[en] The determination of the electron-capture efficiency αsub(s) for hydrocarbon-solute mixtures is discussed and the competition method is criticized because of the electron-transfer reaction between the two solutes. (author)

[en] The dependence of the free ion yield, Gsub(fi), on electrical field strength was determined in four liquid alkanes: n-hexane, 2,2-dimethyl butane, 2,2,4-trimethylpentane and 2,2-dimethylpropane irradiated by ⁶⁰Co γ rays at several temperatures. The sample purity effect on Gsub(fi) values has also been investigated. The Onsager theory applied to the experimental Gsub(fi) = f(E) curves allowed to estimate the distribution function F(r) of the initial separation distances r of ions in these alkanes. A modified exponential distribution seems to be the most suitable. The Jaffe theory to 2,2-dimethylpropane results permitted to determine the total ion yield value, Gsub(tot), for this liquid: Gsub(tot) = 4.3 +- 0.3

[en] A corrected curve of free ion yield versus electric field is given for n-hexane as well as new curves for 2-methylpentane, 2,2,4-trimethylpentane, and carbon tetrachloride. Comparison with the Onsager theory of geminate ion recombination does not give reasonable agreement over the entire range of field strengths for any of the functions used.(AIP)

No abstract available

No abstract available

[en] The first results obtained are presented on the determination of the ionisation potential of four alkanes (n-hexane, n-pentane, cyclopentane and trimethyl-2,2,4 pentane) in the liquid phase. In the gaseous phase, the ionisation potential values of these hydrocarbons are respectively 10.18 eV for n-hexane, 10.35 eV for n-pentane, 10.53 eV for cyclopentane and 9.86 eV for trimethyl-2,2,4 pentane. Consequently rare gas resonance lamps (krypton and Xenon) were made, sealed and excited by an ultra-high frequency wave, which emit photons in the energy field concerned, i.e. from 8.5 eV to 11eV. The energy of the photons emitted by these lamps is respectively 8.44 eV (100%) and 9.57 eV (2%) for xenon and 10.03 eV (100%) and 10.64 eV (5%) for krypton. From the extent of the induced ionisation currents and particularly the value of the ratio of the currents induced by the photons of the krypton and xenon lamps, a minimum value of the ionisation potential drop can be deduced compared with the gas phase of 0.61 eV for n-hexane, 0.78 eV for n-pentane, 0.96 eV for cyclopentane and a maximum value of 1.42 eV for trimethyl-2,2,4 pentane

[en] W values were determined by electric and radiochemical methods. Gsub(fi)=f(E) was determined for hexane (t=23 deg C, 0<=E<=160kV cm^-1), 2-methylpentane (t=25 deg C, 0<=E<=105kV cm^-1), 2,2,4-trimethylpentane (t=25 deg C, 0<=E<=140kV cm^-1) and carbone tetrachloride (t=23 deg C, 0<=E<=220kV cm^-1) irradiated by ⁶⁰Co photons. The radiochemical method consists in introducing a solute (C₆H₅Br) which reacts with the electrons emitted during the ionization of the solvent (C₆H₁₄). For hexane, the following values were found at 18 deg C: Gsub(gi)=4.0; Gsub(fi)=0.139; mean W=24.1eV

[en] In a 23-year-old woman CT demonstrated a patent giant intracranial aneurysm. MRI, CT and angiography one month later demonstrated complete spontaneous thrombosis of the aneurysm. The diagnosis was confirmed surgically and pathologically. This case demonstrates that a normal angiogram can be associated with a thrombosed giant aneurysm, and that this diagnosis should be considered in cases of angiographically-occult cerebral vascular malformations. (orig.)

[en] During the past few decades there has been an increase in the production of many types of electronic devices such as rectifying tubes, thyratrons, klystrons, magnetrons, etc., containing elements capable of emitting undesirable X-radiation. These components are not only found in equipment used in industry and research laboratories, but also in devices of a more domestic nature, such as colour television sets, usually low in energy, this radiation may nevertheless constitute a health hazard for many users of such devices and may affect not only workers but even the population as a whole. The Commission of the European Communities (Euratom) felt it was desirable to review the state of the art with regard to problems of radiological protection arising in the manufacture, repair and use of such electronic equipment and to seek suitable technical and administrative solutions. In conjunction with the Centre Physique Atomique et Nucleaire of the Paul Sabatier University, the Commission held an International Symposium in Toulouse on 3-6 November 1970, which was attended by manufacturers of electronic equipment, officials of technical inspection bodies and representatives of public health and occupational safety authorities. The following items were discussed: classification and identification of sources of parasitic X-rays, methods of measuring soft X-rays, biological aspects of exposure to soft X-rays, performance standards and methods for testing and inspecting electronic equipment. The Symposium was followed attentively by 180 delegates from 21 countries and international organizations, and was concluded by a round table discussion at which the chairmen of the different sessions, assisted by experts, drew conclusions from their sessions and from the discussions, pointing up the problems which needed most urgently to be studied. This document contains the texts, in their original versions, of the papers presented at the meetings, together with the minutes of the discussions and of the final round table meeting