Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 12 1 2025 01 01 136 142 Saeedeh Khezripour Department of Molecular and Atomic Physics, Faculty of Modern Science and Technology, Graduate University of Advanced Technology, Kerman, Iran Mohammad Reza Rezai Rayeni Department of Nuclear Engineering, Faculty of Modern Sciences and Technologies, Graduate University of Advanced Technology, Kerman, Iran 2024 06 27 2024 09 16 Purpose: The paper aims to discuss the response of the Micro-Mesh Gaseous Structure (Micromegas) detector to high-energy X-ray with 2.3 MeV energy using photon to neutron converters in addition to optimization of the detector components by Monte Carlo simulation. Materials and Methods: Methods of using Micromegas are different in terms of energy and intensity of high-energy X-ray. Response of Micromegas detector to X-ray with 2.3 MeV by different photoneutron converters was calculated by Monte Carlo N Particle X-Version (MCNPX) code. The number of electrons in the drift and multiplication regions and the depth-dose in the various regions of the detector were measured to study the response of the Micromegas detector to high energy X-ray. Also, the thickness of the upper electrode, and the type of gas in the detector were studied and optimized. Results: D2O with 2×10-5 efficiency is the best target to convert photons with 2.3 MeV energy to neutrons. It is the proper convertor to change the high energy X-ray into a photoneutron that can be detected by Micromegas. The optimum thickness of the upper electrode is 0.0026 cm for air and P10 gas in the detector. Conclusion: The results show that this detector can detect high-energy X-rays with energy above 2 MeV. The Monte Carlo results showed the output current of the Micromegas detector is 5.12 pA per one input hard X-ray photon. https://fbt.tums.ac.ir/index.php/fbt/article/view/1052 https://fbt.tums.ac.ir/index.php/fbt/article/download/1052/460