This publication is the 3rd Special Issue of Nuclear Data Sheets dedicated to neutron cross section data. The 1st issue was published in December 2006 (Vol. 107, issue 12) and devoted to the new Evaluated Nuclear Data File, ENDF/B-VII.0, followed by the 2nd issue in December 2007 (Vol. 108, issue 12) dealing with neutron cross section evaluations. The success of our intention to publish papers with high impact can be illustrated by the very first paper of this series, the "big paper" on ENDF/B-VII.0, which in less than two years has exceeded 50 citations (Scopus). This year we are offering the readers a Special Issue on neutron cross section covariances, a hot topic in the nuclear data community.
The Workshop on Neutron Cross Section Covariances was held in Port Jefferson, a lovely little town located on Long Island in New York State, in early summer 2008. The Workshop, attended by 53 scientists (37 from the United States, 16 from 10 other countries), was held in response to considerable recent demand for extensive covariance information expressed by many user groups, such as advanced reactor systems, dosimetry and nuclear criticality safety to mention just a few.
The Workshop provided a forum for interaction between data producers and data users and addressed three main topics, namely, covariance evaluation methodology, recent covariance evaluations and users' perspective. It reviewed considerable progress achieved over the last few years in developing and consolidating evaluation methodology, with procedures depending on the incident neutron energy, type of nuclei and type of data. Several recent covariance efforts of a broader nature, such as low-fidelity project and major actinides in the US, as well as minor actinides in Japan, are already producing useful results. Users highlighted specific covariance data needs that require structured response, using methods varying from simple estimates to complex evaluations in accordance with assigned priorities and available funding.
These Proceedings contain 34 papers, arranged in the order as presented during the Workshop. The last paper in this issue is the Workshop Summary which offers comments on all presentations and posters including two oral presentations not published here and three posters merged with other papers.
I would like to express my sincere gratitude to all who made publishing of this issue possible, including the Workshop Organizing and Program Committee members, attendees, session chairs, discussion leaders, authors of the papers, Nuclear Data Sheets editorial staff as well as the staff of the Elsevier Publishing House. I owe special thanks to Boris Pritychenko for careful preparation and technical editorial work on this issue.