TY - CONF AU - Li, C.L. AU - Chao, A. AU - Feng, C. AU - Jiang, B.C. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Lattice Design for the Reversible SSMB J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1507 EP - 1509 KW - radiation KW - electron KW - emittance KW - storage-ring KW - bunching DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPGW045 UR - http://jacow.org/ipac2019/papers/tupgw045.pdf ER - TY - CONF AU - D'Auria, G. AU - Aicheler, M. AU - Aksoy, A.A. AU - Alesini, D. AU - Apsimon, R. AU - Arnesano, J.M. AU - Bellaveglia, M. AU - Bernhard, A. AU - Bosco, F. AU - Buonomo, B. AU - Burt, G. AU - Calvi, M. AU - Cardelli, F. AU - Castaneda Cortes, H.M. AU - Castilla, A. AU - Clarke, J.A. AU - Croia, M. AU - Cross, A.W. AU - Dattoli, G. AU - Di Mitri, S. AU - Diomede, M. AU - Dowd, R.T. AU - Dunning, D.J. AU - Fang, W.D. AU - Faus-Golfe, A. AU - Ferrario, M. AU - Ficcadenti, L. AU - Gallo, A. AU - Gazis, E.N. AU - Gazis, N. AU - Geometrante, R. AU - Gethmann, J. AU - Giribono, A. AU - Goryashko, V.A. AU - Han, Y. AU - Jacewicz, M. AU - Janssen, X.J.A. AU - Kokole, M. AU - Latina, A. AU - Liu, X. AU - Luiten, O.J. AU - Marcos, J. AU - Marín, E. AU - Mostacci, A. AU - Mutsaers, P.H.A. AU - Muñoz Horta, R. AU - Nguyen, F. AU - Palumbo, L. AU - Petralia, A. AU - Piersanti, L. AU - Priem, J.M.A. AU - Pérez, F. AU - Rochow, R.A. AU - Rossi, C. AU - Ruber, R.J.M.Y. AU - Schmidt, T. AU - Schulte, D. AU - Spataro, B. AU - Stapnes, S. AU - Stragier, X.F.D. AU - Taylor, G. AU - Thompson, N. AU - Vaccarezza, C. AU - Wu, X.W. AU - Wuensch, W. AU - Zhang, K. AU - Zhang, L. AU - Zhu, D. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The CompactLight Design Study Project J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The H₂020 CompactLight Project (www. CompactLight.eu) aims at designing the next generation of compact X-rays Free-Electron Lasers, relying on very high gradient accelerating structures (X-band, 12 GHz), the most advanced concepts for bright electron photo injectors, and innovative compact short-period undulators. Compared to existing facilities, the proposed facility will benefit from a lower electron beam energy, due to the enhanced undulators performance, and will be significantly more compact, with a smaller footprint,  as a consequence of the lower energy and the high-gradient X-band structures. In addition, the whole infrastructure will also have a lower electrical power demand as well as lower construction and running costs. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1756 EP - 1759 KW - FEL KW - linac KW - electron KW - undulator KW - brightness DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB032 UR - http://jacow.org/ipac2019/papers/tuprb032.pdf ER - TY - CONF AU - Li, C.L. AU - Chen, J.H. AU - Chen, Z.C. AU - Liu, B. AU - Liu, T. AU - Wang, X.T. AU - Wu, H.L. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Second Order Intensity Correlation and Statistical Properties of a Soft X-Ray Free Electron Laser J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - High degree of transverse field coherence is one of the unique properties of an FEL compared with a 3rd gen-eration storage ring light source. As a result, the FEL advances the development of innovative research and technology that was not previously feasible. A truly coherent source should be coherent in all orders de-scribed from the intensity correlation functions. In this paper, second order intensity correlation of FEL radia-tion is investigated based on the Hanbury Brown-Twiss intensity correlation method. The statistical properties of radiation produced from SASE was also investigated and compared with the statistical proper-ties of a phase-locked laser. The results show that the statistical properties of a SASE mode behave as a cha-otic source, which is significantly different from the properties of a phase-locked laser beam. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1788 EP - 1791 KW - laser KW - FEL KW - radiation KW - electron KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB046 UR - http://jacow.org/ipac2019/papers/tuprb046.pdf ER - TY - CONF AU - Wang, Z. AU - Gu, Q. AU - Wang, G.L. AU - Zhao, M.H. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Injector Physics Design at SHINE J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - As a CW x-ray free electron laser facility, SHINE has a high requirement on the electron beam quality in the linac, as well as in the injector. SHINE injector consists of a 162.5 MHz normal conducting VHF gun, a NC 1.3 GHz RF buncher, a one cavity SC cryomodule, an eight cavity SC cryomodule and 3 solenoids along the injector layout. Some beam diagnostic element are inserted in the layout as well. In this paper, we try to introduce the injector physics design at shine. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1801 EP - 1803 KW - laser KW - electron KW - feedback KW - FEL KW - emittance DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB053 UR - http://jacow.org/ipac2019/papers/tuprb053.pdf ER - TY - CONF AU - Zeng, L. AU - Deng, H.X. AU - Feng, C. AU - Gu, D. AU - Liu, B. AU - Wang, G.L. AU - Zhao, Z.T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The Beam-Based Alignment Simulation and Preliminary Experiment at SXFEL J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Shanghai soft X-ray Free-electron Laser facility (SXFEL) is now serving as an experimental platform for fundamental free-electron laser (FEL) principle tests. The machine puts very tight tolerance on the straightness of the electron beam orbit. It is hard to achieve the required trajectory due to the off-axis field of the misaligned quadrupoles and undulator segments especially for the SXFEL driven by low energy linac (840MeV). This tight requirement on electron beam straightness can only be met through the beam-based alignment (BBA) technology which achieved great success at LCLS, PAL-XFEL, European-XFEL and SCALA with high electron beam energies. But there has been no report about satisfactory BBA experiment results on soft X-ray FEL facility driven by relatively low energy linacs (on the order of 2 GeV or less) up to now. Here, we report the simulation results and preparatory experiment progress of the BBA at SXFEL with the method of dispersion-free steering (DFS). The experiment results show some improvements of the electron beam orbit and the phenomenon of the dispersion-free. The entire BBA experiment and a feedback system of electron beam trajectory may also be included. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1804 EP - 1807 KW - electron KW - FEL KW - alignment KW - quadrupole KW - undulator DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB054 UR - http://jacow.org/ipac2019/papers/tuprb054.pdf ER - TY - CONF AU - Yu, C. AU - Deng, H.X. AU - He, Y.Z. AU - Hu, X. AU - Jiang, Z. AU - Liu, B. AU - Qian, M.F. AU - Wang, D. AU - Wang, H.F. AU - Wen, Y.M. AU - Xiang, S. AU - Yin, L. AU - Zhang, J.D. AU - Zhang, W. AU - Zhao, Z.T. AU - Zhou, Q.G. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - First Results of the IVU16 Prototype Undulator Measurements J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Shanghai Synchrotron Radiation Facility (SSRF) has developed a 16 mm period length, 4 mm gap, in-vacuum undulator (IVU) that is planned to be installed and tested in the 1.5 GeV SXFEL-SBP beam line. This paper will describe the main parameters of the undulator and the key design choices that have been made. The first undulator prototype was assembled and magnetically tested. First measurements with vacuum chamber will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1808 EP - 1810 KW - FEL KW - vacuum KW - undulator KW - MMI KW - SRF DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB055 UR - http://jacow.org/ipac2019/papers/tuprb055.pdf ER - TY - CONF AU - Zhao, Y.B. AU - Chang, Q. AU - Xu, K. AU - Zhang, Zh.G. AU - Zhao, S.J. AU - Zheng, X. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Solid State Amplifier of SC Linac for Shine J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Shanghai HIgh repetition rate XFEL aNd Extreme light facility （SHINE）is a platform for technique and science research which energy is 8GeV, operated in CW-mode and beam current is 0.2mA. It include a LINAC of 8GeV, three undulator lines, three beam lines and ten experiment stations. SHINE is located underground 30 meters. The lengths of facility is 3kM and the length of LINAC is 1.2km. The acceleration architecture of LINAC consists of six hundred 1.3GHz and sixteen 3.9GHz TELSA type cavities. The 5.2kW SSA will drive the 1.3GHz superconductive cavities and 2kW SSA will power the 3.9GHz superconductive cavities. Four 1.3GHz prototypes of SSA have already been produced, the design and performance are showed in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1814 EP - 1816 KW - cavity KW - linac KW - LLRF KW - hardware KW - factory DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB059 UR - http://jacow.org/ipac2019/papers/tuprb059.pdf ER - TY - CONF AU - Wang, L. AU - Fang, W. AU - Hirshfield, J.L. AU - Jiang, Y. AU - Shchelkunov, S.V. AU - Zhao, Z.T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - 1st+2nd Harmonic Photocathode Bimodal Gun R&D J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A novel Bimodal Electron Gun is designed to apply microwaves at two harmonically-related frequency in a 0.6 cell RF gun to increase the RF breakdown threshold and enhance the beam quality. This stratagem is intended to allow the RF gun structure to support a high accelera-tion gradient as well as to manipulate the emittance evolution in the half cell. By selecting a proper ampli-tude ratio and phase relationship between the first and second harmonic RF field components in the gun cavity, the superposition of the harmonic field components can provide a flat-top like RF profile to omitting the RF emittance component in the gun, while increase the RF breakdown threshold. The recent status of the Bimodal Electron Gun R&D is presented, including the designs of the novel two frequency RF structure and the simulation of the beam dynamic. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2054 EP - 2057 KW - gun KW - emittance KW - cathode KW - electron KW - cavity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS054 UR - http://jacow.org/ipac2019/papers/tupts054.pdf ER - TY - CONF AU - Fang, W. AU - Wang, L. AU - Zhao, Z.T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design Study of 3.6-cell C-band Photocathode Electron Gun J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A C-band photocathode injector composed of a 3.6-cell C-band photocathode RF gun and two 1.8-meter C-band accelerating structures is proposed. The injector is a low emittance electron source for Free Electron Lasers (FEL) and other compact light sources. The RF structure of the cavities is designed with 2D SUPERFISH simulation. The Beam dynamic study in ASTRA helps rectify the 2D RF simulation. To feed the cavities, a design of extra coaxial coupler with RF gun structure is presented. With compact focusing solenoids, for 0.25nC bunch charge, the final energy can reach 6.9 MeV energy and the 95% emittance can be as low as 0.23 mm mrad (95%). All the details of RF design and beam dynamics studies are presented in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2121 EP - 2123 KW - gun KW - emittance KW - simulation KW - FEL KW - cathode DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS085 UR - http://jacow.org/ipac2019/papers/tupts085.pdf ER - TY - CONF AU - Gao, B. AU - Leng, Y.B. AU - Xu, X.Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Deep Learning Applied for Multi-Slit Imaging Based Beam Size Monitor J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In order to satisfy the requirement of high speed measurement and improve the accuracy of BSM (beam size monitor), multi-slit imaging based BSM has been proposed by SSRF at 2017. However, it is very difficult to deconvolve the image and figure out the beam size, which requires dedicated algorithms to solve this issue. Deep learning is one of the most popular algorithms, which can learn to mimic any distribution of data. In the region of Beam instrumentation, they can be taught to deal with many difficult problem. In this paper, multi-layer neural network is used to process the images from the multi-slit imaging system. Training processes, struct of the neural networks and the result of the experiments will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2587 EP - 2590 KW - network KW - simulation KW - SRF KW - synchrotron KW - synchrotron-radiation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW049 UR - http://jacow.org/ipac2019/papers/wepgw049.pdf ER - TY - CONF AU - Wu, T. AU - Cao, S.S. AU - Chen, J. AU - Gao, B. AU - Lai, L.W. AU - Leng, Y.B. AU - Zhou, Y.M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design of Stripline BPM for the SHINE Project J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - As a under-constrution forth-generation light source in China, SHINE(Shanghai HIgh repetition rate XFEL aNd Extreme light facility) is expected to play an important role in basic scientific research in the field of materials and medicine. However, the performance of FEL depends critically on the completeness and quality of their beam diagnostic systems. Since the SHINE project will operate with bunch charge at 100pC, which is only one-quarter of that in the SXFEL, the measurement accuracy requirements for SBPM will increase significantly. On the other hand, the bunch repetition frequency of SHINE reached 1MHz, which shortened the threshold for measuring dead time. Fitting the requirement, the passband and the sampling rate design of stripline BPM is upgraded for the SHINE project. The final design was simulated using the data on the SXFEL, and the some inspiring results have been made. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2605 EP - 2607 KW - FEL KW - simulation KW - experiment KW - diagnostics KW - beam-diagnostic DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW057 UR - http://jacow.org/ipac2019/papers/wepgw057.pdf ER - TY - CONF AU - Xu, X.Y. AU - Leng, Y.B. AU - Zhou, Y.M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Machine Learning Application in Bunch Longitudinal Phase Measurement J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - High resolution bunch-by-bunch longitudinal phase measurement has been realized at Shanghai Synchrotron Radiation Facility (SSRF). In order to fully exploit the potency of the bunch phase monitor, the transient state during injection is being further studied. A longitudinal phase fitting method was used to study the synchrotron damping oscillation in injection events, where we can get the energy offsets between the injector and the storage ring, refilled bunch arrived time and the synchrotron damping time. However, manual multi-parameter fitting of nonlinear functions is awfully complex and slow. Machine learning algorithms, such as gradient descent and artificial neural network (ANN) is more suitable to do this fitting. Through these methods, we can quickly obtain more accurate fitting parameters and further realize online measurement of the refilled charge arrived time, energy offsets between the injector and storage ring, and the synchrotron damping time. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2625 EP - 2628 KW - network KW - synchrotron KW - damping KW - SRF KW - injection DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW064 UR - http://jacow.org/ipac2019/papers/wepgw064.pdf ER - TY - CONF AU - Li, Z.B. AU - Fang, W. AU - Gu, Q. AU - Huang, X.X. AU - Tan, J.H. AU - Zhao, Z.T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - High Power Test of the First C-band Spherical Pulse Compressor Prototype J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Recently, a new C-band (5712 MHz) compact spherical radio frequency (RF) pulse compressor was designed and tested for Shanghai Soft X-ray Free Electron Laser Facili-ty (SXFEL). This pulse compressor utilizes one high Q₀ spherical RF resonant cavity that works with two TE1, 1,3 modes and a dual-mode polarized coupler. The peak power multiply factor is 6.1 and average power gain 3.8 in theory. During the high power test, a peak power mul-tiply factor of 5.74 and average power gain of 3.77 was achieved. This paper presents the RF measurement of the C-band spherical pulse compressor and the high power test results. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2896 EP - 2898 KW - GUI KW - cavity KW - FEL KW - electron KW - linac DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPRB042 UR - http://jacow.org/ipac2019/papers/weprb042.pdf ER - TY - CONF AU - Qiao, J. AU - Pu, Y.H. AU - Xie, X.C. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The Beam Dynamics Design of the Proton Synchrotron Linear Injector for Proton Therapy J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A compact room-temperature injector is designed to accelerate 20 mA proton beam from 30 keV to 7.0 MeV for the purpose of Proton Synchrotron Linear Injector for Proton Therapy. The main feature of this linac injector is that the 4-vane Radio Frequency Quadrupole (RFQ) and the Drift Tube Linac (DTL) section are matched by one triplet and powered by one RF power source. The beam is matched from the first RFQ section to the second DTL section in traverse and longitudinal directions. The overall accelerating gradient of this design has reached up to 1.6 MV/m with transmission efficiency of 96%.This injector combines a 3 m long 4-vane RFQ from 30 keV to 3.0 MeV with a 0.8 m long H-type DTL section to 7.0 MeV. In general, the design meets the requirements of the Pro-ton Synchrotron and the Terminal treatment. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3167 EP - 3169 KW - DTL KW - rfq KW - proton KW - linac KW - cavity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPTS031 UR - http://jacow.org/ipac2019/papers/wepts031.pdf ER - TY - CONF AU - Liu, Y.F. AU - Chen, Z.H. AU - Gu, M. AU - Tong, J. AU - Wu, Y. AU - Yuan, Q. AU - Zhou, X.X. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design a Precise Stability Controller for High Power Pulse Modulator Based on FPGA J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Shanghai Soft X-ray Free Electron Laser (SXFEL) facility is under testing at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences. The stability of RF system is one of the major factors to get great beam performance. It is mainly determined by klystron modulators power supply. The beam voltage of the LINAC klystron modulator, which is the pulsed power source of the RF amplifier, is directly affecting the RF amplitude and phase. This paper shows the suitable upgrade scheme of the modulator power supply and design considerations for the stability improvement of modulator power supply for Shanghai SXFEL. We present a real time feedback control system of LINAC pulse modulator to improve pulse to pulse amplitude stability. The feedback control system is based on the principle of embedded FPGA techniques. The control system consists of an embedded NIOS II processor, a High resolution ADC and an upper computer. The NIOS II processor manage on chip FIFO, ADC, IRQ, and Ethernet. The relevant experiments indicate that the feedback control strategy reaches required function. It is useful to improve the stability of existing modulator power supply. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3900 EP - 3903 KW - controls KW - FEL KW - FPGA KW - linac KW - experiment DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB041 UR - http://jacow.org/ipac2019/papers/thprb041.pdf ER - TY - CONF AU - Yuan, Q. AU - Gu, M. AU - Liu, Y.F. AU - Tong, J. AU - Wu, Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Stability Research Progress on High-power Pulse Modulator for SXFEL-UF J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Abstract: SXFEL-UF(Shanghai Soft X-ray Free Electron Laser User Facility) under construction presently demands higher energy stability. Stability of pulse modulator feeding power for klystron plays an utmost important role in energy stability and occupy dominant factors in bringing influences in stability of RF power. Presently, stability of high-power pulse modulator of LINAC (Linear Accelerator) is on the level of 0.1% to 0.05% usually. In order to meet the higher stability requirements, it is very necessary for close-loop feedback control techniques instead of traditional open-loop to be applied in the modulator design. The stability controller adopts double control-loops techniques which feedback signals are respectively from PFN(Pulse Forming Network) and pulse transformer in oil tank. In addition, the paper also introduces recent progress on high stability CCPS research(Capacitor Charging Power Supply), which brings direct impact on the stability of modulator. In comparison with the former close-loop design, high stability CCPS design takes the overall modulator stability into full consideration. And the feedback control algorithm utilized to adjust PWMs for full bridge switch is implemented in the CCPS controller directly rather than modulator controller independent of CCPS. It is expected to obtain 0.01% stability by taking the above measures. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3904 EP - 3907 KW - controls KW - feedback KW - FEL KW - FPGA KW - network DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB042 UR - http://jacow.org/ipac2019/papers/thprb042.pdf ER - TY - CONF AU - Tong, J. AU - Gu, M. AU - Liu, B. AU - Liu, Y.F. AU - Wang, R. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design and Simulation of Thin Eddy-Current Septum for Injection of Diffraction Limited Storage Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Ultra-low emittance in Diffraction Limited Storage Ring (DLSR) usually has small Dynamic Aperture (DA), which makes the traditional off-axis injection inadequate. Fast kickers together with thin septum magnets or direct current lambertsons could support on-axis injection for closely-spaced bunches with small DA. Thin eddy-current septum prototype had been designed for injection with laminated silicon steel sheets as magnet core. Theoretical analysis and transient simulation had been carried out within OPERA software. Due to the minimum thickness of the septa is only 1 mm , several optimization approaches had been applied, such as shielding with strongly paramagnetic material and exciting with full cycle driving pulse, to satisfy the requirement that the leakage field is less than 0.1% with respect to the main one. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3908 EP - 3911 KW - septum KW - injection KW - simulation KW - HOM KW - storage-ring DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB043 UR - http://jacow.org/ipac2019/papers/thprb043.pdf ER - TY - CONF AU - Li, L. AU - Gu, Q. AU - Liu, Y.F. AU - Liu, Y.J. AU - Wang, Z. AU - Xiao, C.C. AU - Zhang, J.Q. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - LLRF Control System for RF GUN at SXFEL Test Facility J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A Soft X-ray Free Electron Laser Test Facility (SXFEL-TF) based on normal conducting linear accelerator was constructed at the Shanghai Synchrotron Radiation Facility (SSRF) campus by a joint team of Shanghai Institute of Applied Physics and Tsinghua University. It consists of multiple Radio Frequency (RF) stations with standing wave cavity (RF Gun) and traveling wave accelerating structures working at different frequencies. Low Level Radio Frequency (LLRF) system is used to measure the RF field in the cavities or structures and correct the fluctuation in RF fields with pulse-to-pulse feedback controllers. This paper describes the hardware and architecture of the LLRF system for electromagnetic filed stabilization inside the radio frequency electron gun, in the SXFEL-TF. A complete control path has be presented, including RF front-end board, I/Q detector and feedback controller. Algorithms used to stabilize the RF field have been presented as well as the software environment used to provide remote access to the control device. Finally, the performance of the LLRF system that was realized in the beam commissioning is presented and meets the high accuracy requirements. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3912 EP - 3914 KW - gun KW - controls KW - LLRF KW - FEL KW - FPGA DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB044 UR - http://jacow.org/ipac2019/papers/thprb044.pdf ER - TY - CONF AU - Liu, K. AU - Gu, Q. AU - Li, L. AU - Wang, Ch. AU - Zhao, M.H. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - MODELING AND SIMULATION FOR MULTI-FEEDING CAVITY WITHOUT BEAM LOADING J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Multi-feeding cavity usually be applied in super-conducting and normal-conducting RF cavity. The differences between multiple input couplers in coupler coefficient, incident power and phase will cause the cavity field stabilities can not meet the requirements. For explore the influences of these differences and develop equations for measurement, a multi-feeding LCR transient model was developed. As two-feeding cavity, the VHF photocathode electron gun was model and simulated in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3921 EP - 3923 KW - cavity KW - electron KW - impedance KW - simulation KW - beam-loading DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB049 UR - http://jacow.org/ipac2019/papers/thprb049.pdf ER -