[en] Two coaxial Ge(Li) spectrometers A and B with respective relative efficiencies of 5.4 and 22.3% with FWHM better than 2.5 keV have been used in a detailed study of background spectrum in the energy range from 0.03 to 80 MeV. The lead castle (effective thickness 15 cm) was originally constructed for a smaller spectrometer (A), its integral background count rate for energies above 30 keV amounts: N(>30 keV)=0.88+-0.01 cps, which allows to measure specific activities (concentrations) of 7 Bq/kg. This shielding is not good enough for the larger detector (B,N>2 cps) but due to its high peak to compton ratio (46:1) it allows to determine even lower specific activities (1 Bq/kg). Detector B has been used to detect ¹¹³Cd(n,γ)¹¹⁴Cd and H(n,γ)D reactions induced with ''natural neutrons'' through the observation of 558.7 and 2223.7 keV gamma lines. The line at 558.7 keV will be recommended to settle the criterion for ''line observability'' in the background spectrum of a shielded detector. Both detectors have been used to measure μ-mesonic dEsub(μ)/dx spectrum. (author)

No abstract available

[en] We suggest that radioactive food contamination, as determined solely by a quantitative gamma-ray spectroscopic measurement, may, apart from the total activity per unit mass, be for quick reference conveniently characterized by another single figure which we call the ''Gamma Contamination Food Factor'' (GCFF). This factor may be defined as the ratio of the total specific activity of gamma-ray-emitting radionuclides in the food sample (except that of ⁴⁰K) to the specific activity of ⁴⁰K either in the sample itself or in an ''average man''. We discuss briefly the meaning and advantages of these definitions. (author)

[en] It has been shown that dominant ²²⁷Ac impurity in some non highly purified lanthanum compounds as La(NO₃)₃x6H₂O or La₂O₃, together with its daughters, can be used for efficiency calibration of Ge-detectors in the energy range from 50 keV to 1500 keV, using ¹³⁸La to determine the ²²⁷Ac activity. These compounds are recommended for the calibration of voluminous liquid and powdery samples. (orig.)

[en] The problem of maintaining a low-level spectrometer free of contamination under conditions of high environmental contamination is of significant concern to monitoring laboratories. A chance to test the procedures for protecting our HP-Ge detector arose during the first stages of the Chernobyl incident. The background gamma-ray spectra of the 8% efficiency shielded low-background HP-Ge detector in the energy range of 60-2,700 keV before and after the Chernobyl accident had been investigated. In the measurement performed just the day before a radioactive cloud reached the area, the total count rate in that energy range was found to be 0.58 c.p.s. The highest rates between 0.8 and 0.9 c.p.s. were obtained 4-7 days after the accident. In the measurement from about 70 days after the accident, the rate was 0.59 c.p.s. (i.e., very close to the rate value before the accident). The presence of some 14-15 fission products have been confirmed in measurements of gamma spectra of samples taken from outside the laboratory, shortly after a radioactive cloud spread all over the country. In the background spectrum taken 70 days later, only gamma lines of three isotopes remained: ¹⁰³Ru(39.2d), ¹³⁴Cs(2.06y), and ¹³⁷Cs(30.14y). 1 ref., 1 fig. 1 tab

[en] Abstract only. 3 refs

[en] Low-background off-line gamma-ray spectroscopic measurements of the thin Au and thick Ta targets have been performed to determine or estimate yields of long-lived isotopes created in the following reactions: ⁷⁴Ge + ¹⁹⁷Au and ⁹³Nb + ¹⁸¹Ta. The main goal of these experiments was to investigate and compare mechanisms dominating the reactions in the two similar compound systems for a thin and thick target at approximately the same incident energy of 18 meV/u. The cumulative cross-section distribution for the formation of proton-rich, neutron-rich chains and independent isotopes in 495 μg/cm² thick Au target after bombardment with ⁷⁴Ge ions, has been determined for about 90 (T_1/2>1.5 d) nuclei. The similar cumulative cross-section distribution of about 50 (T_1/2>20 d) reaction products in 0.5 mm thick natural Ta target after bombardment with ⁹³Nb, has been determined and compared with the former one. (author)

[en] Seventeen honey samples collected at different sites during 1992 have been measured using the method of γ-spectroscopy. Measurements were performed by a low background high purity germanium spectrometer of a relative efficiency of 14.5% and an energy resolution of 1.7.keV. Using natural γ-ray sources to determine efficiency, it has been shown that out of 17 samples of natural honey only two (of meadow type) have specific activity of ¹³⁷Cs greater than 0.5 Bq kg^-1. The remaining samples have the same ¹³⁷Cs concentrations as before May, 1986. Predominant activity in all samples comes from the ⁴⁰K radionuclide, indicating natural honey. (author) 5 refs.; 1 tab

[en] We propose two reactions induced by environmental gamma-rays which may eventually have the same input and output nuclear channels as the neutrino capture itself and whose yields therefore must be estimated in background evaluation. From here there follows the need to know the gamma-ray spectra at the excavation site. (orig.)

[en] The main goal of this work is to establish the nuclear decay scheme of ⁷⁶Sr and energy levels of its doubly odd daughter nucleus ⁷⁶Rb. The extremely neutron deficient nucleus ⁷⁶Sr lying at the N=Z (=38) line with half-life of 8.9 s was produced in spallation reactions of 600 MeV protons from the CERN Synchrocyclotron (SC) with a Nb multifoil target in conjunction with a W surface ionization source at the ISOLDE facility. The γ-spectroscopy measurements have been performed with two Ge detectors which were positioned at about ±30 degree respectively downstream to the ⁷⁶Sr beam. The obtained singles and coincidence γ spectra were used to determine energies and intensities of γ lines assigned to the decay of ⁷⁶Sr and to establish some details of the nuclear level configuration of its daughter nucleus ⁷⁶Rb up to 1000 keV