Author: Jia, Q.K.
Paper Title Page
MOPFI038 Generation and Measurement of Sub-picosecond Electron Bunch in Photocathode RF Gun 372
  • W.W. Li, Z.G. He, R. Huang, Q.K. Jia, G. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  The generation of subpicosecond electron bunch in the photocathode rf gun was considered and simulated by improving the acceleration gradient of the gun, suitably tuning the charge of the electron bunch and the acceleration phase. To measure the length of the electron bunch, the design of a nondestructive bunch length measurement technology was also presented in this paper.  
MOPFI039 The Design of a Compact THz Source Based on Photocathode RF Gun 375
  • W.W. Li, Z.G. He, R. Huang, Q.K. Jia
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  Narrow-band THz coherent Cherenkov radiation can be driven by a subpicosecond electron bunch traveling along the axis of a hollow cylindrical dielectric-lined waveguide. We present a scheme of compact THz radiation source based on the photocathode rf gun. On the basis of our analytic result, the subpicosecond electron bunch with high charge (800pC) can be generated directly in the photocathode rf gun. A narrow emission spectrum peaked at 0.24 THz with 2 megawatt (MW) peak power is expected to gain in the proposed scheme (the length of the facility is about 1.2 m), according to the analytical and simulated results.  
TUPEA028 Echo-enabled Harmonic Generation based on Hefei Storage Ring 1208
  • H.T. Li, W.W. Gao, Q.K. Jia, L. Wang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  Echo-Enabled Harmonic Generation (EEHG) has been proposed and experimently demonstrated recently. In this paper, we numerically investigate the possibility of operating EEHG based on Hefei storage ring, which has a short circumference and a small momentum compaction factor. The difference to other similar reserch is that we use the whole ring as the first dispersive section and an optical klystron as the second one.  
WEPWA022 The Fabrication and Measurement of the New Insertion Devices of Hefei Light Source 2177
  • Q.K. Jia
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  To meet the requirements of users for higher brilliance and good transverse coherence VUV and soft X-ray synchrotron radiation, Hefei Light Source(HLS) will be upgraded. After upgrade HLS will have smaller beam emittance and install more new insertion devices. The new insertion devices include one elliptically polarizing undulator with 104 mm period, one in-vacuum undulator with 40mm period, one wiggler with 152mm period and one quasi-periodic undulator based on a new scheme proposed by us. In this paper the fabrication and the preliminary results of the magnetic field measurements of the new insertion devices are reported.  
WEPEA025 Chromatic Sextupole Pair Optimization Methods for Enlarging Dynamic Aperture 2555
  • Z. Bai, Q.K. Jia, W. Li, L. Wang, Q. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  Based on the step-by-step chromaticity compensation method [1] and artificial intelligence algorithms, we propose new numerical methods, called chromatic sextupole pair optimization methods, for enlarging the dynamic aperture of electron storage rings. In the new methods, the decision variables related to chromatic sextupole pairs are optimized using artificial intelligence algorithms to enlarge the dynamic aperture. We demonstrate that the new methods are equivalent to the recently used numerical method, in which the decision variables, sextupole strengths, are optimized using artificial intelligence algorithms.
[1] E. Levichev, P. Piminov, Proceedings of EPAC 2006, p. 2116.