Der Zerfall des84Rb und die Fluoreszenzausbeute von Krypton

The electron capture decay and the positron decay of⁸⁴Rb were investigated using NaJ (Tl)-detectors and a Ge (Li)-detector. Measurements of all intensities and of some informative double and triple coincidences were performed. From coincidence measurements betweenK-X-radiation and the following γ-radiation we got theK-fluorescence yield of Krypton Ω_itK=0.653 ± 0.004. Taking in consideration former measurements¹ one concludes a continuous behaviour of Ω_itK(Z) forZ=36, 37 and 38 within an uncertainty of 1%. For the branching ratios of the decay of⁸⁴Rb we obtained The half-life of⁸⁴Rb was determined to beT _1/2=(34.5 ± 0.2) d.     

Messung des gR-Faktors des 2+-Rotationsniveaus von Dy160 nach der Spinrotationsmethode und Bestimmung der Multipolmischungen mehrerer γ-Übergänge im Zerfall des Tb160

A differential measurement of the spin rotation of Dy¹⁶⁰ in the 2+ rotational state was performed by using liquid sources of TbCl₃ solved in 3M HCl and applying an external magnetic field of 33 500 Gauss. No change of the Larmor precession frequency could be detected within the first 10·10^?9 s. It is concluded that the ground state of the electronic shell of Dy⁺⁺⁺ is reached in 6·10^?10 s after theβ-decay of Tb¹⁶⁰. The valueg _R=+0.364±0.011 was derived using 〈r^?3〉_eff=8.92 a. u. for the 4f-shell of Dy⁺⁺⁺. A comparison with the result ofCohen who studied the Mössbauer-effect in Fe₂Dy shows that the value of 〈r^?3〉_eff must be 10% larger in this compound. A measurement of the effective magnetic field at the position of the nucleus in a source of terbium metal was performed for different temperatures. It revealed a temperature dependence which is very similar to the paramagnetic susceptibility χ(T). We observed a strong attenuation ofγ γ-angular correlations in the 2+ rotational state. For liquid sources of TbCl₃ solved in 3M HCl the following attenuation parameters were measured:

$$\begin{gathered} \lambda _2 = (0.122 \pm 0.013) \cdot 10^9 {\text{s}}^{ - {\text{1}}} , \hfill \\ \lambda _4 = (0.235 \pm 0.024) \cdot 10^9 {\text{s}}^{ - {\text{1}}} . \hfill \\ \end{gathered}$$     

Der Zerfall von Tm174 und Tm175

The radioactive isotopes Tm¹⁷⁴ and Tm¹⁷⁵ were produced by the reactions Yb¹⁷⁶ (γ, np) Tm¹⁷⁴ and Yb¹⁷⁶(γ,p) Tm¹⁷⁵ respectively, with bremsstrahlung of 54 MeV maximum energy. TheΒ- andγ-radiations from the decay of these isotopes were investigated using scintillation counters, solid state detectors and coincidence methods. The decay scheme proposed for Tm¹⁷⁴ is similar to those proposed by previous investigations. The spin assignment of the isomeric 1520 keV level was revised to beI=7. The decay of Tm¹⁷⁵, which was until now rather unknown, has a half-life of of 15.2±0.5 min. The suggested decay scheme shows excited levels at 105 (9/2^?), 511 (1/2^?), 553 (3/2^?), 598 (5/2^?), 643 (5/2^?, 7/2^?), 816 (3/2^?), 873, 990, 1454 (1/2⁺), 1496 (3/2⁺), 1505, 1810 and 1881 keV. The results are discussed using the Nilsson model.     

Der Zerfall des Pt195m und des Au195

The decays of Pt^195m (4.1 d) and Au¹⁹⁵ (192 d) have been investigated with a Ge(Li)-counter and a Ge(Li)-NaJ coincidence circuit. Theγ-spectrum of Pt^195m showed new lines with energies 239.5, 140.7 and 211.1 keV found earlier only in coulomb excitation experiments. Theγ-spectrum of Au¹⁹⁵ established a new level of Pt¹⁹⁵ at 199.8 keV with single particle character. These results led to a modified level scheme and modified reduced transition probabilities for the levels of Pt¹⁹⁵. By comparison of theγ-spectrum of Pt¹⁹⁵ m and Au¹⁹⁵ the ratios of electron capture branches of Au¹⁹⁵→Pt¹⁹⁵ decay have been determined.     

Der Zerfall von Er171 und Er165

Theγ-spectrum of a neutronactivated probe of natural Er₂O₃ revealed an additional peak at 55 keV, which was attributed to the characteristicK-Röntgenstrahlung from the decay of Er¹⁶⁵ by measurement of its half-life in a NaJ-wellcrystal. The activation cross section for thermal reactor neutrons for Er¹⁶⁴ (n, γ) Er¹⁶⁵ has been determined to σ _A =20±7 barn. The averaged conversion coefficient of the 111, 116 and 124 keV γ-rays from Er¹⁷¹→Tm¹⁷¹ have been remeasured with scintillation counter equipment.     

Zerfall des zweiten 2+-Zustandes von44Ca

Solid solutions between the compounds Nb₃Al, Nb₃Ga, Nb₃Ge, Nb₃In, and Nb₃Sn have been prepared by arc melting in argon atmosphere. Transitions to superconductivity, lattice constants and values of microhardness have been measured for all samples as cast as well as annealed. In agreement withMatthias et al. the highest transition to superconductivity at 20.05 °K has been observed in the system Nb₃(Al_1?xGe_x). A relation between microhardness and transition to superconductivity also expressed byMatthias has been verified for most of the systems.     

Der Zerfall des Fe53g und des Fe53m

Theγ-ray spectra from the decays of 8.5 min-Fe^53g and a new (2.51±0.02) min-Fe^53m have been investigated by means of Ge(Li)-detectors. As far as the Fe^53g -decay is concerned no other but the known 380 keV-transition (43%) has been observed indicating that the proceedingΒ ⁺-decay leads to the groundstate and first excited state of Mn⁵³ only. This contradicts formerΒ ⁺-spectroscopic results but is consistent with recent spin assignments. In the Fe^53m -decay fourγ-transitions have been found: 701 keV (100%), 1011 keV (76%), 1328 keV (76%), and 2339 keV (24%). The proposed level scheme of Fe⁵³: 0 keV (7/2^?), 1328 keV (9/2^?), 2339 keV (11/2^?), and 3040 keV (19/2^?, 2.5 min) is in agreement with results published recently byEskola. The level schemes of Mn⁵³ and Fe⁵³ are discussed in terms of the individual particle shell model.     

Die Art der Gamow-Teller-Wechselwirkung beim Zerfall von Li8

Zeitschrift für Physik A Hadrons and nuclei - Ziel dieser Arbeit war, aus der Elektron-Antineutrino-Winkelkorrelation beim Zerfall des Li8 eine Entscheidung darüber abzuleiten, ob beim...     

DasL/K-Einfangverhältnis von48Vanadium

We measured theL/K-capture ratio of⁴⁸V for all transitions simultaneously and foundP _L /P _K =0.104±0.004. Coincidence measurements with the γ-rays by scintillation counters led toP _L /P _K =0.115 ± 0.015. This latter value is not very exact, but the comparison of the number ofK-pulses in the two sets of measurements allows the statement that the⁴⁹V-impurity in the⁴⁸V was less than 1.1% at the time of delivery and less than 10% during the measurements. So a possible⁴⁹V-impurity did not disturb the results.     

Konversionskoeffizienten und Fluoreszenzausbeuten beim Zerfall des Hg199m

Hg^199m was produced by bombarding natural HgO with fast neutrons. The conversion electrons of the cascade decay were investigated with Si(Li)-counters. By application of the summing technique the conversion coefficients andL-shell fluorescence yields of Hg were determined. The gamma rays were studied with a Ge(Li)-counter. The following results were obtained: half-lifeT _1/2=(42.6± 0.2) min; energies of the transitionsE _γ1=(374.1± 0.1) keV,E _γ1=(158.3± 0.1)keV; intensity ratio of the gamma raysI _γ(158 keV):I _γ(374keV)=(424± 42):100; conversion coefficients α_K158=0.30± 0.03, α_total158=0.94± 0.09, α_K158/α_LM...158=0.47± 0.02, α_L158/α_M...158=3.10± 0.16;α_K374=3.51± 0.28,α_total1374=6.19±0.47,α_K374/α_LM...374=1.32±0.04, α_L374/α_M...374=2.14±0.11;L-shell fluorescence yields \(\bar \omega _L \) =0.40± 0.04, ω_KL=0.41±0.04.     

Diekll-Auger-Spektren von Eisen und Vanadium

The relative intensities of theKLL-Auger transitions of Fe (Z=26) und V (Z=23) were measured with an iron free, double focusing β-spectrometer. The results obtained are in good agreement with those measured bySokolowski andNordling forZ=29 andZ=32. This confirms the discrepancies between the nonrelativistically calculated intensities and the experimental values in the region of lowerZ. A summary is given about all known measurements of theKLL-Auger intensities. Also theKLL∶KLX-ratio of Fe was measured to be 1·0∶(0·19±0·01). The energy of the 14·4-keVγ-transition of Fe⁵⁷ was evaluated to be (14389±6) eV.     

Der Zerfall des Ag106g und Ag106m

The decays of the 25 min-Ag^106g and 8.3 d-Ag^106m have been investigated using Ge(Li)- and Si(Li)-counters. Theγ-rays of 17 transitions in the Ag^106g -decay and of 42 transitions in the Ag^106m -decay have been observed and their energies and relative intensities have been determined. The intensities of theseγ-rays and the intensities of conversion-electrons known from earlier measurements allow the determination ofK-conversion-coefficients for 23 transitions. The present data are consistent with a level-scheme of Pd¹⁰⁶ having states at 0, 0⁺; 511.8, 2⁺; 1127.8, 2⁺; 1133.1, 0⁺; 1228.8, 4⁺; 1557.4, 3⁺; 1562, 2⁺; 1702.8, 4⁺; 1931.7, 3, 4⁺; 2002, 0⁺; 2040.4, 3, 4⁺; 2076.8, 3, 4⁺; 2084.2, 3^?; 2305.7, 4^?; 2324, 1, 2⁺; 2350.4, 3, 4⁺; 2365.3, 3, 4⁺; 2529, 1, 2⁺; 2756.3, 5⁺; 2951.3 keV, 5⁺. The level-scheme of Pd¹⁰⁶ is compared with the predictions of the vibrational model for spherical nuclei.     

Konversionskoeffizienten und Fluoreszenzausbeuten beim Zerfall des Ir192m und Co58m

With a proportionalcounter and an anthracene-crystal-spectrometer theL-X-ray- and the conversion-electron-spectra of \(Ir^{192_{m_1 } } \) were measured. TheL-fluorescenceyield of iridium was found to beω _L=0.30±0.04. The partial fluorescence-yields of theL ₂- andL ₃-subshells could be determined:ω _L2 =0.35±0.14 andω _L3 =0.29±0.04. The conversion-coefficients for the isomeric transition of \(Ir^{192_{m_1 } } \) were also measured:α _L =1660±250 andα _L +α _M =2030±230. The spectra of the conversion-electrons of the 25 keV-isomeric transition of \(Co^{58_m } \) were measured with a methane-filled proportionalcounter, and theγ- and X-rays with a Nal-scintillation-spectrometer. The conversion-coefficients for this transition and theK-fluorescence-yield of cobalt were found to beα _K =2000±260,α _L+M =890±150,K/(L+M)=2.25±0.15,α _K =0.34±0.02.     

Zum Zerfall von Tc96g und Tc96m

Theγ spectra of Tc^96g (103 h) and Tc^96m (51.5 min) have been investigated using Ge(Li) detectors. In the decay of Tc^96m γ transitions of 480, 720, 779, 851, 1094, 1201 and 1499 keV have been identified. These results are only compatible with spin and parity 7⁺ and 4⁺ for Tc^96g and Tc^96m respectively,γ-γ coincidence measurements yielded a revised level scheme of Mo⁹⁶.     

Untersuchung der bisher Ir198 zugeschriebenen 50 sec-Aktivität und Neuzuordnung zum Zerfall von Ir196

Theγ-spectrum of Pt¹⁹¹ has been measured with a Ge(Li)-counter. In addition to earlier measurements about 20 newγ-rays have been found, 10 of them were known as conversion-lines in earlier investigations. The intensities of these conversion-lines and the estimatedγ-ray-intensities allowed the determination of conversion-coefficients. A new level-scheme with 5 new levels at 569, 602, 660, 865 and 940 keV is proposed.     

Der Zerfall des Au195m,des Hg195m und des Hg195

Theγ-radiation of Au^195m , Hg^195m and Hg¹⁹⁵ was measured with a Ge(Li)-semiconductor detector. Conversion coefficients of most transitions could be determined from the measuredγ-intensities and from already known electron intensities. Spin and parity of the corresponding niveaus and logft-values for the decay of Hg¹⁹⁵ and Hg^195m were determined. Newγ-energies (698 keV, 754 keV, 852 keV) were found in the decay of Hg^195m . With a coincidence method a value of α_tot=13±3 for the 61,5 keV-radiation of Au^195m was measured.     

Der Zerfall des Co60m und Zr90m

Co^60m was produced by the reaction Co⁵⁹ (n,γ) Co^60m ; its decay has been investigated by scintillation spectrometers. The half-period has been remeasured yielding a value ofT _1/2=(10·35 ±0·20) min. The isomeric decay mainly leads to the Co⁶⁰ ground state by a (58·6±0·6) keV transition. TheK-conversion coefficientα _K= 41±3 and the total conversion coefficientα=47±3 indicate the transition to beM3 and the spin of Co^60m to be 2⁺. Further Co^60m decays by beta transitions to Ni⁶⁰. The beta component (8·6±1·2)·10^?3%, log ft=7·32 leading to a (2·16±0·02) MeV level has been measured for the first time. A second component (0·24±0·03)%, log ft=7·23 leads to the 1·33 MeV level. The 2·16 MeV level decays to the Ni⁶⁰ ground state mainly by a 0·83–1·33 MeV cascade, in a few cases by a direct transition. The spin of the 2·16 MeV level is 2⁺. Zr^90m was produced by the reaction Zr⁹⁰ (n,n′) Zr^90m . The half-period was measured yielding a value ofT _1/2=(0·83±0·03) sec. Zr^90m decays in the following way: (77±5) % by a direct (2·31±0·02) MeV —E 5 transition to the Zr ground state and (23±5)% by a (132·5±1·5) keV-(2·18±0·03) MeV cascade detected for the first time in the isomeric decay. TheK-conversion coefficient of the 132·5 keV transition isα _k=(2·2±0·3) indicating this transition to beE3 and the spin of the 2·18 MeV level to be 2⁺. The Zr^90m -decay sheme is in accordance with the level sequence of Zr⁹⁰ as measured in the Nb⁹⁰ decay.     

Der Zerfall des125m Xe,des127m Xe und des127g Xe

The decay of^125m Xe produced by the reaction¹²²Te(α, n)^125m Xe using a target enriched in¹²²Te (95.4%) and the decay of^127m Xe produced by the reaction¹²⁷J(d, 2n)^127m Xe have been investigated: ^125m Xe decays with a half-life ofT _1/2=(56±3) sec by ayy- cascade withE _γ1=(140.4 ±0.5) keV andE _γ2=(110.5 ±0.5) keV. The experimental conversion coefficients yield multipolarities ofE3 for the 140.4 keV isomeric transition and predominantlyM1 for the 110.5 keV-transition. ^127m Xe decays with a half-life ofT _1/2=(71±2) sec. The decay also proceeds by aγγ-cascade with an isomeric E3 transition ofE _γ1=(172.5±0.3) keV and a predominantlyM1 transition ofE _γ2=(124.6±0.3) keV. In the decay of^127g Xe an additional branching of the electron capture to a level at (618.1±0.3) keV was observed. The relative probability forK-captureP _K618/P_K375=0.40 ±0.07 yields a total transition energyQ _EC=(664 ±4)keV. A spin of 1/2⁺ was assigned to the ground state.