نتایج جستجو برای: neutron production

تعداد نتایج: 648123  

A new model is presented herein to calculate optimal value for ultra-cold neutron (UCN) production rate of a UCN source. The cold neutron (CN) converter is the main component of UCN source. In this paper, we study the UCN source which contains the D2O neutron moderator, the sD2 converter, 590 Mev proton beam, and the spallation target (a mixture of Pb, D2O and Zr). In order to determine the qua...

Journal: :basic and clinical cancer research 0
hoda darestani 1nuclear engineering department, science and research unit, azad university, tehran, i.r. iran hassan ali nedaie radiotherapy oncology department, cancer institute, tehran university of medical sciences, tehran, i.r. iran azim arbabi radiation oncology department, imam hussein medical center, faculty of medicine, shahid beheshti university of medical sciences, tehran, i.r. iran kheirollah mohammadi nuclear engineering department, amirkabir industrial university, tehran, i.r. iran mahmood allahverdi radiotherapy oncology department, cancer institute, tehran university of medical sciences, tehran, i.r. iran arjang shahvar agricultural, medical and industrial research school, karaj, i.r. iran

background : in spite of clinically useful photon and electron beams, high energy linacs produce secondary particles such as neutrons (photo-neutron production). neutrons have important roles during treatment with high energy photons in terms of protection and dose escalation. in this project, neutron dose equivalent of 18 mv varian accelerators is calculated by tld600 and tld700. materials and...

Background: Neutron contamination is produced in electron beams of linac when tooth or dental materials are located in the path of beam. Objective: This study aims to determine the neutron dose contamination from different dental restoration materials in electron mode of a linac. Material and Methods: In this experimental study, the neutron dose contamination was calculated in the p...

Journal: :journal of biomedical physics and engineering 0
m t bahreyni toossi medical physics department, faculty of medicine, mashhad university of medical sciences, mashhad, iran b khajetash medical physics department, faculty of medicine, mashhad university of medical sciences, mashhad, iran m ghorbani medical physics department, faculty of medicine, mashhad university of medical sciences, mashhad, iran

background: one of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. objective: in the present study the impact of wedge and block on neutron contamination production is investigated. the evaluations are conducted for a 15 mv siemens primus linear accelerator.  methods: simulations were performed using mcnpx mon...

Introduction: One of the concerns about using of high energy photons in radiotherapy is neutron contamination production. The threshold energy of photoneutron production in most materials with high atomic number is about 7MeV. Therefore, it seems to be logical that the main components with high atomic number elements used in the LINAC head have a large contribution to the neutr...

Background: One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment.Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Methods: Simulations were performed using MCNPX Monte...

2000
W. A. Friedman M. B. Tsang D. Bazin W. G. Lynch

The underlying mechanism involved in the production of very neutron-rich nuclides using projectile fragmentation is studied with an abrasion-ablation ~AA! model. The AA model suggests that very neutron-rich nuclides are produced by removing nearly all the required protons in the nonequilibrium abrasion stage, with minimal evaporation of neutrons in the ablation stage—‘‘cold fragmentation.’’ Fur...

Amir Danyaei Farnaz Rahimli Hojattolah Shabazian Mansour Zabihzadeh Mohammad Ali Behrooz

Introduction: Boron neutron capture therapy (BNCT) is recommended to treat the glioblastoma tumor. It is well known that neuron beams are more effective treatment than photon beams to treat hypoxia tumors due to interaction of neutron with nucleus and production of heavy particles such as 7Li and alpha particle. In this study to evaluate the suitability of BNCT for treating of ...

2008
T. Nakamura

The experimental results on DDX (double differential neutron production cross section data), TTY (thick target neutron production yield data), heavy-ion produced neutron transport data, and spallation products production cross section data taken at Heavy Ion Medical Accelerator (HIMAC), National Institute of Radiological Sciences (NIRS), Japan, are presented for heavy ions of He to Xe in the en...

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