Ring artifacts will happen mostly when the detector has inconsistent response among the detector channels,and the characteristic produced rings centered in the iso-center in the reconstructed slices inevitably affect ...Ring artifacts will happen mostly when the detector has inconsistent response among the detector channels,and the characteristic produced rings centered in the iso-center in the reconstructed slices inevitably affect the recognition and analysis of the corresponding sample structures in neutron computed tomography(CT).In this work,a ring correction method based on the projection-field(RCP)is proposed,it is a pre-processing method and provides the corrected projection data directly,which is also conducive to efficient data storage and other algorithmic researches.Simulation and physical experiments are performed for verifying the effect of the method,and one of the correction methods based on the image-field is used for comparison.The results demonstrate that the RCP can correct the ring artifacts well without reducing the image resolution or over-correction.展开更多
The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bu...The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bulk material,which could be benefited from pulsed neutron source.Here we build a Bragg-edge imaging system on the General Purpose Powder Diffractometer at the China Spallation Neutron Source.The residual strain mapping of a bent Q235 ferrite steel sample has been achieved with a spectral resolution of 0.15%by the time-of-flight neutron Bragg-edge imaging on this system.The results show its great potential applications in materials science and engineering.展开更多
We design a new kind of phase zone plates（PZPs） to improve the diffraction efficiency of soft x ray zone plates（ZPs）. The design replaces blank parts of PZPs with metals of negative phase shift at the working ener...We design a new kind of phase zone plates（PZPs） to improve the diffraction efficiency of soft x ray zone plates（ZPs）. The design replaces blank parts of PZPs with metals of negative phase shift at the working energy, which is called as the positive and negative PZPs（PNPZPs）. According to the calculation, PNPZPs have a higher maximum efficiency than conventional ZPs with the same zone width. With the help of a negative phase coefficient, it is much easier to achieve a π phase shift in one period, resulting in a smaller zone height. This design can help fabricate finer PZPs to achieve a better image resolution.展开更多
基金the National Key Research and Development Program of China(Grant Nos.2016YFA0401502 and 2017YFB0701903)the National Natural Science Foundation of China(Grant Nos.U1832219 and 12005166)+3 种基金the Youth Innovation Promotion Association,the Chinese Academy of Sciences(CAS)(Grant No.2017023)the Guangdong Natural Science Foundation,China(Grant No.2016A030313129)the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant Nos.IGGCAS-201903 and SZJJ201901)the Key Research Program,CAS(Grant Nos.YJKYYQ20190043,ZDBS-LY-DQC003,XDA14040401,and KFZD-SW-422).
文摘Ring artifacts will happen mostly when the detector has inconsistent response among the detector channels,and the characteristic produced rings centered in the iso-center in the reconstructed slices inevitably affect the recognition and analysis of the corresponding sample structures in neutron computed tomography(CT).In this work,a ring correction method based on the projection-field(RCP)is proposed,it is a pre-processing method and provides the corrected projection data directly,which is also conducive to efficient data storage and other algorithmic researches.Simulation and physical experiments are performed for verifying the effect of the method,and one of the correction methods based on the image-field is used for comparison.The results demonstrate that the RCP can correct the ring artifacts well without reducing the image resolution or over-correction.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFB0701903 and 2016YFA0401502)the National Natural Science Foundation of China(Grant No.12041202)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2017023)the Guangdong Natural Science Foundation,China(Grant No.2016A030313129)the Department of Science and Technology of Guangdong Province under grant project of energy-resolved neutron imaging instrument.
文摘The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bulk material,which could be benefited from pulsed neutron source.Here we build a Bragg-edge imaging system on the General Purpose Powder Diffractometer at the China Spallation Neutron Source.The residual strain mapping of a bent Q235 ferrite steel sample has been achieved with a spectral resolution of 0.15%by the time-of-flight neutron Bragg-edge imaging on this system.The results show its great potential applications in materials science and engineering.
基金supported by the National Natural Science Foundation of China under Grant No.11305173
文摘We design a new kind of phase zone plates（PZPs） to improve the diffraction efficiency of soft x ray zone plates（ZPs）. The design replaces blank parts of PZPs with metals of negative phase shift at the working energy, which is called as the positive and negative PZPs（PNPZPs）. According to the calculation, PNPZPs have a higher maximum efficiency than conventional ZPs with the same zone width. With the help of a negative phase coefficient, it is much easier to achieve a π phase shift in one period, resulting in a smaller zone height. This design can help fabricate finer PZPs to achieve a better image resolution.
