@article{3034939, title = "Generation of 1.5 MW-140 GHz Pulses with the Modular Pre-Prototype Gyrotron for W7-X", author = "Ioannidis, Z.C. and Avramidis, K.A. and Rzesnicki, T. and Chelis, I. and Gantenbein, G. and Illy, S. and Jin, J. and Pagonakis, I.G. and Thumm, M. and Jelonnek, J.", journal = "IEEE Electron Device Letters", year = "2021", volume = "42", number = "6", pages = "939-942", publisher = "Institute of Electrical and Electronics Engineers, Inc. (IEEE)", issn = "0741-3106, 1558-0563", doi = "10.1109/LED.2021.3073221", keywords = "Cyclotrons; Electron cyclotron resonance; Gyrotrons; Stellarators; Tokamak devices, Continuous wave gyrotrons; Electron beam optics; Electron cyclotron resonance heating; Experimental campaign; Experimental verification; Short pulse; WENDELSTEIN 7-X, Ultrafast lasers", abstract = "In anticipation of an Electron Cyclotron Resonance Heating system upgrade for the stellarator Wendelstein 7-X, a 1.5 MW - 140 GHz continuous-wave gyrotron is under development. In order to provide a first experimental verification of the scientific RF and electron beam optics design of the gyrotron with ms pulses, the Karlsruhe Intitule of Technology has developed a short-pulse pre-prototype gyrotron. In this work, we present details regarding the construction of the pre-prototype as well as measurements from the first experimental campaign delivering up to 1.6 MW in short pulses. © 1980-2012 IEEE." }