Browsing by Author "Kandratsyeu, Aleh"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Design strategies for a SiC Marx generator for a kicker magnetPublication . Redondo, Luis; Kandratsyeu, Aleh; Barnes, Mike; Fowler, TonyKicker magnets are specialised elements of the beam transfer system of particle accelerators, used to inject and extract beam from an accelerator. The deflection field produced by kicker magnets must rise/fall within the time period between the beam bunch trains; hence they typically produce rectangular field pulses with fast rise- and/or fall-times. In addition, the field must not significantly deviate from the flat top of the pulse or from zero between pulses. Typical field rise/fall-times range from tens to hundreds of nanoseconds and pulse widths range from tens of nanoseconds to tens of microseconds. Most existing kicker systems at CERN rely on established technologies, which include thyratron switches and pulse-forming networks/lines (PFN/PFL). For thyratrons, long-term availability is a concern: hence alternate fast-switch technologies, based on high power semiconductor devices, such as the Marx generator are being actively pursued. A Marx generator topology would also potentially resolve problems associated with pulse forming: PFNs are complex devices built of many discrete components, difficult to adjust for optimisation of pulse-shapes, and PFLs rely on difficult-to-source cable for the highest voltage (≈80kV) kicker systems. This paper presents design strategies and preliminary test results for a Marx generator with specifications of 40kV, 3.2kA, 3microseconds pulse width, 30ns rise and fall-times, and 1Hz repetition rate, for possible replacement of an existing kicker thyratron/PFL system. The proposed topology will use 50 stages, each 800V stage comprising 24 SiC MOSFETs in parallel, each MOSFET conducting almost 140A pulses. First tests using single and parallel SiC MOSFETs will be described and results discussed in light of the proposed topology. Also the structure of the complete system will be discussed, as the parasitic inductances are a key issue in this application.
- Four channel 6.5 kV, 65 A, 100 ns-100 mu s generator with advanced control of pulse and burst protocols for biomedical and biotechnological applicationsPublication . Kandratsyeu, Aleh; Sabaleuski, Uladzimir; Redondo, Luis; Pakhomov, AndreiFeatured Application Pulsed generator for biomedical and biotechnology applications. Pulsed electric fields in the sub-microsecond range are being increasingly used in biomedical and biotechnology applications, where the demand for high-voltage and high-frequency pulse generators with enhanced performance and pulse flexibility is pushing the limits of pulse power solid state technology. In the scope of this article, a new pulsed generator, which includes four independent MOSFET based Marx modulators, operating individually or combined, controlled from a computer user interface, is described. The generator is capable of applying different pulse shapes, from unipolar to bipolar pulses into biological loads, in symmetric and asymmetric modes, with voltages up to 6.5 kV and currents up to 65 A, in pulse widths from 100 ns to 100 mu s, including short-circuit protection, current and voltage monitoring. This new scientific tool can open new research possibility due to the flexibility it provides in pulse generation, particularly in adjusting pulse width, polarity, and amplitude from pulse-to-pulse. It also permits operating in burst mode up to 5 MHz in four independent channels, for example in the application of synchronized asymmetric bipolar pulses, which is shown together with other characteristics of the generator.