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1.
Changes of the radioactive decay rate of71Ge (T 1/2=11.43 days) have been studied experimentally for71Ge in some compounds of bivalent and quadrivalent germanium. Relative changes Δλ/λ of the electron capture probability have been measured, and the chemical changes Δρ(0) of the electron density at the germanium nuclei have been determined from these measurements. Values for the Mössbauer isomer shift calibration constants for the 67 keV γ-transition of73Ge have been estimated:C=δ/Δρ(0)=(0.061±0.020) mm·s?1/a.u., Δ〈r 2〉=(21±7)·10?3 fm2, ΔR/R=(6.9±2.3)·10?4.  相似文献   

2.
The weakβ ?-branchings in70Ga decay leading to excited states in70Ge at 1039 keV, and 1215 keV were measured byβ ?-ray and γ-ray detection in 4π geometry to be 0.36 ±0.02%, and 0.32±0.01%, respectively. The weak electron capture decay of70Ga was confirmed and its intensity measured to be 0.41±0.05%. The energy of the γ-rays was remeasured to be 176.17±0.02 keV, and 1039.20±0.08 keV.  相似文献   

3.
The decay of75Ga has been investigated with Ge(Li) spectrometers. Energy and intensity determinations for 37 gamma rays have been performed. A level scheme for75Ge was deduced, where 31 gamma transitions could be placed. Beta branch intensities were estimated from the measured gamma intensities. Spin and parity assignments for most of the levels were made in agreement with reaction and neutron capture studies. Half life of75Ga was measured to be (130±6) sec and that of the 139.3 keV isomeric state in75Ge to be (47.7±0.5) sec.  相似文献   

4.
Theγ-radiation following the β? decay of73Ga has been studied. Singlesγ andγγ coincidence spectra were recorded with Ge(Li)-detectors. 17γ-rays were assigned to transitions in73Ge, where 11 excited levels are proposed. From logft values based onγ-transition intensities, spin and parity assignments for the levels were deduced. The half-life of73Ga was measured to (4.86±0.03) h. From allowedβ-transitions the ground state of73Ga was assigned 3/2?.  相似文献   

5.
Primary capture gamma rays following multiple neutron capture in151Eu have been measured as a function of the irradiation time. Neutron capture cross sections of the152Eu 3? groundstate and of the152Eu 0? isomer (T 1/2=9.3h) were determined. These cross sections are relevant for the interpretation of inelastic scattering of neutrons at isomeric states with energy gain (neutron acceleration). The level scheme of153Eu has been extended. Neutron binding energies of152Eu,153Eu,153Gd and154Gd are given.  相似文献   

6.
7.
The time dependence of scintillation intensity from single crystals ofp-terphenyl and mixed crystals ofp-terphenyl and anthracene after bombarding with α-particles was investigated at the two temperaturesT=296 °K andT=92 °K. For the crystals ofp-terphenyl the time dependence of the scintillation anisotropy was also measured. Using the formulas given byKing andVoltz the decay curves ofp-terphenyl were decomposed into two components. Good agreement between experiment and theory was found. The ratio of the prompt intensity to the delayed intensity was determined to be 1∶2 atT=296 °K and 1∶3 atT=92 °K. The diffusion constants for triplet excitons were calculated to beD T(296 °K)≈10?5 cm2 sec?1 andD T(92 °K)≈ 2×10?6 cm2 sec?1, and the triplet-triplet interaction rate constantsχ tt(296 °K)≈ 2.5×10?11 cm3 sec?1 andχ tt(92 °K)≈0.5×10?11 cm3 sec?1.  相似文献   

8.
The low intensity β+/E.C. branches in the decay of45Ti to excited states of45Sc have been reinvestigated in order to resolve discrepancies in reported branching ratios. A new branch to the 974 keV level, having an intensity of 9.9±1.2×10?5/decay has been found. A previously reported branch to the 1237 keV level was found to be in error. The intensities for decay to the levels at 720, 1408 and 1661 keV levels were determined to be 154±12, 90.2±9.7 and 52.5±5.6, respectively, in units of 10?5 per decay.  相似文献   

9.
Ge–Sn compound is predicted to be a direct band gap semiconductor with a tunable band gap. However, the bulk synthesis of this material by conventional methods at ambient pressure is unsuccessful due to the poor solubility of Sn in Ge. We report the successful synthesis of Ge–Sn in a laser-heated diamond anvil cell (LHDAC) at ~7.6 GPa &; ~2000 K. In situ Raman spectroscopy of the sample showed, apart from the characteristic Raman modes of Ge TO (Г) and β-Sn TO (Г), two additional Raman modes at ~225 cm?1 (named Ge–Sn1) and ~133 cm?1 (named Ge–Sn2). When the sample was quenched, the Ge–Sn1 mode remained stable at ~215 cm?1, whereas the Ge–Sn2 mode had diminished in intensity. Comparing the Ge–Sn Raman mode at ~225 cm?1 with the one observed in thin film studies, we interpret that the observed phonon mode may be formed due to Sn-rich Ge–Sn system. The additional Raman mode seen at ~133 cm?1 suggested the formation of low symmetry phase under high P–T conditions. The results are compared with Ge–Si binary system.  相似文献   

10.
The decay of81As was investigated with Ge(Li) spectrometers. Accurate energy and intensity determinations for 29 gamma rays have been performed, from which a level scheme was deduced for81Se. Beta component intensities were obtained from the measured gamma intensities. Spin and parity assignments for most of the levels were made in agreement with the reaction and neutron capture studies. The half life of81As is measured to be (35.8±1.6) sec. Shell model calculations as well as unified model calculations have been performed in order to study the level scheme of81Se.  相似文献   

11.
A precision study of the decay of134Cs g and134Cs m has been made, using ordinary Ge(Li) spectrometers and ā Compton-suppression spectrometer. The logft value of the second forbidden nonuniqueβ-decay to134Xe has been measured to be 13.0±0.2. TheM4γ-ray transition in134Csm(8?) decay has been measured to haveα K= 73±7 and a hindrance of 7.0 over the Moskowski estimate. This is discussed in terms of the level configurations and the analogous transition in133Xe. A new intensity limit of 2×10?6 has been set for the zero-phonon transition between the 4+ and 2+ members of the two-phonon triplet. This leads to an upper limit forB(E2)4→2′, greater than 905. This and the more preciseγ-ray intensity values are discussed in relation to presently available nuclear models.  相似文献   

12.
B K Dasmahapatra 《Pramana》1975,4(5):218-221
The K-capture probability (P K) in the decay of139Ce (137.5d) has been determined from the analysis of the K x-ray gamma ray sum-peak observed with a Ge (Li) x-ray detector. Furthermore,P K is estimated independently from the measurement of the K x-ray intensity in the decay, using the known conversion coefficients of the 165.8 keV transition. Using the weighted average ofP K measured as above, the mass difference between139Ce and139La is found to be 273 ?13 +21 keV.  相似文献   

13.
The excited level scheme of189Os as populated by the decay of 23.4-h189Re has been studied by use of Ge(Li) and Si(Li) detectors in the γ-ray singles and coincidence mode. The data confirm the presence of excited levels in189Os at 30.8 (J π=9/2?), 36.2 (1/2?), 69.5 (5/2?), 95.2 (3/2?), 216.7 (7/2?), 219.4 (7/2?), 233.6 (3/2?), 275.8 (5/2?), 496.8 (1/2?, 3/2+) and 599.8 (1/2?, 3/2+) keV. The spin and parity assignments are based on multipolarities determined by internal conversion coefficient measurements and decay systematics. A decay scheme is established for189Re which accommodates 98% of the electromagnetic transition intensity. No evidence for the 150-d189Re isomer was found in this study.  相似文献   

14.
Gamma and beta rays from the decay of200Au (48.4 min) were studied employing Ge(Li) and plastic detectors in various singles and coincidence arrangements. The intensity of the β-branch to the ground state of200Hg was determined as 79%, and the disintegration energy of200Au to be asQ β=2.26 ± 0.06 MeV. A tentative spin and parity assignment of (1,2)+ is proposed for levels at 1515.2 and 1972.5 keV in 200Hg  相似文献   

15.
The decay characteristics of131I have been determined with high accuracy. The total branch from131I to131mXe has been measured to be 1.086±0.007%. The half life of131mXe has been measured as 11.770±0.012 days. Theγ-ray spectrum has been determined and new transitions at 85.92, 232.17, 295.83, 302.44, and 449.57 keV established. The position, spin and parity were established for a 9/2? level at 341.140 keV and spin and parity of 7/2? established for a level at 666.921 keV. The log f1t for the unique firstforbiddenβ transition from 7/2+ 131I to 11/2? 131mXe has been calculated to be 9.78.  相似文献   

16.
The decay of the174Tm activity has been studied with Ge(Li) detectors and with a Ge(Li)—NaI(Tl) coincidence arrangement. Gamma ray energies and relative intensities were determined. Five new gamma transitions are reported, four of which have been placed in the decay scheme in addition to the previously observed but unplaced 1305 keV transition. Five energy levels at 1557.7, 1762.1, 1781.1, 1877.5 and 2050.1 keV not earlier reported to be populated in the decay of174Tm are suggested. Some spin and parity assignments are proposed and the intrinsic structure of several states is discussed in terms of two quasi-particle excitations. For the half-life of174Tm a value 5.4±0.1 min was measured.  相似文献   

17.
The60Co decay has been reinvestigated using an electromagneticβ-spectrometer and a Ge(Li)γ-spectrometer. A new weakβ ?-transition of characterΔJ=3, no parity change between the 5+ groundstate of60Co and the second excited 2+ level atE=2.155 MeV in60Ni could be established. The endpoint energies and intensities of the threeβ ?-transitions are: $$\begin{gathered} E_{\beta \bar 1\max } = \left( {1.492 \pm 0.020} \right)MeV,I_{\beta \bar 1} = \left( {0.08 \pm 0.02} \right)\% ; \hfill \\ E_{\beta \bar 2\max } = \left( {0.670 \pm 0.020} \right)MeV,I_{\beta \bar 2} = \left( {0.18 \pm 0.03} \right)\% ; \hfill \\ E_{\beta \bar 3\max } = \left( {0.315 \pm 0.004} \right)MeV,I_{\beta \bar 3} = \left( {99.74 \pm 0.05} \right)\% ; \hfill \\ \end{gathered} $$ . The intensity ratio of the stopover and crossoverγ-transitions deexciting the 2.155 MeV level has been determined to be ≧120. Some conclusions for the theory are discussed.  相似文献   

18.
The level scheme of153Eu was investigated by observing the gamma-rays following theβ ?-decay of the 47 h153Sm using a high purity Ge(HPGe) detector and a Ge(Li)-Nal(Tl) fast-slow coincidence spectrometer. The energies and relative intensities of about fifty six gamma-ray transitions were determined. Five of them at energies of 124.91, 431.65, 443.24, 487.75 and 623.73 keV were observed and confirmed for the first time in the present singles and/or gamma-gamma coincidence measurements. These new transitions could be fitted into a proposed level scheme of153Eu. Theβ ?-decay branching ratios as well as the log (ft) values were obtained.  相似文献   

19.
The level scheme of75Se has been studied through the75As (p, n) reaction at proton energies from 1.5 to 5.0 MeV.γ-ray and internal conversion electron measurements were made using NaI (T1) and Ge(Li) detectors and a six-gap electron spectrometer. A proportional counter and a thin window NaI(T1) detector were used to detectγ-rays with energies less than 30 keV. The level scheme has been established by observing the thresholds of variousγ-rays and byγ-γ and e?-γ coincidence measurements. New levels at 133.0, 293.2, 790.0, 953.0, 1020.8, 1184.3, 1198.5 and 1258.2 keV not observed in earlier (p, n) studies have been established. Conversion coefficients of most of the low-lying transitions have been determined. Angular distributions of some of theγ-rays were also measured and compared with the statistical model calculations. DefiniteJ π assignments have been made to most of the low-lying levels. Life-times of the 112.1, 133.0, 286.7 and 293.2 keV levels have been measured to be 0.69±0.12, 5.3±0.6, 1.35±0.15 and 31±2 nsec respectively. The reduced transition probabilities for various low-lying transitions have been determined and compared with recent calculations. The 1/2? and 9/2+ levels hitherto unknown in this nucleus has been identified. The structure of the low-lying levels is discussed in terms of the existing models.  相似文献   

20.
The nuclear half-life of the 287 keV second excited state of75Se, populated by the reaction75As(p, n)75Se* has been measured by the delayed coincidence technique. NaJ(Tl)- and Ge(Li)-detectors were used for measuringγ-energies and time-spectra. By slope analysis of the time-spectra we obtained a half-life of T1/2(75Se, 287 keV)=(30.0±0.4) ns. Possible spin assignments for the 287 keV state in75Se from logft-values derived fromβ +-decay data of75Br to this level byBaskova et al are 3/2? and 1/2?. Application of an external magnetic field of 24 kG to the target nuclei yielded no measurable perturbation of the time-spectra, thus a spin value of 1/2? for this level seems to be more probable.  相似文献   

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