Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially genera...Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator＇s treatment head, patient＇s body, and treat- ment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D20 target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy （BNCT） application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Evaluation of the heavy water photonuclear source.展开更多
In this work, tritium concentration was determined in different D2O enrichment in heavy water samples. Samples were prepared from Arak Heavy Water Production Plant. Tritium concentration was determined utilizing liqui...In this work, tritium concentration was determined in different D2O enrichment in heavy water samples. Samples were prepared from Arak Heavy Water Production Plant. Tritium concentration was determined utilizing liquid scintillation detector (LSC) system based on β-decay of tritium isotope. In this work instead of simple distillation, the azeotropic distillation method was used. Absorbed spectra and fluorescence spectra were registered by Shimadz spectrometer UV-2100 model and fluorescence spectrometer LS50B model respectively. Tritium concentration was obtained from 1.75 ± 0.80 up 6.16 ± 1.01 Bq/L for 0.35% to 77.50% enrichment of D2O concentration in heavy water samples. Coefficient correlation between tritium concentration and D2O concentration in heavy water R2 = 0.853 was derived. For 99.8% enriched D2O in heavy water, deviation was observed from direct line that caused decreasing of R2.展开更多
文摘Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator＇s treatment head, patient＇s body, and treat- ment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D20 target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy （BNCT） application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Evaluation of the heavy water photonuclear source.
文摘In this work, tritium concentration was determined in different D2O enrichment in heavy water samples. Samples were prepared from Arak Heavy Water Production Plant. Tritium concentration was determined utilizing liquid scintillation detector (LSC) system based on β-decay of tritium isotope. In this work instead of simple distillation, the azeotropic distillation method was used. Absorbed spectra and fluorescence spectra were registered by Shimadz spectrometer UV-2100 model and fluorescence spectrometer LS50B model respectively. Tritium concentration was obtained from 1.75 ± 0.80 up 6.16 ± 1.01 Bq/L for 0.35% to 77.50% enrichment of D2O concentration in heavy water samples. Coefficient correlation between tritium concentration and D2O concentration in heavy water R2 = 0.853 was derived. For 99.8% enriched D2O in heavy water, deviation was observed from direct line that caused decreasing of R2.
