07 Accelerator Technology

T16 Pulsed Power Technology

 
Paper Title Page
TUOBFI01 A Diagnostic Kicker System as a Versatile Tool for Storage Ring Characterisations 974
 
  • O. Dressler, J. Feikes, J. Kolbe
    BESSY GmbH, Berlin
 
  For the BESSY II Synchrotron Light Source two diagnostic kicker systems including current pulsers were developed, allowing vertical and horizontal deflection of the stored beam. Synchronised with the revolution trigger, simultaneous pulsing of the systems kicks the stored beam in any transverse direction with a repetition rate of up to 10 Hz allowing a wide range of storage ring investigations. Examples are dynamic aperture measurements and frequency map measurements. Special efforts were made to assure the demands of high amplitude and time stability for this kind of experiments. The technical concept of the systems and the controlling of the measurements are described.  
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THPCH139 Development of an Ion Source via Laser Ablation Plasma 3119
 
  • F. Belloni, D. Doria, A. Lorusso, V. Nassisi
    INFN-Lecce, Lecce
  • L. Torrisi
    INFN/LNS, Catania
 
  Experimental results on the development of a laser ion source (LIS) are reported. LISs are particularly useful in ion accelerators, ion implanters and devices for electromagnetic isotope separation. A focused UV laser beam (0.1 - 1 GW/cm2 power density) was used to produce a plasma plume from a Cu target. Several aspects were investigated: ion angular distribution, energy distribution, ion extraction and charge loss due to ion recombination. Particular attention was devoted to avoid arcs during the extraction phase; it was accomplished by allowing the proper plasma expansion in a suitable chamber before the extraction gap. Diagnostics on free expanding plasma and extracted ions was carried out mainly by time-of-flight measurements, performed by means of Faraday cups and electrostatic spectrometers. At 18kV acceleration voltage, the ion beam current, measured along a drift tube at 147cm from the target, resulted modulated on ion mass-to-charge ratio and its maximum value was 220uA. The Cu+1 ion bunch charge was estimated to be 4.2nC. Ion implantation tests were successfully performed at high acceleration voltage (several tens kV), by using a simple experimental arrangement.  
THPCH140 New Pulsed Current and Voltage Circuits Based on Transmission Lines 3122
 
  • V. Nassisi, F. Belloni, D. Doria, A. Lorusso, M.V. Siciliano, L. Velardi
    INFN-Lecce, Lecce
 
  We present two novel circuits able to compress current or voltage pulse named current compressor circuit (CCC) and voltage compressor circuit (VCC), and two novel amplifier circuits able to double the current or voltage pulse. The compressing circuits were composed by a transmission line, l long and a storage line, l/2 long. The CCC compressed the current pulse by a factor of 2 doubling its intensity, while the VCC compressed the voltage pulse by a factor of 2 doubling its amplitude. The amplifying circuits were composed by a R0 transmission line closed on a set of two parallel or series storage lines which doubled the intensity of the pulses. The current pulse amplifier (CPA) had two R0/2 storage lines in parallel, while the voltage pulse amplifier (VPA) had two 2R0 storage lines in series. The storage line was half long with respect to the input-pulse. In both circuits, one storage line was characterized by an open extremity and the other line by a closed extremity. Connecting the storage lines to suitable load resistors, R0/4, and 4R0 for the CPA and VPA, respectively, a twice of the pulse intensity was obtained. The circuits were studied by computer simulations.  
THPCH143 The Fast Extraction Kicker System in SPS LSS6 3125
 
  • E.H.R. Gaxiola, F. Caspers, L. Ducimetière, P. Faure, T. Kroyer, B. Versolatto, E. Vossenberg
    CERN, Geneva
 
  A new fast extraction has been set up in SPS LSS6 to transfer 450 GeV/c protons as well as ions to Ring 1 of the LHC, via the transfer line TI 2. The system includes four travelling wave kicker magnets, recuperated from earlier installations and upgraded to fit the new application. All four magnets are powered in series, energised by a single PFN generator and terminated by a short circuit. The layout and the modifications to the magnets and the high voltage circuit are described along with the impact of design choices on the performance of the system. Results from laboratory tests and first machine experience are reported on approaches to overcome the effects of the beam induced kicker heating observed earlier, including a beam screen in form of metallic stripes printed directly onto the ferrites and the use of ferrite blocks with high Curie temperature. Prospects for further improvements are briefly discussed.  
THPCH144 The Upgrading of the TLS Injector Bumper and Septum Power Supplies for Top-up Operation 3128
 
  • C.-S. Fann, K.-T. Hsu, S.Y. Hsu, J.-Y. Hwang, K.-K. Lin, K.-B. Liu, Y.-C. Liu
    NSRRC, Hsinchu
 
  Due to the inevitable requirement of routine top-up mode operation at TLS (Taiwan Light Source), the reliability of all components in TLS injector has been reevaluated in the past several months. Among all possible subsystems to be reinforced, the bumper and septum power supplies revealed urgent need of upgrading while operated continuously in the user shifts. In this report, the modification of the charging mechanism of the pulsed power supplies is described. The modular feature of the newly built units provides fast replacement capability in case of components failure. The unified specifications for all components have greatly reduced the effort in preparing spare parts. The test results of these units are presented in this report.  
THPCH146 Solid State Modulators for the International Linear Collider (ILC) 3131
 
  • M.A. Kempkes, N. Butler, J.A. Casey, M.P.J. Gaudreau, I. Roth
    Diversified Technologies, Inc., Bedford
 
  Diversified Technologies, Inc. (DTI) is developing two solid-state modulator designs for the International Linear Collider with SBIR funding from the U.S. Department of Energy. This paper will discuss design tradeoffs, energy storage requirements and alternatives, and the construction and test status of both ILC designs. The first design is a 150 kV hard switch, employing an innovative energy storage system, which must provide 25 kJ per pulse at very tight voltage regulation over the 1.5 millisecond pulse. DTI's design uses a quasi-resonant bouncer (with a small auxiliary power supply and switch) to maintain the voltage flattop, eliminating the need for massive capacitor banks. The second design builds upon earlier DTI work for the 500 kV, 500 A NLC modulators. It uses a solid-state Marx bank, with ~10 kV stages, to drive the ILC klystron. Staggered turn-on of the Marx stages provides voltage regulation without the need for large capacitor banks.  
THPCH147 Solid-state High Voltage Pulse Power in the 10-100 Nanosecond Regime 3134
 
  • M.A. Kempkes, F.O. Arntz, N. Butler, J.A. Casey, M.P.J. Gaudreau
    Diversified Technologies, Inc., Bedford
 
  New particle accelerators, with voltages exceeding 50 kV and currents exceeding 1,000 A, require kicker magnet drivers to deliver pulsed power with durations in the 10-100 ns range. Similar levels of pulse performance are needed for state-of-the-art eximer laser systems, impulse radar transmitters, and particle accelerators for medical therapy. In addition, the processing of food using pulsed electric fields (PEF processing) has similar requirements. In this paper, DTI will review solid-state pulse power technologies capable of delivering high-voltage, high-current pulses with 10-to-100 nanosecond pulse duration. IGBTs, MOSFETs, snap-off diodes, and magnetic pulse compression will be discussed. Current research at Diversified Technologies, Inc. is exploring the impact of these switching devices and circuits on pulse wave shape, pulse repeatability, adjustability of pulse voltage, current and timing, maximum pulse rate (PRF), jitter, and robustness.  
THPCH148 Tests of a High Voltage Pulser for ILC Damping Ring Kickers 3137
 
  • M.A. Palmer, G. Dugan, D. L. Rubin
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • R. Meller
    Cornell University, Department of Physics, Ithaca, New York
 
  The baseline configuration for the International Linear Collider (ILC) damping rings specifies a single 6 km damping ring for electrons and two 6 km rings for positrons. Kicker requirements are determined by the damping ring circumference and the train structure in the main linac. The nominal bunch train parameters in the ILC main linac are trains of 2820 bunches with 308 ns spacing and a train repetition rate of 5 Hz. This means that the pulsers for the damping ring kickers must have rise and fall times suitable for bunch spacings of ~6 ns, must be able to operate with 3.25 Mhz bursts, and must support an average pulse rate of 14.1 kHz. We describe bench and beam tests of a pulser based on fast ionization dynistor technology whose specifications roughly meet these requirements. We then discuss the implications of our results for the ILC damping ring kickers.  
THPCH149 Active RF Pulse Compression using Electrically Controlled Semiconductor Switches 3140
 
  • J. Guo, S.G. Tantawi
    SLAC, Menlo Park, California
 
  In this paper, we present the recent results of our research on the ultra-high power fast silicon RF switch and its application on active X-Band RF pulse compression systems. This switch is composed of a group of PIN diodes on a high purity silicon wafer. The wafer is inserted into a cylindrical waveguide operating in the T·1001 mode. Switching is performed by injecting carriers into the bulk silicon through a high current pulse. Our current design uses a CMOS compatible process and the fabrication is accomplished at SNF (Stanford Nanofabrication Facility). The RF energy is stored in a room-temperature, high-Q 400 ns delay line; it is then extracted out of the line in a short time using the switch. The pulse compression system has achieved a gain of 11, which is the ratio between output and input power. Power handling capability of the switch is estimated at the level of 10MW.