J. Varju
Charles University in Prague
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Featured researches published by J. Varju.
Review of Scientific Instruments | 2010
M. Lange; M. Froese; Sebastian Menk; J. Varju; Robin Bastert; Klaus Blaum; J. R. Crespo López-Urrutia; Florian Fellenberger; M. Grieser; R. von Hahn; O. Heber; Kai-Uwe Kühnel; Felix Laux; D. A. Orlov; M. L. Rappaport; R. Repnow; C. D. Schröter; D. Schwalm; Andrey Shornikov; T. Sieber; Y. Toker; J. Ullrich; A. Wolf
We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2 x 10(3) cm(-3), which for a room temperature environment corresponds to a pressure in the 10(-14) mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.
Physical Review A | 2009
J. Glosík; R. Plašil; I. Korolov; T. Kotrík; O. Novotný; P. Hlavenka; Petr Dohnal; J. Varju; Viatcheslav Kokoouline; Chris H. Greene
We study binary and the recently discovered process of ternary He-assisted recombination of
Journal of Physics B | 2008
J. Glosík; I. Korolov; R. Plašil; O Novotny; T. Kotrík; P. Hlavenka; J. Varju; Ivan A. Mikhailov; Viatcheslav Kokoouline; Chris H. Greene
\text{H}_{3}{}^{+}
Plasma Physics and Controlled Fusion | 2016
R. Panek; J. Adamek; M. Aftanas; P. Bilkova; P. Bohm; F. Brochard; P. Cahyna; J. Cavalier; R. Dejarnac; M Dimitrova; O. Grover; J Harrison; P. Hacek; J. Havlicek; A. Havranek; J. Horacek; M. Hron; M. Imrisek; F. Janky; A. Kirk; M. Komm; K. Kovařík; J. Krbec; L Kripner; T. Markovic; K. Mitosinkova; Jan Mlynář; D. Naydenkova; M. Peterka; J. Seidl
ions with electrons in a low-temperature afterglow plasma. The experiments are carried out over a broad range of pressures and temperatures of an afterglow plasma in a helium buffer gas. Binary and He-assisted ternary recombination are observed and the corresponding recombination rate coefficients are extracted for temperatures from 77 to 330 K. We describe the observed ternary recombination as a two-step mechanism: first, a rotationally excited long-lived neutral molecule
Physical Review A | 2010
Henrik Buhr; Mario B. Mendes; Oldrich Novotný; D. Schwalm; Max H. Berg; Dennis Bing; O. Heber; Claude Krantz; D. A. Orlov; M. L. Rappaport; Tobias Sorg; Julia Stützel; J. Varju; A. Wolf
\text{H}_{3}{}^{\ensuremath{\ast}}
Journal of Physics: Conference Series | 2011
R. Plašil; J. Varju; Michal Hejduk; Petr Dohnal; T. Kotrík; J. Glosík
is formed in electron-
Journal of Physics: Conference Series | 2010
J. Varju; Štěpán Roučka; T. Kotrík; R. Plašil; J. Glosík
\text{H}_{3}{}^{+}
Journal of Physics: Conference Series | 2009
R. Plašil; I. Korolov; T. Kotrík; J. Varju; Petr Dohnal; Z. Donkó; Gregor Bánó; J. Glosík
collisions. Second, the
Journal of Physics: Conference Series | 2009
I Korolov; T. Kotrík; R. Plašil; Michal Hejduk; J. Varju; Petr Dohnal; J. Glosík
\text{H}_{3}{}^{\ensuremath{\ast}}
Journal of Physics: Conference Series | 2018
E Hasan; M Dimitrova; J. Havlicek; K. Mitosinkova; J. Stöckel; J. Varju; Tsv K Popov; M. Komm; R. Dejarnac; P. Hacek; R. Panek
molecule collides with a helium atom that leads to the formation of a very long-lived Rydberg state with high orbital momentum. We present calculations of the lifetimes of