Characterisation of the epithermal neutron irradiation facility at the Portuguese research reactor using MCNP

D G Beasley; A C Fernandes; J P Santos; A R Ramos; J G Marques; A King

doi:10.1016/j.apradiso.2015.03.005

Characterisation of the epithermal neutron irradiation facility at the Portuguese research reactor using MCNP

Appl Radiat Isot. 2015 May:99:186-92. doi: 10.1016/j.apradiso.2015.03.005. Epub 2015 Mar 4.

Authors

D G Beasley¹, A C Fernandes², J P Santos³, A R Ramos⁴, J G Marques⁴, A King²

Affiliations

¹ Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Potugal. Electronic address: d.beasley@ucl.ac.uk.
² Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Potugal.
³ Laboratório de Engenharia Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Portugal.
⁴ Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Potugal; Laboratório de Engenharia Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Portugal.

PMID: 25796059
DOI: 10.1016/j.apradiso.2015.03.005

Abstract

The radiation field at the epithermal beamline and irradiation chamber installed at the Portuguese Research Reactor (RPI) at the Campus Tecnológico e Nuclear of Instituto Superior Técnico was characterised in the context of Prompt Gamma Neutron Activation Analysis (PGNAA) applications. Radiographic films, activation foils and thermoluminescence dosimeters were used to measure the neutron fluence and photon dose rates in the irradiation chamber. A fixed-source MCNPX model of the beamline and chamber was developed and compared to measurements in the first step towards planning a new irradiation chamber. The high photon background from the reactor results in the saturation of the detector and the current facility configuration yields an intrinsic insensitivity to various elements of interest for PGNAA. These will be addressed in future developments.

Keywords: Analysis; Mcnp; Neutron beamline; Prompt gamma neutron activation; Research reactor.