ATRON METROLOGY is helping to improve the theory explaining how collectrons work.
As part of a CEA thesis funded by the Nuclear Instrumentation project of the Gen2&3 programme, carried out in the IRESNE/DER/SPESI/LDCI laboratory (Laboratoire Dosimétrie, Capteurs et Instrumentation) at the Cadarache centre, and supervised by the LPC (Laboratoire de Physique Corpusculaire de Caen, UMR6534), tests on the ATRON electron beam were carried out with the aim of improving the theory explaining how collectrons work.
Collectrons (or Self-Powered Neutron Detectors, SPNDs) are neutron detectors used in nuclear reactors. They have a coaxial geometry with two metal electrodes (core and cladding) electrically insulated with a ceramic material (usually alumina, Al2O3), and produce an electric current proportional to the neutron flux to which they are subjected.
To explore the role of the insulator in more detail, Al2O3 samples positioned between two metal electrodes were irradiated in ATRON's irradiation chamber, LAETICIA, by electrons produced by the FELIX accelerator, with controlled incident energy (around one MeV) and intensity (of the order of µA). These measurements should provide a better understanding of the physical phenomena generated in the insulator, which are responsible for creating the DC current measured by a collectron when it is used in a reactor.