Historical
The idea to establish the k0-standardization, a method of neutron activation technique, came from three practical considerations made by Professor Frans De Corte while working on his PhD thesis. In short, his considerations intended to avoid:
1. the inconveniences caused by the use of elemental standards such as workload, unsuitability for survey analysis, loss of information in case of unexpected elements, and others;
2. the uncertainties and inaccuracies associated for instance with the introduction of absolute nuclear data when using the absolute (parametric) standardization - as developed by Girardi et al, 1964;
3. the inconvenience of the single-comparator standardization (k-method) developed by Girardi et al, 1965 - namely its inflexibility with respect to the irradiation and counting conditions.
In the late 60’s and early70’s, whereas Prof. De Corte was developing his studies on how to make the k-method flexible to the irradiation conditions, a team in Delft - De Bruin and Korthoven - was involved in making it flexible with respect to the counting conditions. And then, in 1975, Andras Simonits associated with De Corte to develop a flexible method for both irradiation and counting conditions. That is, to transfer from k (depending on irradiation and counting conditions) to k0 (independent of these conditions). But the k0 can also be considered an absolute method, where the uncertain absolute nuclear data are replaced by a compound nuclear constant, k0. Because of this, it was crucial to have accurate experimentally determined k0-factors. Simonits and De Corte decided to accomplish this in a long-term joint co-operation, with parallel but independent determinations in Gent’s (Belgium) and Budapest’s (Hungary) reactors so as to detect and avoid systematic errors. At the same time, they developed dedicated friendly-users protocols for the measurement of the irradiation and counting parameters (i.e. the calibration of the irradiation facility and the Ge-detector). Later on, other laboratories from all over the world joined this Gent-Budapest co-operation.
Once the k0-method was established, the idea of organizing a k0 Workshop was slowly growing. It was based on the obvious success and international spread of the method, and it was especially stimulated by the following facts:
1. at the Modern Trends in Activation Analysis - MTAA-7 Conference in Vienna, 1991, there were so many papers on k0 that Prof. Grass (the chairman) decided to insert a "Special Session k0";
2. a few colleagues, among them De Corte’s former PhD student Slobodan Jovanović, suggested and insisted on organizing of a meeting of k0 users, in order to evaluate the state-of-affairs, to exchange experiences, to discuss problems, to compare results, and to come to an outline of the future. Finally the first k0-workshop was organized. It was not called Workshop-I, because its organizers were not sure whether there would be a second one, but it turned out differently, and now Workshop-V (5th k0-Users Workshop) is being prepared.
The First k0 Workshop took place in Gent and the special detail about this meeting was that it was a real "Work"shop, where participants in before the audience gave live demonstrations of their softwares (on both mainframe and PC), with projection on a big screen. At that moment, it was an unprecedented fact in former international NAA meetings.
The success of the first workshop has led conducted to other workshops: the second was in Ljubljana, Slovenia, 1996, the third in Bruges, Belgium, 2001; the forth in Funchal, Madeira Island, Portugal, 2005. The fifth will be held in Belo Horizonte, 2009.
The method is still being intensively applied in spite of the fact that several research reactors were shut down interrupting the method application and studies carried out in the associated laboratories.
From 1992 on, more than 50 laboratories around the world established the k0-method and hundreds of papers have been published.
In Brazil, the method has been applied at CDTN/CNEN (Centro de Desenvolvimento da Tecnologia Nuclear/Comissão Nacional de Energia Nuclear) and at CENA (Centro de Energia Nuclear na Agricultura, Piracicaba, São Paulo).
