نوع مقاله: مقاله پژوهشی
نویسندگان
1 دانشکده فیزیک، دانشگاه آزاد تهران، واحد مرکزی، صندوق پستی: 86831-14676، تهران ـ ایران
2 پژوهشکدهی لیزر و اپتیک، پژوهشگاه علوم و فنون هستهای، سازمان انرژی اتمی، صندوق پستی: 1339-14155، تهران ـ ایران
3 پژوهشکدهی فیزیک و شتابگرها، پژوهشگاه علوم و فنون هستهای، سازمان انرژی اتمی، صندوق پستی: 1339-14155، تهران ـ ایران
چکیده
ابتدا با بمباران هدفهای جامد به وسیلهی طیفهای الکترونهای تولید شده از برهمکنش لیزر- پلاسما، تولید پرتو ایکس ترمزی با استفاده از کد MCNPX شبیهسازی شد. سپس شبیهسازی تولید نوترون از برهمکنش فوتونهای پرتو ایکس با هدف جامد ثانویه به انجام رسید. هدف از انجام این کار ارزیابی پارامترهای مناسب چشمهی الکترون و هدف برای تولید مؤثر فوتون و نوترون بود. بدینترتیب امکان تعیین بهترین شرایط چشمه و هدف از جمله جنس و ضخامت بهینهی هدف، طیف مناسب الکترون، و زاویهی بهینه گسیل فوتون برای افزایش بازده تولید پرتو ایکس فراهم میآید. این کار به نوبهی خود به بهبود تولید شار فوتونوترون برای کاربردهای مختلف از جمله پزشکی منجر
میشود. یافتهها نشان داد که با افزایش انرژی بیشینهی الکترون، ضخامت بهینه و بازده خروجی افزایش مییابد. همچنین برای مواد با چگالی و عدد اتمی بزرگتر، افزایش گسیل فوتونهای ترمزی که در ضخامتهای کوچکتر روی میدهد، منجر به تولید بیشتر شار نوترون میشود.
کلیدواژهها
عنوان مقاله [English]
Simulation of Bremsstrahlung X-ray and photo-neutron generation via interaction of laser-produced electrons with solid targets
نویسندگان [English]
- Saeideh Najafi 1
- Lida Nikzad 2
- Zafar Riazi 3
چکیده [English]
In this paper, first, with bombardment of solid targets via spectra of electrons produced from the laser–plasma interaction, the created Bremsstrahlung X-ray is simulated using MCNPX code. Then, by the interaction of the produced photons with a secondary solid target, a simulation for the neutron generation is studied. The purpose of this work is to evaluate appropriate parameters of electron source and target to create photons and neutrons, more efficiently. Therefore, we are able to estimate the best conditions for the source and target, for instance, the optimum selection of the target material and its thickness, proper electron spectrum, and the optimum angle of photon emission so as to increase the efficiency of X-ray generation. This results in improved production of photo-neutron flux to be used in various applications such as medical uses. The results show that by increasing the electron peak energy, the optimum thickness and output efficiency are enhanced. Furthermore, for materials with higher density and atomic number, the increment of Bremsstrahlung photon emission, which occurs at smaller thicknesses, results in greater generation of neutron flux.
کلیدواژهها [English]
- Bremsstrahlung X-rays
- Photo-neutron generation
- Laser-produced electrons
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