Summary form only given: A 600 kV, 150 ns rise-time pulse transformer with a 1:15 step-up ratio has been developed for klystron pulse modulators. This pulse transformer has been designed to produce ...pulses with a peak current of 1200 A, a peak voltage of 600 kV, a rise-time of 150 ns, a flat-top width of 400 ns, and a repetition rate of 50 pps. To realize a fast rise-time, the pulse transformer with a low stray capacitance and leakage inductance should be designed. One-turn primary winding as well as a bililer and tapered secondary winding design was adapted to minimize the leakage inductance. Additionally, amorphous alloy toroidal cores with a high magnetic flux swing and a high permeability were used to improve the pulse droop and core losses. The transmission characteristics and pulse time-response were measured to analyze the pulse transformer performance. The data were compared with a simplified lumped constant circuit model. The agreement with the model was very good. The results of high voltage tests using a dummy load are also presented.
A linear Rogowski coil, which was proposed as an electric current probe, was numerically analyzed in this study. In the measurement of the high-frequency pulsed current using the linear Rogowski ...coil, the reflection was observed. We confirmed the relationship between the reflection and the terminal resistance of the linear Rogowski coil by numerical analysis using a circuit simulator.
Summary form only given. A 600 kV, 150 ns rise-time pulse transformer with a 1:15 step-up ratio has been developed for klystron pulse modulators. This pulse transformer was designed to produce pulses ...with a peak current of 1200 A, a peak voltage of 600 kV, a rise-time of 150 ns, a flat-top width of 400 ns, and a repetition rate of 50 pps. To realize a fast rise-time, amorphous alloy toroidal cores with a high magnetic flux swing and a high permeability were used, and one-turn primary winding, a bifiler and tapered secondary winding design were adapted to reduce the leakage inductance. The transmission characteristics and pulse time-response were measured to analyze the pulse transformer performance. The data were compared with a distributed circuit model. The agreement with the model was very good. The results of high voltage tests using a dummy load are also presented.
A Chopper-type Marx modulator is being developed to drive a 10 MW L-band multi-beam klystron for the international linear collider at the High Energy Accelerator Research Organization (KEK). Twenty ...units are connected in series to provide the klystron with a -120 kV, 140 A, 1.65 ms pulse at a repetition rate of 5 pps. This paper describes the present status of the Chopper-type Marx modulator being developed at KEK.
Summary form only given. We developed a self-healing capacitor to realize a compact pulse-forming network for klystron pulse modulators. The structure of the capacitor element consists of ...polyethylene terephthalate and polypropylene films, and the former film is coated with thin Ze-electrodes which form series of capacitors. The capacitor has a capacitance rating of 45 nF and a voltage rating of 55 kV, and the dielectric stress was designed to be about 120 V/micrometer. The design life was 9 G shots. Compared to a conventional nonhealing capacitor, the energy density increased more than three times. The capacitors have been operating in the electron linear accelerator of accelerator test facility at KEK and have achieved about 1 G shots without any serious problem, This paper describes the design and test results of the lifetime performance.
Although thyratrons are widely used as high voltage switch devices for pulsed power supplies, their aged degradation and short lifetime has been headache for large accelerator facilities. Especially ...for X-ray free electron laser (XFEL) facilities, an instability caused by the aged thyratron and a high maintenance cost of the thyratron replacement are the serious problem. In order to overcome this problem, we have developed a solid-state high voltage switch having a long lifetime for thyratron replacement. The high-voltage switch was designed to install to the oil-filled compact modulator for XFEL facility SACLA (Spring-8 Angstrom Compact free electron LAser). It should run at a 60 pps (pulse per second) repetition rate and conducts a large current of 5 kA with a 5 us pulse width from the pulse forming network circuit charged at 50 kV in maximum. We employ a static-induction (SI) thyristor as the high-voltage switch, because it has suitable characteristics for the thyratron replacement. In total, 192 SI-thyristors (24 series, 8 parallel) are used for a 50 kV switch module. Since the modulator is filled with an insulation-oil, water cooling of the device is not suitable. Hence, we attach the SI-thyristors on aluminum heat sinks forcibly cooled by oil circulation. Performance check in high-voltage operation for the switch was carried out by connecting it to the actual klystron and modulator. The switch stably run at a 50 kV charging voltage, a 5 kA pulse current and a 60 pps repetition rate. A temperature rise of the SI-thyristor is about 7 degree, which is lower enough. Validity of employing the module for the high-voltage switching is well confirmed.
A high repetition-rate pulsed power generator, which uses IGBT as the main switch, has been developed. It generates high-voltage output of 28 kV that can charge a capacitive load of 12 nF in 100 ns. ...It can be operated at the repetition rate of 6 kHz. A special technique has been applied to the control circuit so that the main storage capacitor is always charged at a constant voltage, even when the output voltage of the charging unit varies for 20%. As a result the timing of the output voltage pulse is stabilized within a range of several nanoseconds. This level of low jitter is considered to be required by the pulsed power supplies for the short-wavelength excimer lasers.
Repetitive pulsed-power generator "ETIGO-IV" Tokuchi, A.; Ninomiya, N.; Jiang, W. ...
PPPS-2001 Pulsed Power Plasma Science 2001. 28th IEEE International Conference on Plasma Science and 13th IEEE International Pulsed Power Conference. Digest of Papers (Cat. No.01CH37251),
2001, Letnik:
2
Conference Proceeding
A new repetitive pulsed-power generator "ETIGO-IV" has been developed for the applications in materials science, pulsed ion-beam acceleration, and high-power microwave generation. It is capable of ...delivering, to a matched load, an output pulse of 400 kV in peak voltage, 13 kA in peak current, and 120 ns in pulsed length, at the repetition rate of 1 Hz. This paper reports the design details and operation results of "ETIGO-IV", as well as the initial experimental results on electron beam production.
Power semiconductor devices (MOSFET, IGBT, SIThy, and SOS) have been studied for applications in repetitive pulsed power generation. These switching devices are expected to be used in pulsed ...high-voltage modulators for accelerators and power supplies for pulsed atmospheric discharges. MOSFET and static-induction thyristor (SIThy) are investigated for their performance in high-voltage modulation at repetition rate on the order of MHz, which is demanded by applications in high-energy particle accelerators. Although the peak voltage and current are not very high (usually a few kV and a few 10s of A respectively), the repetition rate poses fatal problems to the devices due to the thermal effect. The system cooling and waveform control had been the main efforts in this study. IGBT and semiconductor opening switch (SOS) are studied for applications to atmospheric gas discharge, which has become very attractive recently due to its applications in gas-treatment, laser pumping, and sterilization. The electrical circuit scheme is based on inductive energy storage with opening switch, which gives pulsed output high-voltage up to 100 kV for high-impedance load. The study has concentrated on repetition rate and energy efficiency. These developments are joint studies between universities, national laboratories, and industrial companies.
