http://103.7.193.12:8080/xmlui/handle/123456789/40 DEPARTMENT OF PHYSICS (PHY) Sun, 25 Oct 2026 10:18:17 GMT 2026-10-25T10:18:17Z http://103.7.193.12:8080/xmlui/handle/123456789/2254 SIMULATION AND ANALYSIS OF TMDC SOLAR CELLS UNDER PROTON RADIATION USING MONTE-CARLO METHODS, SCAPS, AND MACHINE LEARNING TECHNIQUES RAHMAN, NAIMUR The space-based energy solutions are currently relying on expensive silicon-based solar cells. In recent years, perovskite materials are also participating in this area as thin-film third generation solar cells. However, these materials come with built-in drawbacks against radiation environments. To address this issue, this research explores the possibility of using transition metal dichalcogenide (TMDC) materials as absorbers in space solar cells. Proton radiation is a common and primary occurrence in space. Hence, we investigated the effect of 0.15 MeV and 3 MeV proton radiation on four different TMDC heterojunction thin-film solar cells with frequently used hole and electron transport materials. We have used SR-NIEL web application, Monte-Carlo simulation toolkit SRIM, solar cell capacitance simulation SCAPS-1D, and machine learning analysis for evaluating the energy loss, defect creation and performance analysis. For 0.15 MeV and 3 MeV proton radiation, energy loss to ionization by ions, energy loss to ionization by recoils, energy loss to phonons by ions, energy loss to phonons by recoils, energy from ions, vacancies by ions, and replacement collisions are calculated. MoS2 and MoSe2 had higher power conversion efficiencies (PCE) of 28.16% and 28.11%, respectively, while WSe2 and WS2 had high short-circuit current densities (Jsc) of 39.36 mA/cm2 and 35.15 mA/cm2, respectively, under standard operating conditions (AM 1.5G, 1000 W/m2 incident photon flux). However, when exposed to 0.15 MeV proton radiation, the performance of all devices significantly decreased. MoSe2 and WS2 had relatively higher PCEs of 19.47% and 17.01%, respectively, compared to WSe2 and MoS2, indicating some resistance to radiation-induced deterioration. Machine learning predictions revealed that WS2 and WSe2 are more sensitive to proton radiation than MoSe2 and MoS2 absorbers. This implies that, despite their possibility for high Jsc and efficient power generation, WS2 and WSe2-based solar cells may be less suitable for areas with high proton radiation, as their performance can decrease rapidly under such conditions. MoSe2 and MoS2 absorber-based solar cells, on the other hand, appear to be more resistant to the negative effects of proton radiation, making them better candidates for use in radiation-rich areas. These findings emphasize the relevance of material robustness to radiation when building solar cells for space or radiation environments, as well as the promise of MoSe2 and MoS2 absorbers in such applications. SIMULATION AND ANALYSIS OF TMDC SOLAR CELLS UNDER PROTON RADIATION USING MONTE-CARLO METHODS, SCAPS, AND MACHINE LEARNING TECHNIQUES; A Thesis Submitted in partial fulfillment of the requirements for the degree of Master of Science (MS) in the Department of Physics, Hajee Mohammad Danesh Science and Technology University, Dinajpur-5200 Submitted By NAIMUR RAHMAN, Student ID: 1708105, Session: 2021-2022, DEPARTMENT OF PHYSICS; HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR-5200; BANGLADESH. Wed, 01 Jan 2025 00:00:00 GMT http://103.7.193.12:8080/xmlui/handle/123456789/2254 2025-01-01T00:00:00Z http://103.7.193.12:8080/xmlui/handle/123456789/2247 CTDI Volume Measurement of CT Simulation and CT Effective Dose Calculation for Cervix and Prostate Sohag, Mahfuzur Rahman The accurate measurement of Computed Tomography Dose Index (CTDI) volume and the calculation of effective dose are crucial in optimizing patient safety and ensuring the efficacy of CT simulations in radiation therapy. This study focuses on evaluating the CTDI volume during CT simulations and calculating the effective dose for patients undergoing treatment for cervical and prostate cancers. By using phantoms and patient-specific data, this study aims to quantify the radiation dose distribution and assess the potential risks associated with these diagnostic procedures. The present retrospective study was conducted on 53 cervical and prostate cancer patients (6 prostate and 47 cervical) with ages ranging from 35 to 75 years. The examinations were carried out using a Philips Ingenuity Time-of-Flight (ToF) 64 slice PET/CT system (Philips Healthcare, Cleveland, OH, USA) at the Institute of Nuclear Medical Physics, Atomic Energy Research Establishment (AERE), Savar, Dhaka. The scans were performed according to institutional protocols. Dose measurements were carried out in terms of CTDI100. CTDI100 values for the center and periphery of the phantom were recorded, and the average value of the periphery doses was taken. Then, CTDIw was calculated using CTDI100 values. Since an axial CT scan was taken on the phantom, there was no patient table movement, making CTDIvol values the same as CTDIw values. The mean±SD CTDIvol was obtained as 18.879±5.914 mGy, ranging from 8.952 to 37.327 mGy. The CT effective doses were calculated using the dose conversion coefficient k=0.015 mSv.mGy-1.cm-1 for the pelvic region, as described in the American Association of Physicists in Medicine Report No. 96. The effective doses for the CT procedure were estimated using DLP values that represent radiation exposure over the entire scan length. The scan lengths were generated by the scanner, and the DLP values were measured as the product of CTDIvol and scan length. The DLP values ranged from 411.225 to 2030.96 mGy·cm, with a mean value of 1094.479±462.029 mGy·cm. The effective dose is the product of the DLP and the conversion coefficient k. The mean effective dose for the pelvic region was 16.271±7.180 mSv. The doses for prostate patients were 15.125±8.815 mSv, and for cervical patients, they were 16.417±8.930 mSv. The present study found these values to be moderately higher compared to the effective dose values of conventional diagnostic radiology examinations. This is because the CT scans were performed on the patients as part of radiotherapy treatment planning, and the scan lengths were longer than the pelvic region, resulting in higher effective doses. However, this study suggests that the risk-benefit ratio of any radiological scan should be clarified and carefully weighed. CTDI Volume Measurement of CT Simulation and CT Effective Dose Calculation for Cervix and Prostate; Submitted by Mahfuzur Rahman Sohag, Student ID: 1708109, Session: 2021-2022; MS Student Department of Physics, HSTU, Dinajpur-5200, Bangladesh; Mon, 01 Jul 2024 00:00:00 GMT http://103.7.193.12:8080/xmlui/handle/123456789/2247 2024-07-01T00:00:00Z