[en] After the Chernobyl accident, the levels of ¹³¹I and ¹³⁷Cs were measured in surface air, pasture grass and milk produced by cows fed exclusively on fresh grass. The observed values of the vegetation-to-air, milk-to-vegetation and milk-to-air concentration ratios were compared with the values predicted by an internationally recognized assessment model for the transfer of radionuclides through terrestrial food chains. Predicted values were higher than the observed results by factors of 2.6, 2.1 and 5.6 for ¹³¹I and 4.3, 3.7 and 16 for ¹³⁷Cs, for the vegetation-to-air, milk-to-vegetation and milk-to-air ratios, respectively. A better agreement between prediction and observation was achieved by using experimental values of the following parameters; the mass interception factor (R/Y), the effective decay constants on vegetation (λ_ν) and the milk transfer coefficients (F_m), these being lower than the model default values. Milk produced by dairy cows fed on a mixed diet showed a different behaviour with regard to excretion of ¹³⁷Cs. (author)

[en] After a brief description of the Internet and the World Wide Web, we consider the applications to particle physics, the use of the 4. School Macintosh and the 4. School home page. A brief list of addresses and a glossary of technical terms are also given. (author)

[en] Poster presentation. 2 refs, 1 tab

[en] Recent experimental results obtained at high-energy accelerators are reviewed. The main emphasis is on collider experiments, at LEP and SLC for e⁺e^- collisions, Fermilab for p-bar p collisions, and HERA for ep collisions. (author)

[en] After the Chernobyl accident, samples of airborne material, fallout and soil were collected at Saluggia, Vercelli, northwest Italy. No significant differences were found in arrival times of the main radionuclides in air. Radioactivity in air was removed primarily by wet deposition rather than as dry fallout. For long-lived radionuclides ⁹⁰Sr and ¹³⁷Cs, activities deposited at Saluggia during May 1986 were 0.19 kBq m^-2 and 11.0 kBq m^-2 respectively, as measured in fallout samples. Reasonably good agreement was found between (a) ground deposition estimated from soil and fallout measurements and (b) measured values and those calculated from a deposition model. The greatest uncertainty lies in defining the distribution of iodine in air amongst particulate, elemental and organic phases and this affects the prediction of dry and wet contributions to total iodine deposition. (author)

[en] This paper describes the realization of a sampler for concentrating radionuclides from large volume of natural waters with the purpose to determine their concentration levels and their physico-chemical forms. Sample is pumped at a flow rate of about 0.5 m³/h through a set of sequential filters with different pore sizes to achieve separation of 'particulate' from 'dissolved' forms. Filtered samples is then passed through sequential beds of cation and anion exchange resins and activated alumina to obtain separation of dissolved forms on the basis of their charge. Ammonium Hexacianocobalt Ferrate (NCFC is used as a selective exchanger for Cesium isotopes. Filter and exchangers are measured by computerized gamma spectrometry. Detection limits are of a few tenths of Bq per cubic meter of sample. The main results obtained during radioecological surveys are also presented

[en] Concentrations of ¹³⁷Cs in water were monitored from 1987 to 1991 in the Dora Baltea river (northwest Italy), a river characterized by a catchment area located in a mountainous area which is largely covered with snow and ice in winter. A strong seasonal variation of water contamination was observed. Increased water concentrations in summer were attributed to caesium deposition and accumulation on snow-covered surfaces in winter and a delayed release in summer during ice and snow melting. An attempt to relate the observed cyclical variations with estimated transfer rates from the catchment has also been performed. (Author)

[en] This paper gives the results of individual monitoring carried out on population after Chernobyl accident. After a brief description of measurement methods as well as instrumentation features, the results of I-131 contamination in thyroid and of beta-gamma emitters on people's skin and clothing are reported. From the information available it appears that people coming out from Kiev (U.S.S.R.) showed the higher contamination

[en] A brief review is made of the present situation of hadron-hadron and hadron-nuclei total elastic and inelastic cross-sections at high energies

[en] The measurement of the gamma emitter radionuclides is quicker if direct field gamma spectrometry is used. The operations of setting and determination of the parameters necessary for the calculation of the results are described below. Furthermore, the good agreement between the results obtained by the direct measurement and those obtained by the sampling and the subsequent measurement in the laboratory, is show. (author)