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[en] A study has been made of the effect on the efficiency and capacity of applying pulses of varying amplitude and frequency to a packed column. In the efficiency studies, the maximum efficiency was obtained with a pulse having an amplitude of 3/8'' and a frequency of 140 cycles per minute. Under these conditions, the column was about five times as efficient as a simple packed column. Two general types of results were obtained in the capacity studies. Under certain conditions, the capacity increased over that of a simple packed column, but under others, it decreased. Some of the factors causing this were investigated but the fundamental reasons were not determined due to a lack of personnel for the necessary experiments. (author)
[en] This article presents the Geiger-Muller counters which present the great benefit of being simple and steady in comparison with other known sensors. The authors propose an overview of problems related to the use of Geiger-Muller counters (GM counters). They first describe their operation (discharge initiation, discharge propagation, collection of positive ions and current in the counter). They discuss their limitations which are related to the migration delay of primary electrons and positive ions. They describe the operation circuit for counters with organic vapour, and for counters associated with counters using halogens. They address the main properties of GM counters, and the different factors to be taken into account when using them to count radioactive sources. The main types of GM counters are then described (they are used to measure different types of radiation). Measurement techniques are discussed for beta radiation (relationship between the number of disintegrations and the noticed counting rate, case of backscattering, absorption and diffusion in the counter window and in the air, influence of absorption and backscattering in the source), for alpha radiation, and for gamma radiation
[en] This Act provides for the setting up of an Atomic Energy Authority for the United Kingdom. It also makes provision for the Authority's composition, powers, duties, rights and liabilities, and may amend, as a consequence of the establishment of the Authority and in connection therewith, the Atomic Energy Act, 1946, the Radioactive Substances Act 1948 and other relevant enactments. (NEA)
[fr]La presente Loi prevoit la creation de l'Autorite de l'Energie Atomique du Royaume-Uni. Elle precise egalement la composition, les pouvoirs et les attributions de l'Autorite, et en raison de sa creation, modifie egalement la Loi de 1946 sur l'Energie atomique, la Loi de 1948 sur les substances radioactives et d'autres textes de lois concernes
[en] After some historic recalls, the different phases of discharge of a Geiger-Mueller counter is studied. It measures, by oscillograph method, the time between the flow of a particle through a determined area of the counter and the response of the associated amplifier. This time length is composed by the latency period and the delay itself which depends on the amplifier sensitivity. The selection of particles which generate a discharge in the studied counter is obtained with a two coincidence counters telescope in which the aperture is limited by four counters in anticoincidence with the first two counters. The measures have been done with different distance values and an overvoltage Vs which was applied to the counter. The dead time of a GM counter is also measured with a delayed coincidences method. The counter pulses which supply the coincidence circuit are delivered directly or with a known and variable delay. This method allows also to study the spurious pulses which are due to the positive ions impact on the counter cathode. Results for counters working in different conditions are given. It describes the system to limit the discharge which induces the increase of the life working of a counter, the decrease of its dead time and the reduction of the number of spurious pulses. In a second part, it describes the system to study the time correlation between different particles of the cosmic ray. An experiment concerning the presence of delayed particles in cosmic showers has permitted to specify the superior limit of this phenomena which is directly connected to the presence of heavy nuclear particles in the cosmic shower. (M.P.)
[en] The authors present a simple and very sensitive apparatus, and more particularly comments the results obtained in the study of paramagnetic resonance through the study of the absorption of high frequency waves by paramagnetic substances submitted to continuous magnetic fields, in the case of glass irradiated by γ rays or by neutrons. Reprint of a paper published in 'Comptes Rendus des Seances de l'Academie des Sciences', t. 238, sitting of Feb 1, 1954, p. 572-573.
[en] The existence of a 320 keV γ radiation in the decay of 105Rh has been confirmed. The partial β spectrum has been demonstrated by β-γ coincidence absorption measurements. Reprint of a paper published in 'Comptes Rendus des Seances de l'Academie des Sciences', t. 238, sitting of Mar 29, 1954, p. 1407-1409.
[fr]On a confirme l'existence d'un rayonnement γ de 320 keV dans la desintegration de 105Rh. Le spectre β partiel a ete mis en evidence par des mesures d'absorption en coincidences β-γ. Reproduction d'un article publie dans les 'Comptes Rendus des Seances de l'Academie des Sciences', t. 238, seance du 29 mars 1954, p. 1407-1409.
[en] An acetonic powder of the kidney of rabbit incubated at pH 7.3, under nitrogen, at 38 deg., in the presence of sulphur-labelled sulphite, pyruvic acid and glutamic acid leads to the enzymic formation of a labelled substance, which is shown by paper chromatography using various solvents and by paper ionophoresis at various pH's to behave like cysteine sulphinic acid. The performic oxidation of this substance yields a compound shown by paper chromatography to be identical to cysteic acid. The condensation of sulphite on an organic molecule has certain analogies with the fixation of CO2 by pyruvic acid, but its mechanism has not yet been elucidated. Reprint of a paper published in 'Biochimica et biophysica acta', Vol. 14, 1954, p. 415-420.
[fr]Une poudre acetonique de rein de lapin mise a incuber a pH 7.3, sous azote, et a 38 deg., en presence de sulfite marque au soufre, d'acide pyruvique et d'acide glutamique conduit a la formation enzymatique d'une substance marquee, qui se comporte par chromatographie sur papier dans divers solvants, par ionophorese sur papier a divers pH, comme l'acide cysteinesulfinique. L'oxydation performique de cette substance donne lieu a un compose identique par chromatographie sur papier a l'acide cysteique. La condensation du sulfite sur une molecule organique presente certaines analogies avec la fixation du CO2 sur l'acide pyruvique, mais son mecanisme intime n'a pas encore ete elucide. Reproduction d'un article publie dans Biochimica et biophysica acta, Vol. 14, 1954, p. 415-420.
[en] The adoption of a thermal neutron density calibration standard is proposed. The realisation of this standard is simple, cheap, reproducible with a better than 1.5% accuracy and provides a simple solution to the problem of various local calibration standards comparison. The density value of this standard, expressed using the absolute measurements previously carried out at Chatillon, is of (5,70 ± 0,19).10-3 n/cm3. Reprint of a paper published in 'Comptes rendus des seances de l'Academie des Sciences', T. 233, Sitting of June 21, 1954, p. 2413-2414.
[fr]On propose l'adoption d'un etalon de densite de neutrons thermiques de realisation aisee et peu couteuse, reproductible a mieux que 1,5 % et apportant une solution simple au probleme de la comparaison des divers etalons locaux. La valeur de cette densite, exprimee a l'aide des mesures absolues effectuees anterieurement a Chatillon, est de (5,70 ± 0,19).10-3 n/cm3. Reproduction d'un article publie dans Comptes rendus des seances de l'Academie des Sciences, T. 233, seance du 21 juin 1954, p. 2413-2414.
[en] Heavy water's superior moderating and neutron-economy characteristics give it an advantage over other moderators for use in natural uranium reactors. Despite its high cost, the use of heavy water is warranted because of the scarcity of enriched uranium and plutonium. Reprint of a paper published in 'Nucleonics', vol.11, no. 12, Dec 1953, p. 10-14.
[en] Activities of 2.7 h and 45 min periods of technetium 93 are analysed by isotope separation (mass number control), γscintillation spectroscopy, β spectroscopy, and β-γ and γ-γ coincidences. The positive β spectrum of 2.7 h period is made of two permitted spectra. Information is given about the molybdenum 93 excited states. Reprint of a paper published in 'Compte Rendus des Seances de l'Academie des Sciences', T. 238, Sitting of June 14, 1954, p. 2313-2316.
[fr]Les activites des periodes 2,7 h et 45 mn du technetium 93 sont etudiees par separation isotopique (controle du nombre de masse), spectrometrie γ par scintillation, spectrometrie β et coincidences β-γ et γ-γ. Le spectre β positif de periode 2,7 h est compose de deux spectres permis. Divers renseignements sont apportes sur les etats excites du molybdene 93. Reproduction d'un article publie dans les Compte Rendus des Seances de l'Academie des Sciences, T. 238, Seance du 14 juin 1954, p. 2313-2316.