Standard fields of old neutron sources--parameters and traceability.

Standard neutron fields of isotope neutron sources, established in the Institute of Atomic Energy, Poland, have been examined for nearly 20 y. The neutron dose equivalent and gamma dose rates were measured, applying various techniques. The neutron emission of standard neutron sources of 241Am-Be and 252Cf has been originally determined in primary standard laboratory, then checked, making use of transfer instrument calibrated in primary laboratory.