Neutron cross section standards are important in the measurement and evaluation of all other neutron reaction cross sections. Not many cross sections can be defined as absolute - most are measured relative to the cross section standards. The most recent evaluations were completed in 2005 and a report was published in 2007 (STI/PUB/1291). Further information can be found in Nuclear Data Sheets Volume 110, Issue 12, December 2009, Pages 3215-3324.