Development of unfolded fast neutron irradation positions at a 16.5 MeV GE PETtrace cyclotron and chronomorphic characterization of radiation damage on polyurethane

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The fast neutron energy flux spectrum was determined at a fluorine-18 ([subscript 18]F) producing cyclotron which is operated at the Missouri University Research Reactor (MURR) located in Columbia, Missouri. The Monte Carlo code MCNP6 was used to calculate the fast neutron flux which was experimentally validated based on neutron activation spectrometry measurements. Proton interaction calculations were based on the TENDL-2015 nuclear data library. The STAYSL PNNL Software Suite was used to determine a least-square spectral adjustment. Polyurethane samples were irradiated in the calibrated positions and dose dependent changes in the mechanical properties were analyzed via thermal mechanical analysis (TMA). The development of calibrated fast neutron irradiation positions at the MURR cyclotron is part of an effort of utilizing the routine PET (positron emission tomography) radiopharmaceutical production path in neutron irradiation chemistry studies.