1,723,335 research outputs found
Réalisation et mise au point d'un spectromètre compton Ge(Li)
No full textA single crystal Ge(Li) Compton spectrometer is described and has been tested.On décrit et on expérimente un spectromètre Compton utilisant un cristal unique Ge(Li)
Natural background in Ge(Li) spectrometers
No full textThe natural background activity of a Ge(Li) spectrometer was measured and background reduction was evaluated. Twenty lines were observed in the energy spectrum, extending from 20 to 1000 keV. Background reduction, achieved by shielding geometry improvements for low energy photon spectrometer, is presented. Continuum counting rate for 13% relative-efficiency Ge(Li) detector decreased from 4.9 c/min keV at 120 keV to less than 0.1 c/min keV at 900 keV in a 50 mm lead shield
Gamma-ray energies for calibration of Ge(Li) spectrometers
Full text linkGamma-ray energies are compared for bent-crystal measurements, Ge(Li) measurements, and other measurements. 150 gamma-ray energies below 3450 keV from 35 isotopes are being calibrated for calibration of Ge(Li) spectrometers. (WHK
Pegomya tenuiramula Ge, Li & Fan 1988
No full texttenuiramula Ge, Li & Fan in Fan et al., 1988b: 338 (Pegomya). Holotype male with labels: (1) printed with handwritten inscriptions on white label: “ Gansu Diebu / Chinese Academy of Sciences ”; (2) printed with handwritten inscriptions on white label: “19 79.IV.17 / collector Jianyi Wu and Xinmin Li”; (3) handwritten on white label: “ Pegomya tenuiramula ”; (4) printed with handwritten inscriptions on red label: “ TYPE / Pegomya / tenuiramula / Ge, Li et Fan ”. Preservation: pinned. Missing parts: left hind leg and all right legs. Paratype male with labels: (1) printed with handwritten inscriptions on white label: “ Gansu Diebu / Chinese Academy of Sciences ”; (2) printed with handwritten inscriptions on white label: “19 79.IV.17 / collector Jianyi Wu and Xinmin Li”; (3) handwritten on white label: “ Pegomya / tenuiramula / sp.n.”; (4) printed with handwritten inscriptions on red label: “ PARATYPE / Pegomya / tenuiramula / Ge, Li et Fan ”. Preservation: pinned; genitalia dissected and mounted on paper triangle, left wing and legs mounted on paper triangle. Current name: Pegomya tenuiramula Ge, Li & Fan, 1988.Published as part of ZHANG, XUFENG & ZHU, WEIBING, 2014, The types of Anthomyiidae (Diptera) in the Shanghai Entomological Museum, Chinese Academy of Science, China, pp. 1-67 in Zootaxa 3756 (1) on page 55, DOI: 10.11646/zootaxa.3756.1.1, http://zenodo.org/record/503313
Spectromètres Ge(Li) 0 absorption totale
No full textOn a réalisé divers spectromètres Ge(Li) à absorption totale constitués par deux diodes fonctionnant en coïncidence-somme, ainsi qu'un détecteur puits de 52 cm3
Ge(Li)-Ge(Li) coincidence measurements in 132Xe
No full textGamma-gamma coincidence measurements were carried out on the decay of 132I with two Ge(Li) detectors and a two parameter system. Several new transitions were observed. From these results, 18 new levels at 2 167.3, 2 187.4, 2 303.6, 2 916.9, 2 935.6, 2 959.1, 3 076.4, 3 112.1,3 122.3,3 155.4, 3 192.8, 3 214.3, 3 226.8, 3 237.4, 3 260.0, 3 319.6, 3 354.0, and 3 385.1 keV were placed in the 132Xe level scheme which incorporates 113 of the 119 definitely established gamma rays in this decay and can incorporate 5 of 16 additional tentatively reported transitions.On a effectué des mesures en coincidence gamma-gamma au cours de la désintégration de 132I avec deux détecteurs Ge(Li) et un système à deux paramètres. On a observé plusieurs nouvelles transitions. A partir de ces résultats, 18 nouveaux niveaux à 2 167,3, 2 187,4, 2 303,6, 2 916,9, 2 935,6, 2 959,1, 3 076,4, 3112,1, 3 122,3, 3 155,4, 3 192,8, 3 214,3, 3 226,8, 3 237,4, 3 260,0, 3 319,6, 3 354,0 et à 3 385,1 keV ont été placés dans le schéma des niveaux de 13 2Xe, ils comprennent 113 des 119 raies gamma définitivement établies et peuvent inclure 5 des 16 transitions supplémentaires qui ont été parfois avancées
Ge (Li) study of gamma rays from light xenon isotopes.
No full textThe introduction of Ge (Li) detectors for gamma rays allows a much better resolution than that obtainable previously with the scintillator-photomultiplier unit. Indeed the average loss of energy per ion pair in a Ge (Li) detector is about 2.4 eV, compared to the 130 eV required for one photoelectron in a scintillator-photomultiplier unit. [...
Time resolution of a Ge(Li) detector
No full textReports the measurements on the time resolution of an Ortec coaxial Ge(Li) detector of 7 mm depletion depth and 6 cm2 effective area in the energy range 32-1830 keV
Réalisation et mise au point d'un spectromètre compton Ge(Li)
No full textOn décrit et on expérimente un spectromètre Compton utilisant un cristal unique Ge(Li)
Large volume, multi-element Ge(Li) spectrometer.
No full textTo make use of the good energy resolution of Ge(Li) spectrometers of r-ray energies of several MeV, the sensitive volume must be increased to beyond 100 cm3. This volume is generally only attainable by operating several smaller spectrometers in parallel. Three coaxial Ge(Li) detectors were fabricated, assembled in a cryostat and operated in parallel. The spectral performance was relative efficiency of this multi-element spectrometer were investigated for r-rays of energies between 1 and 10 MeV. High energy r-rays (5-10 MeV) were obtained by thermalising neutrons from a Pu-Be source and then absorbing them in materials with high cross sections for radiative capture. The experience gained is summarised and alterations to future multi-element spectrometers are proposed
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