Evaluation of gamma ray attenuation properties of boron carbide (B₄C) doped AISI 316 stainless steel: Experimental, XCOM and Phy-X/PSD database software

Abstract

This study aimed to investigate the gamma-ray attenuation properties of AISI 316 stainless steel both experimentally and theoretically by doping different ratios of boron carbide. In the experimental measurements, a gamma spectroscopy system with a NaI(Tl) detector was used and ⁶⁰Co, ¹³⁷Cs radioactive sources were used as gamma sources. In addition, it was calculated theoretically using XCOM and Phy-X/PSD database software. With the help of both experimental and theoretical results obtained, the effect of adding boron carbide to AISI 316 stainless steel on the change of the linear attenuation coefficients (LAC, µ) of the steel was investigated. Experimental LAC results for 3 different gamma energies of steels have been checked with the calculated theoretical LAC results by XCOM database using the chemical contents and density of the steel samples. It has been observed that the experimental and theoretical results are compatible with each other. Also, by using experimentally obtained LACs, half and tenth value layer thickness, mean free path and radiation protection efficiency parameters were calculated. In addition to these parameters, parameters such as equivalent atomic number (Z_eq), effective atomic number (Z_eff), exposure accumulation factor (EBF) were theoretically determined in the energy range of 0.015–15 MeV for steel samples produced using the Phy-X / PSD software. From the experimental results obtained, as the ratio of boron carbide in AISI 316 stainless steel increases, LACs and radiation protection efficiency (RPE) values decrease. Other parameters, transmission speed, HVL, TVL and MFP values increased with increasing boron carbide (B₄C) ratio. It can be said that different processes are effective in different energy regions for the Z_eff, Z_eq and EBF results obtained theoretically. From these data, it can be concluded that adding boron carbide to AISI 316 stainless steel reduces the steel's ability to attenuate gamma radiation.

Introduction

Stainless steels, known as materials that do not stain or corrode, are defined as steels that contain at least 10% chromium by combining various metals in different proportions. AISI 316 steel, which is classified as austenitic stainless steel, is used in areas and applications such as engine parts of many vehicles that require corrosion-resistant materials, pharmaceutical production areas, equipment using chemical materials, machines used in purification processes and devices used for medical applications [1], [2], [3]. AISI 316 austenitic stainless steels consist 16.5–18.5% Chromium (²⁴Cr), 10–13% Nickel (²⁸Ni), 2–3% Molybdenum (⁴²Mo), 2% Manganese (²⁵Mn), 1% Silicon (¹⁴Si) and small amounts of Carbon (⁶C), Phosphorus (¹⁵P), Sulfur (¹⁶S). The remaining part of these elements in AISI 316 stainless steel is iron. Many researchers have conducted studies to investigate the physical and mechanical properties of stainless steel [4], [5], [6].

Boron carbide is a non-oxide ceramic material that has a special place in the important hard nonmetal group such as SiC, Si₃N₄, diamond, alumina [7]. Boron carbide has good mechanical properties, high melting temperature, high hardness, low density, high radiation absorption. In addition, it is highly resistant to chemical substances. Boron carbide comes after diamond and cubic boron nitride in the hardest materials ranking. The main areas of use of boron carbide include spray nozzles, mold materials used in wire drawing, absorbent materials in nuclear reactors [8]. In addition, due to some superior properties such as low density, high elastic modulus and hardness, boron carbide-based ceramic-metal composites used in armor material have become the focus of attention of researchers [9], [10], [11], [12].

With technological developments, today radiation has a wide range of uses such as industrial applications, scientific studies, agricultural activities, medicine (radiotherapy applications and imaging). Ionizing radiation used in these areas directly (radioactive sources, natural radioactivity, etc.) or indirectly (leakage, scatter, etc.) exposure affects the health of living things and the environment. For this reason, the issue of radiation protection has gained great importance in terms of health. Time, distance and shielding are the three basic principles of radiation protection. The principle of shielding is the use of barrier material between the radiation source and the system to be protected in order to attenuate or hold different types of radiation (X-ray, gamma ray, particle, etc.). The best known traditional material in terms of radiation shield is lead (Pb). Lead is not used much because of its disadvantages such as poor mechanical properties, high cost, Pb toxicity for humans and the environment. For this reason, the production of new types of materials for radiation protection is increasing. In the literature, many physicists and materials scientists have produced many different types of materials as radiation shielding materials and examined the radiation shielding properties of these materials [13], [14], [15], [16], [17], [18], [19], [20], [21]. In these studies, mentioned in the literature, the radiation attenuation factors were tried to be determined experimentally by using detector systems based on how much the gammas emitted from different radioactive sources are absorbed by the material. Software such as Phy-X/PSD and XCOM [22], [23] are frequently used in the theoretical determination of radiation shielding parameters of materials.

In the studies conducted by the researchers on steel, it is seen that the radiation shielding properties of different steels are examined using the boronizing technique [14], [24], [25], [26]. The novelty of this study, which we have done, unlike other studies, is to examine the radiation shielding properties of the steel produced by adding boron carbide instead of boronizing technique.

This study aims to investigate the variation of linear attenuation coefficient for gamma rays with different energies by adding different ratios of boron carbide to AISI 316 stainless steel, experimentally using gamma spectroscopy system and theoretically using XCOM and Phy-X/PSD software. In addition, we used XCOM and Phy-X/PSD software to compare experimental results with theoretical results and to determine gamma radiation shielding parameters.