On May 6, 2009, the X-ray imaging and biomedical application beamline(BL13W1) at Shanghai Synchrotron Radiation Facility(SSRF) officially opened to users, with 8–72.5 ke V X-rays. The experimental station is equipped with four sets of X-ray CCD detectors of different pixel size(0.19–24 μm) for on-line phase-contrast imaging and micro-CT imaging with 0.8 μm spatial resolution and 1 ms temporal resolution. An in vivo microCT experiment for a living insect was realized in 4 s. An X-ray fluorescence detector is equipped for X-ray fluorescence mapping imaging and X-ray fluorescence micro-CT imaging with 50 μm spatial resolution. In order to meet different requirements from the users, several experimental methods, such as X-ray spiral micro-CT, Xray local micro-CT, X-ray fast micro-CT, X-ray grating-based differential micro-CT, X-ray fluorescence microCT and X-ray quantitative micro-CT have been developed, and nearly 60 papers related to those developments for this beamline have been published. Moreover, the beamline has realized the remote fast CT reconstruction,providing a great convenience for the users to process experimental data at their offices. As of August 2014,the beamline has offered the user beamtime of(23 145 h), from which 232 user papers have been published,including 151 SCI papers and 55 papers with SCI impact factor > 3. The quantity and quality of the user paper outcome keep a steady increase. Some typical user experimental results are introduced.
The computed tomography imaging of a local region inside a sample with a size larger than the field of view is particularly important for synchrotron X-ray imaging.In this letter,an improved algorithm is proposed to reconstruct the local structure inside a sample using almost completely local data.The algorithm significantly reduces the X-ray radiation dose and improves computational efficiency.Simulation results show that the new algorithm works well and has a higher reconstruction precision than previous methods,as confirmed by experimental results carried out at the Shanghai Synchrotron Radiation Facility.
X-ray tomography of samples containing both weakly and strongly absorbing materials are necessary in material and biomedical imaging. Extending the validity of the phase-attenuation duality （PAD） method, the propagation-based phase-contrast computed tomography （PPCT） of a sample with hybrid composi- tions of both the light and dense components with 60 keV of synchrotron radiation is investigated. The experimental results show that the PAD-based PPCT is effective in imaging both the weakly and strongly absorbing components simultaneously. Compared with the direct PPCT technique, the PAD-based PPCT technique demonstrates its excellent capability in material discrimination and characterization. In addi- tion, the PAD-based PPCT exhibits a striking performance on the image contrast enhancement and noise suppression. Therefore, this technique is useful for material and biomedical imaging applications, espe- cially when the radiation dose involved imposes a serious constraint.
With the spatial coherence of X-rays and high flux and brightness of the 3rd generation synchrotron radiation facility,X-ray phase contrast microscopy(XPCM)at Shanghai Synchrotron Radiation Facility(SSRF)can provide high resolution dynamic imaging of low electron density materials in principle.In this paper,we investigated the cavitation and water-refilling processes in rice and bamboo leaves utilizing XPCM at SSRF.The occurrence of xylem cavitation was recorded in vivo.The study also revealed that under different dehydration conditions,cavitation occurs in different degrees,and therefore,the refilling process is different.The results demonstrate that SSRF can provide high enough fluxes to study dynamic processes in plants in real-time,and XPCM is expected to be a promising method to reveal the mechanisms of cavitation and its repair in plants nondestructively.
