| Paper | Title | Other Keywords | Page |
|---|---|---|---|
| MOPC02 | Improvement of Termination Field of Bulk HTSC Staggered Array Undulator | undulator, electron, simulation, controls | 96 |
|
|||
|
We have proposed a bulk High Temperature Superconductor Staggered Array Undulator (Bulk HTSC SAU) to achieve higher undulator field, shorter period, and variable K-value without changing gap[1]. The purpose of this study is to revise the controversial point, that bulk HTSC SAU generates strong wicked magnetic field on its terminations, which scatters electron beam. Therefore we studied a new method to correct the field. We developed a physical model which based on Bean model to deal with the bulk superconducting material and then constructed a simulation code. By using the calculation results, we developed the correction method by adding bulk material on the edge of undulator. Measurement of the magnetic field of a prototype of bulk HTSC SAU with this method has been performed. We confirm that the numerical calculation well describe the experimental results. In this conference, numerical and experimental results of our end field termination method will be presented.
[1] R. Kinjyo, T. Kii, H. Zen, K Higashimura, K Masuda, K. Nagasaki, H. Ohgaki, Y.U. Jeong "Bulk High-TC Super Conductor Staggered Array Undulator" Proceedings of FEL2008 |
|||
| WEPA01 | Commissioning of a Photoinjector in HLS | laser, cathode, emittance, gun | 331 |
|
|||
| A BNL type photoinjector was installed in HLS (Hefei Light Source) and commissioning work was carrying out in last months. The dark current was measured when the high power testing of the gun was processed. The quantum efficiency (QE) of the photocathode was measured and studied, the main parameters of beam quality such as electric charge, transverse emittance and energy were measured and presented in this paper. | |||
| WEPA21 | Research of Emittance Compensation of CAEP CW DC-Gun Photoinjector | emittance, gun, space-charge, electron | 377 |
|
|||
| Emittance growth is very import for photo-cathode injector due to space charge effect. The emittance compensation technology will be used on the 350 kV photo-cathode DC gun for the CAEP CW FEL, where the energy of electron beam is extremely low and Emittance growth is great severity. In this paper, the space charge force and its effect on electron beam transverse emittance is discussed, the principle of emittance compensation in phase space is analyzed. And a solenoid for emittance compensation is designed. Its beam dynamics has been studied by the PARMELA code. Simulation results indicate that the normalized transverse RMS emittance for electron beam of 80 pC is 1.267 mm•mrad with σr=1.5 mm, σz=4.25 pS. | |||
| WEPB19 | Enhancement of Undulator Field in Bulk HTSC Staggered Array Undulator with Hybrid Configuration | undulator, synchrotron, radiation, ion | 424 |
|
|||
|
Funding: This work was supported by the Grant-in-Aid for Scientific Research B and JSPS Fellows by the Ministry of Education, Culture, Sports, Science and Technology of Japan The purpose of this study is enhancement of the undulator field and it's stability in bulk high temperature superconductor staggered array undulator by introducing hybrid configuration. The authors made the magnetic field calculations with some hybrid configurations consists of bulk HTSCs, ferromagnetic pieces and permanent magnets. We also made prototype measurements. The results shows the hybrid configuration can generates stronger and more uniform magnetic field than bulk-HTSCs-only configuration. In this conference, numerical and experimental results of the hybrid configuration will be presented. |
|||
| THPA19 | Photocathodes at FLASH | cathode, gun, laser, electron | 511 |
|
|||
| For several years now, caesium telluride photocathodes are successfully used in the photoinjector of the free electron laser FLASH at DESY, Germany. They show a high quantum efficiency and long lifetime. The injector produces routinely thousand of bunches per second with a single bunch charge in the range of 0.1 to 1.5 nC. Recent results on lifetime, quantum efficiency, darkcurrent, and operating experience is reported. At DESY, a new preparation system has been set-up. First cathodes have been produced and tested successfully. | |||
| THPB02 | Implementation of 2D-emittance Compensation Scheme in the BERLinPro Injector | emittance, space-charge, booster, linac | 564 |
|
|||
|
Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. High power ERL based FELs demand low emittance, high peak and average current beams. The injection energy in an ERL is usually rather low to decrease power consumption and avoid activation of the beam dump. Therefore, the space charge is the main reason of the emittance degradation in the injector. The implementation of an emittance compensation scheme in the injector is necessary to achieve a low emittance. Since injector’s optics is axially non-symmetric, the 2D-emittance compensation scheme [1] should be used. The implementation of the 2D-emittance compensation scheme at BERLinPro injector is presented in this contribution. Other sources of emittance growth in ERL injectors are also discussed.
[1] S.V. Miginsky, "Emittance compensation of elliptical beam", NIM A 603 (2009), pp 32-34. |
|||
| THPB05 | Modeling of the Beam Break Up Instability in Berlin Energy Recovery Linac Project | linac, cavity, optics, HOM | 568 |
|
|||
| Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current low emittance beam. The conversion efficiency of an FEL is about 1% therefore superconducting ERL-based FEL machines look promising. One of the problems of superconducting ERL machines is the Beam Break Up (BBU) instability which limits the current. In this work the threshold current of the BBU instability was calculated for the BERLinPro. The comparison of two 100 MeV linacs based on different type of superconducting cavities is made. Different methods of BBU suppression are investigated (e.g. the influence of solenoid, pseudo-reflector and quadruple triplets in the linac structure on the BBU threshold). | |||
| THPB29 | Design of a Low Emittance and High Repetition Rate S-band Photoinjector | gun, emittance, cathode, laser | 621 |
|
|||
| One of key components for the success of X-ray free-electron lasers (FELs) is the electron injector. Injectors starting with photocathode RF guns provide exceptionally high brightness electron beams and therefore they are being adopted as injectors of X-ray FELs. In this paper we show how to improve the photoinjector performance in terms of emittance and repetition rate by means of components optimization based on mature technologies. Transverse emittance at an injector is reduced by optimizing the RF gun cavity design, gun solenoid position, and accelerating section position. The repetition rate of an injector mainly depends on the cooling capability of the gun cavity. By adopting the coaxial RF gun coupler and improving cooling-water channels of the gun, a maximum repetition rate of 1 kHz for the injector will be achieved. | |||