Gel dosimeters for dose imaging in high fluences of epithermal neutrons: Potentiality and limitations

Gel dosimeters with planar geometry (3 mm in thickness, many centimeters in diameter) have shown noticeable potentiality for dosimetry in phantoms exposed to the epithermal neutron beams of research reactors. In fact, it is possible to achieve images of the spatial distribution of the gamma dose, the neutron dose and the dose due to the charged particles generated by thermal neutron reactions. Such a dose separation is attained by means of measurements with gel dosimeters having suitable isotopic composition, and thanks to the planar geometry, the neutron transport in the phantom is not sensibly affected by the change in the gel matrix isotopic content. Moreover, the reliability of the results obtained utilizing these dosimeters with planar geometry for in-air measurements aimed at neutron beam characterization has been investigated. The obtained results show that gel dosimeters with suitable design can be a valid support for epithermal neutron beam dosimetry.