We report a new method for measuring particle size distribution (PSD) and refractive index of the top layer ill a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearl...We report a new method for measuring particle size distribution (PSD) and refractive index of the top layer ill a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearly polarized light. The polarization gating technique is used to decouple the single and multiple scattering components in the returned signal. The theoretical model based on Mie theory is presented and a nonlinear inversion method -floating genetic algorithm - is applied to inverting the azimuth dependence of component of polarization light baekscattered. The experiment results demonstrate that the size distribution and refractive index of the scatters of the top layer can be determined by measuring and analyzing the differential signal of the parallel and perpendicular components from a two-layer tissue phantom. The method implies to detect precancerous changes in human epithelial tissue.展开更多
The Shanghai Laser Electron Gamma Source(SLEGS)is a powerful gamma source that provides MeV gamma-ray beams for nuclear science and technology.It was developed as one of the 16 beamline stations in the Phase Ⅱ Projec...The Shanghai Laser Electron Gamma Source(SLEGS)is a powerful gamma source that provides MeV gamma-ray beams for nuclear science and technology.It was developed as one of the 16 beamline stations in the Phase Ⅱ Project of the Shanghai Synchrotron Radiation Facility.The slant-scattering mode is for the first time systematically employed in laser Compton scattering at SLEGS to produce energy-tunable quasi-monoenergetic gamma-ray beams.The SLEGS officially completed its commissioning from July to December 2021.Gamma rays in the energy range of 0.25-21.7 MeV with a flux of 2.1×10^(4)-1.2×10^(7) photons/s and an energy spread of 2-15% were produced during the test.This paper reports the results from commissioning the SLEGS beamline.展开更多
This study examined how the signals of interest (SOI) effect on the backscattering measurement numerically based on 3-D finite-difference time-domain (FDTD) method. High resolution microstructure mappings of bovin...This study examined how the signals of interest (SOI) effect on the backscattering measurement numerically based on 3-D finite-difference time-domain (FDTD) method. High resolution microstructure mappings of bovine cancellous bones provided by micro-CT were used as the input geometry for simulations. Backscatter coefficient (BSC), integrated backscatter coefficient (IBC) and apparent integrated backscatter (AIB) were calculated with changing the start (L1) and duration (L2) of the SOl. The results demonstrated that BSC and IBC decrease as L1 increases, and AIB decreases more rapidly as L1 increases. The backscattering parameters increase with fluctuations as a function of L2 when L2 is less than 6 mm. However, BSC and IBC change little as L2 continues to increase, while AIB slowly decreases as L2 continues to increase. The results showed how the selections of the SOI effect on the backscattering measurement. An explicit standard for SOl selection was proposed in this study and short L1 (about 1.5 mm) and appropriate L2 (6 mm-12 mm) were recommended for the calculations of backscattering parameters.展开更多
基金This work was carried out at the Key Laboratory of Biomedical Photonics of Ministry of Education,Huazhong University of Science and TechnologyThis research was supported by the National Natural Science Foundation of China (No. 30470460 and 60278017)
文摘We report a new method for measuring particle size distribution (PSD) and refractive index of the top layer ill a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearly polarized light. The polarization gating technique is used to decouple the single and multiple scattering components in the returned signal. The theoretical model based on Mie theory is presented and a nonlinear inversion method -floating genetic algorithm - is applied to inverting the azimuth dependence of component of polarization light baekscattered. The experiment results demonstrate that the size distribution and refractive index of the scatters of the top layer can be determined by measuring and analyzing the differential signal of the parallel and perpendicular components from a two-layer tissue phantom. The method implies to detect precancerous changes in human epithelial tissue.
基金supported by the National Natural Science Foundation of China(Nos.11875311,11905274,12005280)the Chinese Academy of Sciences President’s International Fellowship Initiative(No.2021VMA0025).
文摘The Shanghai Laser Electron Gamma Source(SLEGS)is a powerful gamma source that provides MeV gamma-ray beams for nuclear science and technology.It was developed as one of the 16 beamline stations in the Phase Ⅱ Project of the Shanghai Synchrotron Radiation Facility.The slant-scattering mode is for the first time systematically employed in laser Compton scattering at SLEGS to produce energy-tunable quasi-monoenergetic gamma-ray beams.The SLEGS officially completed its commissioning from July to December 2021.Gamma rays in the energy range of 0.25-21.7 MeV with a flux of 2.1×10^(4)-1.2×10^(7) photons/s and an energy spread of 2-15% were produced during the test.This paper reports the results from commissioning the SLEGS beamline.
基金supported by the National Natural Science Foundation of China(Grant No. 11174060)the Ph.D. Programs Foundation of the Ministry of Education of China(Grant Nos. 20090071110066,20110071130004)+1 种基金the Key Science and Technology Program of Shanghai(Grant No. 09441900400)the Program for New Century Excellent Talents in University(Grant No. NCET-10-0349)
文摘This study examined how the signals of interest (SOI) effect on the backscattering measurement numerically based on 3-D finite-difference time-domain (FDTD) method. High resolution microstructure mappings of bovine cancellous bones provided by micro-CT were used as the input geometry for simulations. Backscatter coefficient (BSC), integrated backscatter coefficient (IBC) and apparent integrated backscatter (AIB) were calculated with changing the start (L1) and duration (L2) of the SOl. The results demonstrated that BSC and IBC decrease as L1 increases, and AIB decreases more rapidly as L1 increases. The backscattering parameters increase with fluctuations as a function of L2 when L2 is less than 6 mm. However, BSC and IBC change little as L2 continues to increase, while AIB slowly decreases as L2 continues to increase. The results showed how the selections of the SOI effect on the backscattering measurement. An explicit standard for SOl selection was proposed in this study and short L1 (about 1.5 mm) and appropriate L2 (6 mm-12 mm) were recommended for the calculations of backscattering parameters.