RF circuit board has a significant impact on performance of the Digital Beam Position Monitor (DBPM) in storage ring of a synchrotron radiation facility.In this paper,a front-end RF board is designed for DBPM,and sche...RF circuit board has a significant impact on performance of the Digital Beam Position Monitor (DBPM) in storage ring of a synchrotron radiation facility.In this paper,a front-end RF board is designed for DBPM,and schematics of the RF board and the test results are given.In view of the inevitable inconsistency in the multi-channel circuit,a calibration circuit is designed to reduce such an influence.The test results show that the calibration method is useful for beam current dependence which is sensitive to channels inconsistency.展开更多
In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of r...In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of radio frequency(RF) front end and high speed data acquisition board.The beam position resolution in the CBPM signal processing system is superior to 1μm.Two signal processing algorithms,fast Fourier transform(FFT) and digital down converter(DDC),are evaluated offline using MATLAB platform,and both can be used to achieve,the CW input signal,position resolutions of 0.31μm and 0.10μm at -16 dBm.The DDC algorithm for its good compatibility is downloaded into the FPGA to realize online measurement,reaching the position resolution of 0.49μm due to truncation error.The whole system works well and the performance meets design target.展开更多
Masks are critical elements of synchrotron radiation front end that are exposed to high temperature and stress.The absorber material is typically comprised of dispersion-strengthened copper,which can retain high perfo...Masks are critical elements of synchrotron radiation front end that are exposed to high temperature and stress.The absorber material is typically comprised of dispersion-strengthened copper,which can retain high performance at elevated temperature.Joining processes under vacuum,including brazing and electron beam welding,are novel approaches for prolonging the absorber and for reducing power densities.The mechanical properties of brazed joints and electron beam welded joints of dispersion-strengthened copper workpieces are evaluated by tensile testing at 20,100,and 200 C.The testing results indicate that the tensile strength and elongation of both vacuum joints decrease with increasing temperature.Compared to brazed joints,electron beam welded joints have higher tensile strength,better ductility,and more stable performance.A novel welded mask with a total length of 600 mm is presented and shown to be practical for use in the highest heat load front end in the Shanghai synchrotron radiation facility phase-Ⅱ beamline project.展开更多
Different methods of measuring a propagating laser beam quality are summarized.The disadvantages in traditional way in measuring a laser beam quality is analyzed and the insufficiencies of the Shack-Hartmannin method ...Different methods of measuring a propagating laser beam quality are summarized.The disadvantages in traditional way in measuring a laser beam quality is analyzed and the insufficiencies of the Shack-Hartmannin method which is commonly using wave front technique at present is pointed out.Finally,the transmission intensity equation based(TIE-based)measuring way in a laser beam quality evaluation and the corresponding advantages are discussed,which is believed to be a deve-l oping trend in laser beam evaluation.展开更多
基金Supported by 100 Talents Program of The Chinese Academy of Sciences
文摘RF circuit board has a significant impact on performance of the Digital Beam Position Monitor (DBPM) in storage ring of a synchrotron radiation facility.In this paper,a front-end RF board is designed for DBPM,and schematics of the RF board and the test results are given.In view of the inevitable inconsistency in the multi-channel circuit,a calibration circuit is designed to reduce such an influence.The test results show that the calibration method is useful for beam current dependence which is sensitive to channels inconsistency.
基金Supported by National Natural Science Foundaion of China(No.11075198)
文摘In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of radio frequency(RF) front end and high speed data acquisition board.The beam position resolution in the CBPM signal processing system is superior to 1μm.Two signal processing algorithms,fast Fourier transform(FFT) and digital down converter(DDC),are evaluated offline using MATLAB platform,and both can be used to achieve,the CW input signal,position resolutions of 0.31μm and 0.10μm at -16 dBm.The DDC algorithm for its good compatibility is downloaded into the FPGA to realize online measurement,reaching the position resolution of 0.49μm due to truncation error.The whole system works well and the performance meets design target.
文摘Masks are critical elements of synchrotron radiation front end that are exposed to high temperature and stress.The absorber material is typically comprised of dispersion-strengthened copper,which can retain high performance at elevated temperature.Joining processes under vacuum,including brazing and electron beam welding,are novel approaches for prolonging the absorber and for reducing power densities.The mechanical properties of brazed joints and electron beam welded joints of dispersion-strengthened copper workpieces are evaluated by tensile testing at 20,100,and 200 C.The testing results indicate that the tensile strength and elongation of both vacuum joints decrease with increasing temperature.Compared to brazed joints,electron beam welded joints have higher tensile strength,better ductility,and more stable performance.A novel welded mask with a total length of 600 mm is presented and shown to be practical for use in the highest heat load front end in the Shanghai synchrotron radiation facility phase-Ⅱ beamline project.
基金National Basic Research Program of China(973Plan) (No.2010CB327806)National Natural Science Foundation of China(No. 61070165)
文摘Different methods of measuring a propagating laser beam quality are summarized.The disadvantages in traditional way in measuring a laser beam quality is analyzed and the insufficiencies of the Shack-Hartmannin method which is commonly using wave front technique at present is pointed out.Finally,the transmission intensity equation based(TIE-based)measuring way in a laser beam quality evaluation and the corresponding advantages are discussed,which is believed to be a deve-l oping trend in laser beam evaluation.
