| Paper | Title | Other Keywords | Page |
|---|---|---|---|
| MOEPPB005 | Initial Commissioning of NDCX-II | diagnostics, solenoid, ion, beam-transport | 85 |
|
|||
|
Funding: This work was performed under the auspices of the U.S Department of Energy by LLNL under contract DE AC52 07NA27344, and by LBNL under contract. DE-AC02-05CH11231. The Neutralized Drift Compression Experiment-II (NDCX-II) will generate ion beam pulses for studies of Warm Dense Matter and heavy-ion-driven Inertial Fusion Energy. The machine will accelerate 20-50 nC of Li+ to 1.2-3 MeV energy, starting from a 10.9-cm alumino-silicate ion source. At the end of the accelerator the ions are focused to a sub-mm spot size onto a thin foil (planar) target. The pulse duration is compressed from ~500 ns at the source to sub-ns at the target following beam transport in a neutralizing plasma. We first describe the injector, accelerator, transport, final focus and diagnostic facilities. We then report on the results of early commissioning studies that characterize beam quality and beam transport, acceleration waveform shaping and beam current evolution. We present WARP simulation results to benchmark against the experimental measurements. |
|||
| MOPPR006 | Surface Waves for Testing of Beam Instrumentation | instrumentation, impedance, resonance, electromagnetic-fields | 780 |
|
|||
| The fundamental TM wave can be guided as a surface wave along a single dielectric coated wire. Such a setup is known as a Goubau line. Close to the wire the TM wave resembles closely the radial electric and azimuthal magnetic fields of a charged particle beam moving in an accelerator. Hence, it can be used to test beam instrumentation in the workshop. We introduce the principle, discuss benefits, and compare measurements of a beam instrumentation device performed with a Goubau line to measurements performed with a standard bench testing setup. | |||
| WEPPC091 | A Path to Higher Q0 with Large Grain Niobium Cavities | cavity, SRF, niobium, accelerating-gradient | 2426 |
|
|||
|
The improvement of the quality factor Q0 of superconducting radio-frequency (SRF) cavities at medium accelerating gradients (~ 20 MV/m) is important in order to reduce the cryogenic losses in continuous wave accelerators for a variety of applications. In recent years, SRF cavities fabricated from ingot niobium have become a viable alternative to standard high-purity fine-grain Nb for the fabrication of high-performing SRF cavities with the possibility of significant cost reduction. Initial studies*,**, demonstrated the improvement of Q0 at medium field in cavities heat treated at 800-1000 °C without subsequent chemical etching. To further explore this treatment procedure, a new induction furnace with an all-niobium hot-zone was commissioned. A single-cell 1.5 GHz cavity fabricated from ingot material from CBMM, Brazil, with RRR~200, was heat treated with the new furnace in the temperature range 600-1400 °C for several hours. Residual resistance values below 5 nano Ω have been consistently achieved on this cavity as well as Q0 values above 4.5×1010 at 2 K and 100 mT peak surface magnetic field. Q0-values of the order of 1011 have been measured at 1.5 K.
* G. Ciovati, et al., Phys. Rev. ST Accel. Beams 13, 022002 (2010). ** G. Ciovati, et al., Proc. of the 15th Int. Conf. on RF Superconductivity, Chicago, July 25-29, 2011, paper TUPO051 |
|||
| THPPD053 | Study on Eddy Current Power Losses in Insulated Core Transformer Primary Coil | power-supply, high-voltage, factory, simulation | 3632 |
|
|||
| Insulated core transformer (ICT) high-voltage DC power supply is widely used in electron beam accelerator. With air gap in ICT, the reluctance of magnetic circuit is larger than other transformers, and the transverse magnetic flux leakage around the primary coil is more serious. Because the magnetic flux on the radial direction of coil cannot be ignored, the eddy current loss on the wire should be discussed. In this paper, simulation and analysis of the eddy current loss is presented. The relationship between the sizes of the coil wire is also discussed. An optimal design of the primary coil is shown. | |||
| THPPD071 | A Compact Switching Power Supply utilizing SiC-JFET for the Digital Accelerator | power-supply, simulation, synchrotron, acceleration | 3677 |
|
|||
|
New induction synchrotron system using an induction cell has been developed and constructed at KEK*. We refer to the accelerator using the induction acceleration system combined with digitally controlled PWM power supply as Digital Accelerator**. In that system, the switching power supply is one of the key devices which realize digital acceleration. The requirements of the switching power supply are high voltage (2 kV) and high repetition frequency (1 MHz). In the present system, we used series connected MOSFETs as the switching device. However, series connection gives large complexity and less reliability. Among the various switching devices, a SiC-JFET is the promising candidates because it has ultrafast switching speed and voltage blocking capability. Therefore, we have developed a new device to substitute existing silicon MOSFET and succeeded to operate with 1 MHz – 1 kV – 27 A condition***. Then we designed and constructed a ultra compact full bridge switching power supply utilizing those devices as a next step. Design and test results will be presented in the conference.
* T. Iwashita et al., KEK Digital Accelerator, Phys. Rev. ST-AB 14, 071302 (2011) ** K. Takayama et al., in Proc. of IPAC’11, pp 1920-1922 *** K. Okamura et al., in Proc. of IPAC’11, pp 3400-3402 |
|||
| THPPD072 | Performance Optimization of the Stacked-Blumlein | simulation, coupling, impedance, high-voltage | 3680 |
|
|||
|
Funding: This work was supported by the National Natural Science Foundation of China (11035004) For the applications of the Dielectric Wall Accelerator (DWA), the stacked Blumlein pulse generator comprised of parallel-plate transmission lines is being developed. The peak output voltage of the stacked Blumlein will be much lower than expected due to the parasitic coupling among the individual pulse forming lines of the Blumlein stack. The finite difference time domain method is used to model the stacked Blumlein structure and determine the outputs. We present the optimization of a 20-Blumleins-stack in this paper. The results for different structures are discussed. |
|||
| THPPP039 | Simulations for a Buncher-Cavity at GSI | simulation, cavity, impedance, resonance | 3821 |
|
|||
| Buncher cavities can be used to bunch and rebunch or re-accelerate particle beams. A special form of these buncher cavities is a spiral structure. one of its main features is the easy adjustable frequency. A two-gap structure for the GSI has been simulated and will be build at the University of Frankfurt. This structure shall replace an existing buncher at GSI. It is designed to an frequency of 36 MHz. Also general simulations of spiral bunchers will be presented. | |||
| THPPR025 | Operational Efficiency of the AIRIX Accelerator Since its Commissioning | electron, high-voltage, site, vacuum | 4017 |
|
|||
| AIRIX is a high current (19 MeV, 2 kA) electron linear induction accelerator used as a 60 ns single shot X-ray source for hydrodynamic experiments. As single shot experiments are performed, the best performances and a high reliability level must be met for each experiment. This accelerator has been running for hydroshot experiments since 2000 and several thousands electron and X-ray beams have been produced so far. The functioning time of the AIRIX machine in the CEA/Moronvilliers test site is now coming to its end. From mid-2012, it will be then refurbished, dismounted and moved to another CEA test site. This paper draws up the report of AIRIX operations over this long eleven-year period. Maintenance policy, relative cost efficiency, reliability and performance results of the AIRIX accelerator over this period are dealt with and discussed. | |||