ACTA

Study and Characterization of LiF Thin Film Combined with a Silicon Detector for Neutron Metrology

H. Brahimi^a, A. Keffous^b, N. Haine^c, B. Rahal^a, Y. Larbah^a
^aNuclear Research Center of Algiers, 02, Boulevard Frantz Fanon, BP 399, 16038, Algiers, Algeria
^bResearch Center in Semiconductors Technology for Energy (CRTSE), 02, Bd. Dr. Frantz Fanon, B.P. 140, 7 Merveilles, 16038, Algiers, Algeria
^cFaculty of Physics, University of Sciences and Technology - Houari Boumedienne (USTHB), BP 32, Bab Ezzouar, 16111, Algiers, Algeria

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The last decades have seen a lot of work and development on new methods of neutron detection that would replace ³He gas-based detectors, a device widely used due to its efficiency, which is being phased out due to the scarcity of ³He gas and its high cost. The work showed that a combination of inorganic materials (Si, ⁶LiF) could represent a viable basis for the development of new generations of thermal neutron detectors. This type of device is based on a silicon detector coupled to ⁶LiF thin film converters. In this work, a model has been developed based on the fabricated silicon detector with a Schottky surface barrier associated with different thicknesses of ⁶LiF films. To study its behavior as a function of the different film thicknesses, the model was characterized using a thermal neutron flux from the source (AmBe-OB26). Preliminary results show that it is possible to measure low-energy neutrons with an average detection efficiency of about 1%, a sensibility of 10±0.1 cps on the ³H peak, and insensibility to gamma radiation <10^-6, with a thin films size of about 2 μm. In this paper, we will present a state of the art of detector design, an evaluation of its characteristics (efficiency, resolution, dead time, proper motion), and a clarification of the influence of other parameters on the shape of the spectrum, highlighting the possibility of improving its detection efficiency to make it high, with a gamma/neutron rejection capability comparable to the ³He gas detector.

DOI:10.12693/APhysPolA.143.400
topics: ⁶LiF, silicon, neutron, detection