[en] An EIC 1 extrapolation chamber, flushed with a methan based tissue equivalent gas is presented. This measuring device serves as a reference instrument to calibrate in tissue absorbed dose beta beams from different irradiation facilities; point radioactive sources, sources used with beam flattening filters, large area sources simulated by moving a point source. The source to detector distance has to be greater than 3 cm, requiring a transfer dosemeter for smaller distances. Influence of these different irradiation geometries has been studied on several radioprotection instruments (babyline, individual dosemeter, ionisation chamber), using three radionucleides: ¹⁴⁷Pm, ²⁰⁴Tl, ⁹⁰Sr + ⁹⁰Y

[en] At the beginning of the 1990s the restructuring of the industrial organization and the regulatory regimes are probably the most important economic and institutional phenomenon in electricity supply industries Latin America countries. This paper analyses the main characteristics of the restructuring in Chili and Brazil. Two major problems are driving this changes: the financial constraints and economic inefficiencies. Despite institutional barriers to privatization initiatives, the participation of new private companies in electricity supply industrial, specially in generation side, is becoming the common aspect of restructuring. This solution requires new regulatory options and new coordination mechanisms. In this context, the electricity companies may promote innovative strategies and adapt their long-term decisions. (authors). 2 tabs., 30 refs

[en] Desmodium incanum is a herbaceous legume native to Uruguay. Its perennial characteristics and good adaptability make this legumen interesting for animal nutrition and introduction in agricultural management practices. The research on native legume species well adapted to diverse ecological conditions,is an important subject for the agronomic potential that many species show. The objective of this work was to assess the nodulation status in the field and the nitrogen fixing capacity of rhizobial strains. This legume is well nodulated in the field and its nodulation is specific. None of the rhizobial strains isolated from other legume species (native o exotic)nodulated D.incanum.There were differences among the ecotypes studied in their symbiotic behaviour. 15 N methods permitted differentiation of the N-fixing capacity of rhizobial strains

[en] This report describes the experiment entitled 'Photophysics of Cyanine dyes on Surfaces'; carried out at the Central Laser Facility (CLF) from the 6th to the 20th January 1997. The experiment, funded by the Framework IV Large-Scale Facilities Access Scheme, was proposed by Prof. L.F. Vieira Ferreira, Centro de Quimica-Fisica Molecular, Complexo 1, IST, 1096 Lisboa Codex, Portugal, and carried out by visiting researchers from the Institute. They were supported by researchers from the Central Laser Facility, Rutherford Appleton Laboratory. Experimental results: The photo physics of 3,3'-Diethyloxadicarbocyanine iodide (DODCI) adsorbed onto swollen microcrystalline cellulose was investigated. Two fluorescence emissions band have been observed and assigned. One was due to singlet excited momers and a second new emission, seen at high laser fluences, was due to the formation of a photoisomer. The DODCI stays entrapped between the polymer chains and nonradiative pathways for deactivation are reduced, the lifetimes of the excited states were measured using time resolved fluorescence lifetimes techniques. The fluorescence lifetimes of the excited states are longer lived in a swollen cellulose matrix. The photoisomer emission especially lives an order of magnitude longer than in homogeneous media

[en] This report describes the experiment entitled 'Photoinduced absorption studies of the deactivation of excited electronic states in highly ordered films of oligothiophenes'; carried out at the Central Laser Facility (CLF) from the 15th February to the 5th March 1998. The experiment, funded by the Framework IV Large-Scale Facilities Access Scheme, was proposed by Dr. D. Oelkrug, Institute for Physical Chemistry, Germany and carried out by visiting researchers from the Institute. They were supported by researchers from the Central Laser Facility, Rutherford Appleton Laboratory. (author)

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No abstract available

[en] This paper presents in a summary form the topics covered in Topical Session 7. The following major topics were covered: Scope of comprehensive programme and practical implementation, including a graded approach to regulatory requirements; Licensing of cross-border situations; Quality assurance issues for regulators; Correct balance between enforcement and co-operation; Source inventory; Independence of regulatory bodies and how the need to develop a 'critical mass' of expertise may have an impact on this. There were 23 contributed papers from 20 countries submitted to this session, as follows: Nine papers from eight African Member States: Angola, Cameroon, Egypt, Kenya, Libyan Arab Jamahiriya, Nigeria, Sudan (two), Tunisia; Seven papers from six Asian Member States: Indonesia (two), Kazakhstan, Malaysia, Pakistan, Uzbekistan, Yemen; Five papers from four European Member States: Czech Republic (two), Estonia, Ireland, Russian Federation; Two papers from two Central American Member States: Cuba, Nicaragua. Since there are large differences in the amount and variety of radiation sources among individual countries and each of them has some specific features, a regional grouping of the submitted papers was selected in preparing the summary of the topics covered by this session

[en] The reason why there is no primordial antimatter in the Universe remains a mystery. Measurements with antimatter [1][2] show full compatibility with its matter counterparts at high precision and that the antimatter feels Earth's gravitational attraction similarly to matter [3] at low precision. Antihydrogen (Hbar) is produced by trapping antiprotons and positrons in neighboring wells in a Penning-Malmberg trap and slowing mixing then. An Ioffe-Pritchard octupole magnetic trap superposed to the Penning trap allows the trapping of the produced neutral Hbars with energy below 500 mK [4]. Since trapped antiprotons and positrons are needed to create Hbars, a bias magnetic field of ~1 T is used in the trap region. This high magnetic field adds some systematic uncertainties in comparing the two-photon 1s-2s transition in H and Hbar since accurate measurements with H [5] are performed in a very low magnetic field environment. The precision of the comparison can be improved by trapping hydrogen in the same Hbar trap [6][7][8] and repeating the exact measurements with both counterparts, avoiding many systematic uncertainties such as this magnetic field effect, AC Stark shift from the same laser and enhancement cavity operation [9]. However, the strong bias magnetic field still affects the transition's lineshape and center. It is possible to ramp down the bias magnetic field and perform the 1s-2s spectroscopy with Hbar's since we can always detect the annihilation of the ionized atoms efficiently. Nevertheless, repeating the exact measurement in a near-zero bias with H is not straightforward since we can not detect the annihilation. If we keep the bias magnetic field, it is possible to recapture a fraction of the ionized H during the spectroscopy [10] by using a weak Penning trap potential, but for a near-zero magnetic field, recapturing the protons can not be accomplished. Here, we suggest using a hybrid Penning-Linear-Paul trap, using a segmented electrode in the Penning-Malmberg trap to radially confine the ions to perform high precision 1s-2s spectroscopy in H in a near-zero field trap. We will discuss the stability of the recaptured particles in a Linear-Paul trap with a weak magnetic field along the axis, the effect of the electric field on the lifetime of the H/Hbar, lineshape of the transition, the effect of a superposed octupole field to the RF trap, patch potentials, and possible magnetic fields measurements at low fields. [1] - Borchert et al, Nature 601, 53-57 (2022). [2] - Ahmadi, M. et al., Nature557, 71-75 (2018) [3] - Anderson, E.K. et al., Nature 621, 716-722 (2023) [4] - Andresen, G. B. et al, Nature 468, 673-676 (2010) [5] - Parthey, C. G. et al., Phys. Rev. Lett.107, 203001 (2011) [6] - Azevedo, L.O.A. et al, Commun Phys 6, 112 (2023) [7] - S A Jones, New J. Phys. 24 023016 (2022) [8] - W. A. Bertsche et al 2022 J. Phys.: Conf. Ser. 2244 012080 [9] - ALPHA Collaboration, Nature Physics, Accepted - To be published [10] - Cesar, C. L., J. Phys. B49, 074001 (2016)

[en] Published in summary form only