 8, 12, 2 and 20% respectively. Copyright © 2008 John Wiley & Sons, Ltd.     

Thermal dependence of conduction properties in the Bi2O3Pb2OF2 system

Conduction properties of bismuth-lead oxyfluorides (Bi,Pb)₂(O,F)₃ have been investigated by complex impedance analysis. A special attention has been drawn to a hexagonal solid solution Bi_(1−x)Pb_xO_(1.5−x)F_x (0.45⩽x⩽0.741 at 770 K), which is isostructural with ALa₂O₃. Conductivity values range from 3 × 10⁻⁵ to 3 × 10⁻² (ω cm)⁻¹ at 585 K. A minimum associated with a maximum in activation energy is observed for the composition x = 0.5 i.e. BiPbO₂F.     

7 MeV dipole ground state transitions in 207Pb, 208Pb and 209Bi

The Doppler-broadened 7.117 MeV line from the ¹⁹F(p, αγ)¹⁶O reaction has been used to resonantly excite levels in ²⁰⁸Pb at 7071±2 and 7091±2 keV, in ²⁰⁷Pb at 7186±5 and 7206±5 keV and in ²⁰⁹Bi at 7179±5 and 7202±5 keV. On the basis of angular distribution measurements the 7071 and 7091 keV levels of ²⁰⁸Pb are assigned spins of 1 and assuming 100% ground state branching the widths are calculated to be 31±3 and 17±2 eV respectively. It is suggested that the states in ²⁰⁷Pb and ²⁰⁹Bi arise from the weak coupling of a $\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ neutron hole and an $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ proton respectively to one or the other of the ²⁰⁸Pb levels. The widths obtained in terms of _gΓ_o²/Γ are 15±4 and 25±5 eV for the 7186 and 7206 keV levels of ²⁰⁷Pb and 24±5 and 30±5 for the levels of ²⁰⁹Bi respectively. These values are consistent with the weak-coupling suggestion.     

207Bi L-subshell orbital electron capture probabilities and decay energy

The L₁ subshell orbital electron capture probability P_L1 in the decay of 33.4 y ²⁰⁷Bi to the 2339.89 keV level in ²⁰⁷Pb is measured to be 0.518 ± 0.081 (95% confidence) by a new method in which L₁ subshell characteristic X-rays in the L_γ X-ray peak are observed in an Xγt coincidence mode with 1770.23 keV γ-rays. The value of P_L2is 0.047 ± 0.015 (95% confidence). From these results a value of Q_EC = 39_-8⁺²¹ keV is obtained for capture transitions to the 2339.89 keV level. The absence of K-capture to this level also is established by absence of K X-rays in coincidence with 1770.23 keV γ-rays.     

Measurement of the 15N(α, γ)19F resonances at Ec.m. = 536 keV and 542 keV

The E_c.m. = 536 keV and E_c.m. = 542 keV resonances in the ¹⁵N(α, γ)¹⁹F reaction have been studied using a thick Ti¹⁵N target, determining ωγ = (9.7 ± 2.0) × 10⁻⁵ eV and ωγ < 1 × 10⁻⁵ eV for these two resonances, respectively. For the 542 keV resonance this value is substantially smaller than had been assumed in earlier model calculations, and this reduces the rate of the analog ¹⁵O(α, γ)¹⁹Ne reaction (connecting the Hot CNO cycle and the rp-process) by a factor of ≈ 3 for temperatures in the region of T₉ = 1.     

First observation of K X-rays from pp atoms

K and L series X-rays have been observed from p$\text{p}$ atoms formed in hydrogen gas at NTP in association with annihilations into neutral particles. The total K X-ray yield is (6.5 ± 3.2) × 10^?3 per stopped antiproton. A model-dependent fit of the K X-ray spectrum gives a K_α energy of 8.9±0.3 keV, corresponding to a strong interaction shift of (?0.5±0.3) keV.     

Thermal conductivity and expansion of PbF2 single crystals

In order to check a phenomenon of the negative correlation between ionic and thermal conductivities of solid substances, we studied the thermal conductivity and expansion of cubic PbF₂ single crystals at 50–300 and 5.6–317 K, respectively. We found that lead difluoride had a thermal expansion coefficient α that was equal to (28.5 ± 0.3)10⁻⁶ K⁻¹ at 300 K, and a thermal conductivity coefficient k(T) was equal to 1.40 ± 0.07 W/(m K) at the same temperature. Thus, the thermal conductivity for PbF₂ is the lowest among fluorite-type MF₂ (M = Ca, Sr, Ba, Cd, Pb) thermal conductivities, whereas its fluoride-ion conductivity is the highest one among MF₂ (M = Ca, Sr, Ba, Cd, Pb) ionic conductors.

     

P–V–T equation of state of rhodium oxyhydroxide

A high pressure X-ray diffraction study of RhOOH was carried out up to 17.44?GPa to investigate the compression behavior of an oxyhydroxide with an InOOH-related structure. A fit to the third-order Birch–Murnaghan equation of state gave K₀?=?208?±?6?GPa, and K′?=?9.4?±?1.3. The temperature derivative of the bulk modulus was found to be ?K/?T?=??0.06?±?0.02?GPa K^?1. The refined parameters for volume thermal expansion were α₀?=?2.7?±?0.3?×?10^?5 K^?1; α₁?=?1.7?±?1.1?×?10^?8 K^?2 in the polynomial form (α(T)?=?α_0?+?α₁(T?300)). Our results show that RhOOH is very incompressible, and has a higher bulk modulus than other InOOH-structured oxyhydroxides (e.g. δ-AlOOH, ε-FeOOH, and γ-MnOOH).     

Determination of the kinetic parameters of the isomerization reaction of ethyl isocyanide using HeI photoelectron spectroscopy

The use of HeI photoelectron spectroscopy (PES) for the kinetic study of chemical reactions was introduced previously by us. As another example of the determination of the kinetic parameters of a chemical reaction using the PES method, the isomerization reaction of ethyl isocyanide CH₃CH₂NC → CH₃CH₂CN is investigated. It is found to be first order and the kinetic equations at 193.6, 200.0 and 210.3°C can be expressed as ln R_{466.6 K} = − (7.600 ± 0.026) × 10⁻⁵t − 0.4350; ln R_{473.0 K} = − (1.329 ± 0.032) × 10⁻⁴ − 0.4375 and ln R_{483.3 K} = − (3.170 ± 0.052) × 10⁻⁴ − 0.4354, respectively. The rate constants of the reactions at 193.6, 200.0 reactions at 193.6, 200.0 and 210.3°C are respectively (7.600 ± 0.026) × 10⁻⁵, (1.329 ± 0.032) × 10⁻⁴ and (3.170 ± 0.052) × 10⁻⁴ s⁻¹. The calculated activation energy (E_a) of this isomerization reaction is 38.36 ± 0.32 kcal mol⁻¹. These results are also in excellent agreement with the results obtained by a traditional method. This means that PES is a valuable method for determining the kinetic parameters of chemical reactions. The value of the intercept in the kinetic equations is related to the logarithm of the ratio of the photoionization cross-section of the bands used. This also means that the relative photoionization cross-sections of the bands used for the sample studied are obtained in the kinetic study of a chemical reaction using the PES method.     

X-rays from pionic 3He

Pionic X-ray energies, lorentzian widths, and relative intensities have been measured for the transitions in liquid ³He. The pion-nucleus interaction is found to result in an attractive shift of the 1s level of 27 ± 5 eV and in a lorentzian width of 65 ±12 eV. The measured K_β to K_α intensity ratio is 1.05±0.07.     

Anomalous temperature dependence of the band gap in AgGaSe2 and AgInSe2

The lowest band gaps of AgGaSe₂ and AgInSe₂ single crystals in the temperature range from 90 to 300 K were determined from photoconductivity measurements. Below (above ≈ 120 K in AgInSe₂ and ≈ 125 K in AgGaSe₂ the temperature coefficient of the band gap is +5 × 10⁻⁴ eV/K (−1.5 × 10⁻⁴ eV/K) and +1.1 × 10⁻⁴ eV/K (−4.28 × 10⁻⁴ eV/K), respectively. The positive value is explained with the lattice dilation effect being the dominant mechanism for the band gap variation at the temperatures less than ≈ 120–125 K.     

Measurement of mass and lifetime of hadronically produced charmed F mesons

We have observed three unique decays of F mesons into KKπ and five unique decays of D mesons into KKπ using the NA11 spectrometer together with a telescope of high-resolution silicon microstrip detectors. The mass value obtained for the F meson is (1975 ± 4) MeV, the lifetime (3.2±_1.3^3..0)×10^?13 s.     

High spin states and neutron multiplicities after pion capture in181Ta and209Bi

The absorption of stoppedπ ^? in¹⁸¹Ta and²⁰⁹Bi has been investigated by studying prompt and delayedγ-ray spectra. Absolute cross-sections for the yield of isotopes per capturedπ ^? in (π ^?, xn) reactions, as well as the relative probability of populating nuclear states of different spins have been measured for the hafnium and lead isotopes, respectively. A spin as high as 20 has been observed in the production of²⁰⁴Pb. The ground-state rotational bands of the hafnium isotopes are excited to spin values up to 16. Neutron multiplicities as large as 15 have been observed for both targets. A neutron multiplicity of ?8 is most probable for both tantalum and bismuth targets. The strong interaction monopole energy shift? ₀ and widthΓ ⁰ for the 4f level are found to beε ₀(¹⁸¹Ta)=540±100eV; ?₀(²⁰⁹Bi)=1790±150 eV;Γ ₀(¹⁸¹Ta)=225±57 eV;Γ ₀(²⁰⁹Bi) =1166±70 eV. The quadrupole moments, determined from the hyperfine splitting of the 4f pionic atom level, areQ=3.30±0.06b andQ=}-0.50±0.08b for¹⁸¹Ta and²⁰⁹Bi, respectively.     

Measurement ofK-electron capture probability (P k ) in the decay of197Hg (64.1 h)

TheK-electron capture probability (P _K ) for the 268.7 and 77.3 keV states of¹⁹⁷Au in the decay of¹⁹⁷Hg (64.1h) have been determined from theKX-ray gamma ray summing in a HPGe X-ray detector. The measured values,P _k (268.7)=0.746±0.033 andP _k (77.3)=0.774±0.036 are found to be in good agreement with the theoretical results.