An experimental study on nondestructive X-ray imaging of inner structure of soft tissues in phase con-trast has been conducted with Beijing Synchrotron Radiation Facility (BSRF). Modification to the beamline setupwas ...An experimental study on nondestructive X-ray imaging of inner structure of soft tissues in phase con-trast has been conducted with Beijing Synchrotron Radiation Facility (BSRF). Modification to the beamline setupwas made to enlarge the X-ray beam section and consequently larger samples could be imaged. In-line setup was em-ployed for experiments. Results on a series of samples were given and soft-tissue details of less than 50 μm inside afresh goldfish were obtained. Diagnosis of tumor in its early stage was also investigated taking SD rats as the model.Tumor at the size of ～ 100μm was observed. Potential of this technique in clinic diagnosis was discussed.展开更多
The Shanghai Synchrotron Radiation Facility (SSRF) is a proposed 3rd generation light source with 3.5 GeV in energy. It is composed of 20 DBA cells resulting in a ring that is about 10 nm(rad in emittance and 396 m in...The Shanghai Synchrotron Radiation Facility (SSRF) is a proposed 3rd generation light source with 3.5 GeV in energy. It is composed of 20 DBA cells resulting in a ring that is about 10 nm(rad in emittance and 396 m in circumference, and provides 10 straight sections of 7.24 m and other 10 straight sections of 5.0 m for the inclusion of insertion devices, injection components and RF cavities. The lattice has high flexibility, and the tunes and beta functions can be easily adjusted within a wide range to meet the requirements for different operation modes, including high beta mode and hybrid beta mode with and/or without dispersion in straight sections. In this paper, the results of linear optics design and dynamic aperture study are presented.展开更多
In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback inthe SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points i...In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback inthe SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points issmaller than the orbit stability requirements in horizontal plane, but exceeds the orbit stability requirements in verticalplane. A dynamic global orbit feedback system, which consists of 38 high-bandwidth air-coil correctors and 40high-precise BPMs, is proposed to suppress the vertical beam orbit position movement. Numerical simulations showthat this dynamic orbit feedback system can stabilize the vertical beam orbit position movement in the frequencyrange up to 100 Hz.展开更多
The wake field, impedance and output signal for SSRF BPM have been calculated and analyzed by us-ing the numerical simulation code of MAFIA. The narrow-band impedance of BPM arising from formation of reso-nance in its...The wake field, impedance and output signal for SSRF BPM have been calculated and analyzed by us-ing the numerical simulation code of MAFIA. The narrow-band impedance of BPM arising from formation of reso-nance in its cavity like structure either is harmful to beam or limits the performance of BPM itself, and should be re-duced to tolerable levels. The calculated results show that there are three main peaks in the impedance spectrum ofthe SSRF BPM prototype, and two of which are above the limit. After lots of simulations for different shapes of theBPM button, a new structure of SSRF BPM have been found, and there is only one main peak, which is under thelimit, in the impedance spectrum. Its output signal also meets the requirement.展开更多
Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is...Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is es- sential for operations. The tuning is achieved by synchronizing the drive signal and the cavity probe signal. The error signal defined as their subtraction is amplified and used to drive a stepping motor, which in turn moves a metallic plunger in or out of the cavity by programmable logic controller (PLC). The tune speed is set to be 1kHz/s.展开更多
基金National Natural Science Foundation of China(No.10275087)Shanghai Foundation on Development of Science and Technology(No.022261023) Shanghai Foundation for Natural Science(No.02ZF14116)
文摘An experimental study on nondestructive X-ray imaging of inner structure of soft tissues in phase con-trast has been conducted with Beijing Synchrotron Radiation Facility (BSRF). Modification to the beamline setupwas made to enlarge the X-ray beam section and consequently larger samples could be imaged. In-line setup was em-ployed for experiments. Results on a series of samples were given and soft-tissue details of less than 50 μm inside afresh goldfish were obtained. Diagnosis of tumor in its early stage was also investigated taking SD rats as the model.Tumor at the size of ～ 100μm was observed. Potential of this technique in clinic diagnosis was discussed.
文摘The Shanghai Synchrotron Radiation Facility (SSRF) is a proposed 3rd generation light source with 3.5 GeV in energy. It is composed of 20 DBA cells resulting in a ring that is about 10 nm(rad in emittance and 396 m in circumference, and provides 10 straight sections of 7.24 m and other 10 straight sections of 5.0 m for the inclusion of insertion devices, injection components and RF cavities. The lattice has high flexibility, and the tunes and beta functions can be easily adjusted within a wide range to meet the requirements for different operation modes, including high beta mode and hybrid beta mode with and/or without dispersion in straight sections. In this paper, the results of linear optics design and dynamic aperture study are presented.
文摘In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback inthe SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points issmaller than the orbit stability requirements in horizontal plane, but exceeds the orbit stability requirements in verticalplane. A dynamic global orbit feedback system, which consists of 38 high-bandwidth air-coil correctors and 40high-precise BPMs, is proposed to suppress the vertical beam orbit position movement. Numerical simulations showthat this dynamic orbit feedback system can stabilize the vertical beam orbit position movement in the frequencyrange up to 100 Hz.
文摘The wake field, impedance and output signal for SSRF BPM have been calculated and analyzed by us-ing the numerical simulation code of MAFIA. The narrow-band impedance of BPM arising from formation of reso-nance in its cavity like structure either is harmful to beam or limits the performance of BPM itself, and should be re-duced to tolerable levels. The calculated results show that there are three main peaks in the impedance spectrum ofthe SSRF BPM prototype, and two of which are above the limit. After lots of simulations for different shapes of theBPM button, a new structure of SSRF BPM have been found, and there is only one main peak, which is under thelimit, in the impedance spectrum. Its output signal also meets the requirement.
文摘Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is es- sential for operations. The tuning is achieved by synchronizing the drive signal and the cavity probe signal. The error signal defined as their subtraction is amplified and used to drive a stepping motor, which in turn moves a metallic plunger in or out of the cavity by programmable logic controller (PLC). The tune speed is set to be 1kHz/s.
