Thermal neutron conversion by high purity 10B-enriched layers: PLD-growth, thickness-dependence and neutron-detection performances

Abstract

Neutron applications and detection are of paramount importance in industry, medicine, scientific research, homeland security, production of extreme UV optics and so on. Neutron detection requires a converter element that, as a result of its interaction with neutrons, produces reaction products (mainly charged particles) whose detection can be correlated with the neutron flux. Reduced availability and increased cost of the most used converter element, 3He, have triggered research efforts for alternative materials, proper deposition methods and new detector architectures. 10B converter is a valid alternative to 3He thanks to its high thermal neutron cross section and relatively high Q value. In this paper we report on the room temperature Pulsed Laser Deposition (PLD) of high quality and uniform 10B films with the expected density, different thickness values (0.5, 1.0, 1.2, 1.5 and 2.0 μm) and uniform thickness over a circular area of about 30 mm in diameter. Additionally, they are adherent to the substrate with a negligible presence of contaminants. The conversion properties of such 10B coatings coupled to a Si solid state detector are studied upon exposure to a neutron flux from an Am-Be neutron source (2.2·106 n/s). The experimental results, compared with spectra simulated by using a GEANT4 code, present a good agreement and efficiencies of the order of a few percent.

Study of a metal-halide perovskite CsPbBr3 thin film deposited on a 10B layer for neutron detection

“…The film was coupled with a Silicon solid-state detector and exposed to a neutron flux emitted by an Am-Be neutron source at a rate of 2.2 × 10 6 s −1 . The results from both experimental measurements and simulations conducted using the GEANT4 toolkit showed excellent agreement, indicating a neutron detection efficiency of approximately 2% [35].…”

“…The process resulted in a uniform 10 B film with a thickness of 1 µm on the On top of this 10 B film, a 1 µm layer of CsPbBr 3 perovskite was deposited. In previous research [35], the compositional, structural, and morphological characterization of the 10 B film has already been conducted. In the present work, a comprehensive characterization of the perovskite film is performed using RBS spectroscopy, SEM, and XRD techniques.…”

“…The morphology and structure of the film were also studied using SEM (Scanning Electron Microscopy), and XRD (x-ray Diffraction Spectroscopy) analysis. As an outcome, the film exhibits a macroscopically uniform behavior, free of flaws that could induce delamination and cracking, compromising its adhesion to the substrate [35].…”

“…On the other hand, the detection of thermal neutrons (energy <0.5 eV; cadmium cut-off energy) plays a crucial role in various fields, including high-energy physics studies, fission and fusion research, nuclear power plants, homeland security, neutron imaging, large scientific research facilities, and nuclear medicine, among others [14,[25][26][27][28][29][30][31]. Neutron detection methods are generally based on the detection of secondary charged particles produced by the neutron capture reaction by 'conversion' elements, like 3 He [32,33], 6 Li [34], and 10 B [35], characterized by high cross-section for thermal neutron capture and high Q values [36]. In the nuclear reaction using 10 B as conversion material (cross-section for thermal neutron capture reaction is 3840 barn [37]) two charged particles, one 7 Li ion, and one α particle, are produced (see figure 1).…”

The Gamma and Neutron Sensor System for Rapid Dose Rate Mapping in the CLEANDEM Project

“…157 Gd ≈254,000 too many gammas (and toxic) [26,27] 113 Cd ≈20,000 too many gammas (and toxic) [28,29] 3 He 5333 expensive, being replaced in neutron detection applications, non-natural, produced in military reactors [30] 10 B 3837 expensive, produces low energy alpha and 7 Li particles but also gamma rays [31][32][33] 6 Li 940 cheaper, easily deposited ( 6 LiF), produces high-energy triton and alpha particles and no gamma rays [33,34] 235 U ≈583 dangerous strategic material, radioactive, subject to radiation protection restrictions [33] According to the long standing SiLiF technique [20][21][22][23][24][25], a 6 LiF layer of 4300 µg/cm 2 areal density (≈17 µm thickness at nominal density), enriched at 95% in 6 Li, was deposited onto a glass substrate by means of a reasonably simple chemical procedure [34]. As for the silicon diode, an off-the-shelf PIN photodiode of 1 cm 2 area and 300 µm thickness was chosen, namely the unsealed S3590-09 [35] produced by Hamamatsu Photonics, Hamamatsu, Japan, costing about EUR 100, which has no transparent resin window in front, so that the particles can reach the depleted junction region.…”