Thermodynamics kinetics of boron carbide under gamma irradiation dose

In this paper, high purity boron carbide samples were irradiated by [Formula: see text]Co gamma radioisotope source (0.27 Gy/s dose rate) with 50, 100, 150 and 200 irradiation hours at room-temperature. The unirradiated and irradiated boron carbide samples were heated from 30[Formula: see text]C to 1000[Formula: see text]C at a heating rate of 5[Formula: see text]C/min under the argon gas atmosphere of flow rate 20 ml/min. Thermogravimetric (TG) and Differential Scanning Calorimetry (DSC) were carried out in order to understand the thermodynamic kinetics of boron carbide samples. The weight kinetics, activation energy and specific heat capacity of the unirradiated and irradiated boron carbide samples were examined in two parts, T [Formula: see text] 650[Formula: see text]C and T [Formula: see text] 650[Formula: see text]C, according to the temperature. The dynamic of quantitative changes in both ranges is different depending on the irradiation time. While the phase transition of unirradiated boron carbide samples occurs at 902[Formula: see text]C, this value shifts upto 940[Formula: see text]C in irradiated samples depending on the irradiation time. The activation energy of the unirradiated boron carbide samples decreased from 214 to 46 J/mol in the result of 200[Formula: see text]h gamma irradiation. The reduction of the activation energy after the irradiation compared to the initial state shows that the dielectric properties of the irradiated boron carbide samples have been improved. After the gamma irradiation, two energy barrier states depending on the absorption dose of samples were formed in the irradiated samples. The first and second energy barriers occurred in 0.56–0.80 and 0.23–0.36 eV energy intervals, respectively. The existence of two energy levels in the irradiated boron carbide indicates that the point defects are at deep levels, close to the valence band.

[1]  S. Jabarov,et al.  Formation of Color Centers and Concentration of Defects in Boron Carbide Irradiated at Low Gamma Radiation Doses , 2019, Journal of the Korean Physical Society.

[2]  S. Jabarov,et al.  Calculation of the Thermal Parameters of Boron Silicide by Differential Scanning Calorimetry , 2018, Physics of Particles and Nuclei Letters.

[3]  S. Jabarov,et al.  Differential-Thermal and X-Ray Analysis of TlFeS2 and TlFeSe2 Chalcogenides , 2018, Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques.

[4]  M. Mirzayev,et al.  Thermophysical Properties of Boron Carbide Irradiated by Ionizing Radiation , 2018 .

[5]  S. Jabarov,et al.  Influence of gamma irradiation on the surface morphology, XRD and thermophysical properties of silicide hexoboride , 2018 .

[6]  F. Cataldo,et al.  Neutron bombardment of boron carbide B12C3: A FT-IR, calorimetric (DSC) and ESR study , 2017 .

[7]  R. Bell,et al.  Impact scenarios in boron carbide: A computational study , 2016 .

[8]  D. Fang,et al.  Fabrication and characterization of B4C–ZrB2–SiC ceramics with simultaneously improved high temperature strength and oxidation resistance up to 1600 °C , 2016 .

[9]  S. Aliev,et al.  Water radiolysis in the presence of uranyl silicate , 2015, Russian Journal of Physical Chemistry A.

[10]  S. Aliev,et al.  Heterogeneous water radiolysis in the presence of uranyl silicate , 2015, Protection of Metals and Physical Chemistry of Surfaces.

[11]  N. Padture,et al.  High-temperature creep deformation of coarse-grained boron carbide ceramics , 2015 .

[12]  R. Kampmann,et al.  Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality , 2015 .

[13]  G. Pellegrini,et al.  Fabrication and nuclear reactor tests of ultra-thin 3D silicon neutron detectors with a boron carbide converter , 2014 .

[14]  R. Hall-Wilton,et al.  B4C thin films for neutron detection , 2012 .

[15]  A. Hadian,et al.  Purification of Attrition Milled Nano-size Boron Carbide Powder , 2012 .

[16]  Celeste Fleta,et al.  Ultra-thin 3D silicon sensors for neutron detection , 2012 .

[17]  Y. Sakka,et al.  Microstructure and high-temperature strength of B4C-TiB2 composite prepared by a crucibleless zone melting method , 2009 .

[18]  S. V. Konovalikhin,et al.  Carbon in boron carbide: The crystal structure of B11.4C3.6 , 2009 .

[19]  D. Emin,et al.  On the crystal structure of boron carbides , 2008 .

[20]  T. Qiu,et al.  Oxidation behaviour of boron carbide powder , 2007 .

[21]  D. Emin,et al.  A proposed boron-carbide-based solid-state neutron detector , 2005 .

[22]  Douglas S. McGregor,et al.  Spectral identification of thin-film-coated and solid-form semiconductor neutron detectors , 2004 .

[23]  C. L. Fink,et al.  A neutron detector to monitor the intensity of transmitted neutrons for small-angle neutron scattering instruments , 2003 .

[24]  R. Klann,et al.  Design considerations for thin film coated semiconductor thermal neutron detectors—I: basics regarding alpha particle emitting neutron reactive films , 2003 .

[25]  J. I. Brand,et al.  A class of boron-rich solid-state neutron detectors , 2002 .

[26]  Douglas S. McGregor,et al.  Thin-film-coated bulk GaAs detectors for thermal and fast neutron measurements , 2001 .