Neutron measurements by passive methods in the Dubna transmutation assemblies

In the general case of neutron measurement by passive detectors, the conversion of direct experimental data to neutron flux results by using (1) a cross-section of the reaction on which the detector is responding or (2) an appropriate calibration of the detector versus neutron energy. For a better estimation of the neutron flux, especially in real neutron fields, the calculation of the effective cross-section in the first case and the calculation of an effective conversion factor from Tracks to Neutrons (TN) in the second case, both corresponding to the neutron energy spectrum, is required. This work is an application on the determination and comparison of neutron fluxes in the experimental transmutation assemblies in Dubna using several types of passive detectors. For the calculation of the effective cross-sections as well as of the effective conversion factor TN for each experimental assembly the neutron energy spectral shape was estimated theoretically by using the high-energy transport code DCM-DEM.