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Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutron source for boron neutron capture therapy
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作者 Yi-Nan Zhu Zuo-Kang Lin +3 位作者 Hai-Yan Yu Ye Dai Zhi-Min Dai Xiao-Han Yu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第3期170-180,共11页
Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear reaction.Among various neutron sources,acce... Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear reaction.Among various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT applications.The^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional benefits.This study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head phantom.The study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 MeV.Furthermore,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes. 展开更多
关键词 Boron neutron capture therapy ^(7)Li(p n)7Be neutron source Incident proton energy Monte Carlo simulation
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Joint inversion of P-wave velocity and Vp–Vs ratio: imaging the deep structure in NE Japan 被引量:5
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作者 王志 《Applied Geophysics》 SCIE CSCD 2014年第2期119-127,252,共10页
A new inversion scheme is presented to obtain three-dimensional images of P-wave velocity(Vp) and P–S-wave velocity ratio(Vp/Vs) using P- and S-phase pairs, i.e., the same source–receiver pairs for the P- and S-... A new inversion scheme is presented to obtain three-dimensional images of P-wave velocity(Vp) and P–S-wave velocity ratio(Vp/Vs) using P- and S-phase pairs, i.e., the same source–receiver pairs for the P- and S-wave arrival-time data. The S-wave velocity(Vs) was separately inverted using the S-phase arrival times. The earthquake hypocenters were simultaneously relocated in the joint inversion. The method considers the Vp/Vs anomaly as a model parameter in the inversion. The proposed method thus provides a more robust calculation of the Vp/Vs anomaly than the conventional method of dividing Vp by Vs. The method also takes into account the ray path difference between P- and S-waves, and hence yields a less biased Vp–Vs ratio than the method of inverting S–P-wave data for Vp and Vp/Vs anomalies under the assumption of identical P and S ray paths. The proposed method was used to image the crust and upper mantle in northeastern(NE) Japan taking advantage of a large number of high-quality arrival times of P- and S-wave source–receiver pairs. The inverted structures suggest that the subducting slab of the Pacific plate is an inclined zone of high-Vp and Vs anomalies with low Vp/Vs perturbation. The mantle wedge is characterized by low-Vp, low-Vs, and high-Vp/Vs anomalies at shallow depths beneath active volcanoes. These features are also observed at greater depths in the back-arc region. Although these features have been previously reported, the Vp/Vs anomaly pattern obtained in this study shows much less scatter and is much better correlated with the seismic velocity perturbation patterns than previous studies. The proposed method can be used, in conjunction with velocity anomaly patterns, to quantify thermal processes associated with plate subduction. 展开更多
关键词 Seismic tomography p and S source–receiver pairs pacific subduction zone Mantle wedge
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Systematic study of the(n,2n)reaction cross section for^(121)Sb and^(123)Sb isotopes
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作者 R.K.Singh N.L.Singh +7 位作者 R.D.Chauhan Mayur Mehta S.V.Suryanarayana Rajnikant Makwana B.K.Nayak H.Naik Tarak Nath Nag K.Katovsky 《Chinese Physics C》 SCIE CAS CSCD 2022年第5期77-94,共18页
The cross sections of the^(121)Sb(n,2n)^(120)Sb^(m) and ^(123)Sb(n,2n)^(122)Sb reactions were measured at 12.50,15.79 and 18.87 MeV neutron energies relative to the standard ^(27)Al(n,α)^(24)Na monitor reaction using... The cross sections of the^(121)Sb(n,2n)^(120)Sb^(m) and ^(123)Sb(n,2n)^(122)Sb reactions were measured at 12.50,15.79 and 18.87 MeV neutron energies relative to the standard ^(27)Al(n,α)^(24)Na monitor reaction using neutron activation and offline γ-ray spectrometry.Irradiation of the samples was performed at the BARC-TIFR Pelletron Linac Facility,Mumbai,India.The quasi-monoenergetic neutrons were generated via the ^(7)Li(p,n)reaction.Statistical model calculations were performed by nuclear reaction codes TALYS(ver.1.9)and EMPIRE(ver.3.2.2)using various input parameters and nuclear level density models.The cross sections of the ground and the isomeric state as well as the isomeric cross section ratio were studied theoretically from reaction threshold to 26 MeV energies.The effect of pre-equilibrium emission is also discussed in detail using different theoretical models.The present measured cross sections were discussed and compared with the reported experimental data and evaluation data of the JEFF-3.3,ENDF/B-VIII.0,JENDL/AD-2017 and TENDL-2019 libraries.A detailed analysis of the uncertainties in the measured cross section data was performed using the covariance analysis method.Furthermore,a systematic study of the(n,2n)reaction cross section for^(121)Sb and^(123)Sb isotopes was also performed within 14-15 MeV neutron energies using various systematic formulae.This work helps to overcome discrepancies in Sb data and illustrate a better understanding of pre-equilibrium emission in the(n,2n)reaction channel. 展开更多
关键词 ANTIMONY (n 2n)reaction cross section 7Li(p n)reaction neutron source neutron activation and offlineγ-ray spectrometry systematic formulae covariance analysis TALYS(ver.1.9)and EMpIRE(ver.3.2.2)codes
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