Proceedings of the Seminar on NJOY and THEMIS

Nuclear evaluated data processing codes are essential tools for the interpretation of basic data stored in files with formats reflecting the complex intrinsic structure of the data. They help users to filter out data and condense it to a form suitable to the physicist and engineer for nuclear application studies. The quality of evaluated data files can be determined by comparing their performance in predicting measured integral quantities. Evaluated data processing is an essential part in this benchmarking activity. Several tools have been developed over the years, but NJOY has taken up an eminent role because of its comprehensive set of features. NJOY and the French version THEMIS have been adopted as the standard processing codes for the JEF project. Considerable experience has been gained over the years from the different releases of NJOY and THEMIS. An important factor contributing to the improvements introduced has been the feedback provided by the users to the authors. The new format ENDF-6 adopted for the new evaluations led to a complete revision of NJOY which was recently released. It was therefore considered timely to organise a seminar in which the code developers and users could exchange information on: - the new features introduced in the most recent version - experience gained and validation of the different processing modules - maintenance, future developments and their co-ordination While a first workshop (1982) aimed at making NJOY known to the user community, the present seminar was aimed at experienced users. About thirty participants have attended the seminar and have contributed interesting presentations and lively discussions