# Updates on Impact Ionisation Triggering of Thyristors
## 4 Summary  
Our work focuses on developing a novel methodology to trigger industrial thyristors for high-voltage applications, particularly in particle accelerators. Our methodology relies on boosted gate triggering to significantly improve the switching characteristics (dU/dt and dI/dt) of SiC MOSFET devices, allowing for faster and more efficient operation compared to conventional triggering techniques.  
Presently, this paper introduces the latest improvements to the driving of SiC MOSFETs in view of reaching the sufficient output voltage, current and dU/dt to trigger thyristors in the impact ionization mode. In summary, our efforts have resulted in an approach to amplify the current output of our driver circuit, leading to sub-nanosecond performance. By pushing components off the shelf to their limits, we have achieved a pulse generator with an output current exceeding 220 A and a turn-on slew rate exceeding 1 kV/ns. However, the final output voltage falls short of twice the breakdown voltage for the 2.4 kV rated thyristors. To address this limitation, we will incorporate a D2 PAK thyristor Marx generator to meet the requirements of a future stack utilizing the 2.4 kV rated thyristors.  
Despite the challenges faced, the proposed solution offers significant advantages. The use of compact topologies and commercially available components results in a design that is smaller and reproducible, with potential cost benefits. The design of the gate-boosting driver enhances the MOSFET's output voltage, slew rate, and current, enabling faster commutation times and suitability for higher loads, thus facilitating ultra-fast switching. Furthermore, the developed technology's ability to respond rapidly to beam dump requests presents a potential for replacing traditional systems in particle accelerators, promising and improved performance if implemented. Our approach provides a nanosecond delay from trigger request to the output signal, unlike the opening switch approach, which necessitates a preparation period exceeding 500 nanoseconds--a crucial disadvantage compared to our approach.  
Looking forward, our primary objective remains focused on building a stack of thyristors to reach the voltage and current requirements of our target application in the accelerator complex at CERN. The next immediate step involves boosting the output voltage of the described setup using a Marx stage with thyristors triggered in impact ionization (II) mode. Optimization and reliability testing of this stage are currently in progress.  
Presently, we have developed a technology capable of responding to an accelerator's beam dump requests within nanoseconds, thereby reducing the reaction time of existing technologies by two orders of magnitude. Upon establishing the reliability of the whole chain of this triggering method for accelerator systems, there exists the potential for this technology to replace traditional thyratron-based systems.  
Conceptualization, V.S.; methodology, A.A.d.B.M. and V.S.; validation, A.A.d.B.M., V.S. and M.S.; formal analysis, A.A.d.B.M.; investigation, A.A.d.B.M. and V.S.; resources, A.A.d.B.M. and V.S.; data curation, A.A.d.B.M.; writing--original draft preparation, A.A.d.B.M.; writing--review and editing, V.S. and M.S.; visualization, A.A.d.B.M.; supervision, V.S., T.K. and M.S.; project administration, T.K. and M.S.; funding acquisition, T.K. and M.S. All authors have read and agreed to the published version of the manuscript.  
This work has been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Research (grant no. 13E18 CHA).