Characterization of the collimated output fluence , in a thermal neutron field, in terms of ambient equivalent dose H*(10,0)

The Brazilian Neutron Laboratory at the Institute of Radioprotection and Dosimetry (IRD) developed and built a new standard facility for thermal neutron flux, seeking to provide a new homogeneous fluence to calibrate neutron detectors and personal dosimeters. The purpose of this work is therefore to characterize the collimated output fluence, in a thermal neutron field, in terms of ambient equivalent dose H*(10,0) for calibration and irradiation of personal monitors and neutron survey meters.  The neutron fluence in the system irradiation field needs to be well known for personal monitors and neutron survey meters calibrated used in nuclear reactors in addition to studies and development of new materials for neutron dosimetry. The characterization of neutron thermal energy fields at the usual calibration points is one of the recommendations of the International Organization for Standardization ISO 8529, 2001 for international intercomparison of neutron fluence measurements. The determination of the ambient equivalent dose of the new facility was estimated based on a secondary transfer standard internationally known as Long Counter and properly characterized and traced back to the Neutron Laboratory primary standards.