caa a22 4500 445305517 CHVBK 20180317142611.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s10762-010-9708-y doi (NATIONALLICENCE)springer-10.1007/s10762-010-9708-y Development of THz-range Gyrotrons for Detection of Concealed Radioactive Materials [Elektronische Daten] [Gregory Nusinovich, Ruifeng Pu, Thomas Antonsen Jr., Oleksandr Sinitsyn, John Rodgers, Ali Mohamed, Joseph Silverman, Mohamad Al-Sheikhly, Yakov Dimant, Gennady Milikh, Michael Glyavin, Alexei Luchinin, Eugene Kopelovich, Victor Granatstein] The Center for Applied Electromagnetics (AppEl) at the University of Maryland had started development of a sub-THz gyrotron for detecting concealed radioactive materials. The concept is based on the use of a high-power gyrotron whose power being focused in a small spot with dimensions on the order of a wavelength exceeds the threshold level required for initiating a freely localized microwave breakdown in air. However, in the absence of radioactive materials, the ambient electron density is so small that there is a very small probability to find a free electron in this small volume to trigger the avalanche breakdown process. Therefore the fact that the breakdown was observed would indicate that there is a hidden radioactive material in the vicinity of a focused wave beam. We present the design data for a 200-300kW, 670GHz gyrotron operating with a pulsed solenoid and describe a single-shot pulsed solenoid producing 27-28T magnetic fields. Also numerous issues in this specific application are discussed, viz. threshold conditions for initiating the breakdown, production of gamma rays by concealed radioactive materials and their role in producing low energy electrons outside a container, wave beam focusing in a small spot by a limited-size antenna, random walk of energetic electrons which may result in appearance of free electrons in a given volume during the RF pulse and comparison of diffusion time with the time required for competing processes, such as ionization and three-body attachment. Springer Science+Business Media, LLC, 2010 Gyrotron nationallicence Pulse solenoid nationallicence Radioactive materials nationallicence RF breakdown nationallicence THz radiation nationallicence Nusinovich Gregory Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut Pu Ruifeng Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut Antonsen Jr. Thomas Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut Sinitsyn Oleksandr Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut Rodgers John Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut Mohamed Ali Graduate Program in Nuclear Engineering, A. James Clark School of Engineering, University of Maryland, 20742-3511, College Park, MD, USA aut Silverman Joseph Graduate Program in Nuclear Engineering, A. James Clark School of Engineering, University of Maryland, 20742-3511, College Park, MD, USA aut Al-Sheikhly Mohamad Graduate Program in Nuclear Engineering, A. James Clark School of Engineering, University of Maryland, 20742-3511, College Park, MD, USA aut Dimant Yakov Center for Space Physics, Boston University, 02215, Boston, MA, USA aut Milikh Gennady Department of Astronomy, University of Maryland, 20742, College Park, MD, USA aut Glyavin Michael Consortium GYCOM, 603600, Nizhny Novgorod, Russia aut Luchinin Alexei Consortium GYCOM, 603600, Nizhny Novgorod, Russia aut Kopelovich Eugene Consortium GYCOM, 603600, Nizhny Novgorod, Russia aut Granatstein Victor Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut Journal of Infrared, Millimeter, and Terahertz Waves Springer US; http://www.springer-ny.com 32/3(2011-03-01), 380-402 1866-6892 32:3<380 2011 32 10762 https://doi.org/10.1007/s10762-010-9708-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10762-010-9708-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nusinovich Gregory Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Pu Ruifeng Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Antonsen Jr Thomas Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Sinitsyn Oleksandr Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Rodgers John Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Mohamed Ali Graduate Program in Nuclear Engineering, A. James Clark School of Engineering, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Silverman Joseph Graduate Program in Nuclear Engineering, A. James Clark School of Engineering, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Al-Sheikhly Mohamad Graduate Program in Nuclear Engineering, A. James Clark School of Engineering, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 700 1- Dimant Yakov Center for Space Physics, Boston University, 02215, Boston, MA, USA aut NATIONALLICENCE 700 1- Milikh Gennady Department of Astronomy, University of Maryland, 20742, College Park, MD, USA aut NATIONALLICENCE 700 1- Glyavin Michael Consortium GYCOM, 603600, Nizhny Novgorod, Russia aut NATIONALLICENCE 700 1- Luchinin Alexei Consortium GYCOM, 603600, Nizhny Novgorod, Russia aut NATIONALLICENCE 700 1- Kopelovich Eugene Consortium GYCOM, 603600, Nizhny Novgorod, Russia aut NATIONALLICENCE 700 1- Granatstein Victor Institute for Research in Electronics and Applied Physics, University of Maryland, 20742-3511, College Park, MD, USA aut NATIONALLICENCE 773 0- Journal of Infrared, Millimeter, and Terahertz Waves Springer US; http://www.springer-ny.com 32/3(2011-03-01), 380-402 1866-6892 32:3<380 2011 32 10762 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer