International Workshop on the Avogadro Constant and the Representation of the Silicon Mole

Abstract

This special issue of Metrologia brings together contributions to the International Workshop on the Avogadro Constant and the Representation of the Silicon Mole, held in Turin, Italy, from 9 to 10 March 1994. It was organized by the Istituto di Metrologia "G Colonnetti" (IMGC) del Consiglio Nazionale delle Ricerche (CNR) and the Istituto di Fisica Generale "A Avogadro" (IFG) dell'Università di Tonno. It was sponsored by the CNR, the University of Turin, the Regione Piemonte, and the Commission of the European Communities – DG XII.The workshop was a follow-up to previous international meetings held in Turin to commemorate Amedeo Avogadro, one in 1911 (the centenary of the publication of his hypothesis) and another in 1957 (the centenary of his death). On this occasion the workshop was motivated by the requirements of researchers engaged in the international project on the determination of the Avogadro constant by the x-ray crystal density method. Sixty-four participants representing eight countries attended the workshop. Doctoral students in metrology from Turin University and researchers working in adjacent fields were also present. The lectures were chosen so as to review the different aspects of this project, to illustrate progress in research, and to indicate future developments to scientists working in different fields of physics, metrology and technology. Complementary approaches to the NA determination based on electrical measurements were also reported and analysed. During the workshop, a number of specialist meetings allowed experts to discuss specific topics, to exchange information on results and techniques, and to improve the coordination of their activities.In their opening addresses, Prof. C Castagnoli (Director of the IFG) and Prof. L Crovini (Director of the IMGC) welcomed the participants and introduced the work in progress with a view to making a more precise determination of the Avogadro constant. They mentioned the expected influence of this work on the set of consistent values of the fundamental physical constants and on the definition of the mass unit.Dr T Quinn, Director of the Bureau International des Poids et Mesures, chaired the final discussion, drawing attention to the message of the workshop and its contribution to mass metrology.Grateful thanks are addressed to all lecturers and participants and to the guest editors and reviewers of the papers for their contribution to the success of the workshop.