A5083584913- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Microwave Engineering and Waveguides
- Magnetic confinement fusion research
- Terahertz technology and applications
- Pulsed Power Technology Applications
- Acoustic Wave Resonator Technologies
- Plasma Diagnostics and Applications
- Particle Accelerators and Free-Electron Lasers
- Ionosphere and magnetosphere dynamics
- Advanced Condensed Matter Physics
- Muon and positron interactions and applications
- Microwave-Assisted Synthesis and Applications
- Dust and Plasma Wave Phenomena
- Superconducting and THz Device Technology
- Advanced NMR Techniques and Applications
- Magnetic and Electromagnetic Effects
- Physics of Superconductivity and Magnetism
- Solid-state spectroscopy and crystallography
- Atomic and Subatomic Physics Research
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Insects and Parasite Interactions
- Atomic and Molecular Physics
- Photonic and Optical Devices
University of Fukui
2012-2021
Fukui University of Technology
1997-2020
National Academy of Sciences of Ukraine
2017
Institute of Applied Physics
2017
Institute of Electronics
2017
Bulgarian Academy of Sciences
2017
Fukuda Denshi (Japan)
2017
Osaka University
2017
O.Ya. Usikov Institute for Radiophysics and Electronics
2017
National Tsing Hua University
2010
The magnetic susceptibility, high field magnetization, and specific heat measurements of Cu3(CO3)2(OH)2, which is a model substance for the frustrating diamond spin chain model, have been performed using single crystals. Two broad peaks are observed at around 20 5 K in both susceptibility results. magnetization curve has clear plateau one third saturation magnetization. experimental results examined terms theoretical expectations based on exact diagonalization density matrix renormalization...
The gyrotrons are powerful sources of coherent radiation that can operate in both pulsed and CW (continuous wave) regimes. Their recent advancement toward higher frequencies reached the terahertz (THz) region opened road to many new applications broad fields high-power science technologies. Among them advanced spectroscopic techniques, most notably NMR-DNP (nuclear magnetic resonance with signal enhancement through dynamic nuclear polarization, ESR (electron spin resonance) spectroscopy,...
We report a frequency tunable scheme for the gyrotron at millimeter/submillimeter regime. Unlike step-tunable type where oscillation frequencies change discretely, this continuously adjusts as magnetic field varies. It is hybrid system, taking advantages of backward-wave interaction and converter-free output structure. The characteristics will be shown. A proof principle experiment was conducted with scaled cavity. result shows smoothly transitions over wide range 6 GHz from 134 to 140 GHz....
The maximal frequency of radiation higher than 1 THz has been recently obtained in pulse gyrotrons both at IAP (Nizhny Novgorod, Russia) and FIR (Fukui, Japan). CW generation a 2.2-kW power level is radiated from 300-GHz gyrotron used for technological applications. New demonstrate single-mode operation the second cyclotron harmonic with 395 GHz regime 100 W third frequencies 371-414 10-mus pulses 10-20 kW. Methods selective excitation harmonics, multiplication, smooth tuning terahertz are...
In this paper, we present some of the most significant recent results that characterize state art in development sub-THz and THz gyrotrons at IAP-RAS FIR-UF after 15 years collaboration as well their applications various novel prospective research fields advanced technologies.
Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B0<9T) and temperatures (T>90K) with potential applications in chemistry material sciences. However, considering the ever-increasing size complexity systems to be studied, it crucial establish DNP under higher field conditions, where spectral resolution basic sensitivity tend improve. In this perspective, we overview our recent efforts on hardware developments, specifically...
Polymerization of monomeric actin into filaments has pivotal roles in cell motility, growth, differentiation, and gene expression. Therefore, techniques manipulating polymerization, including actin-binding chemicals, have been developed for understanding regulating multiple biological functions. Here, we demonstrate that irradiation with terahertz (THz) waves is a novel method modulating polymerization. When polymerization reaction performed under 0.46 THz generated by Gyrotron, was observed...
High frequency, medium power gyrotrons (Gyrotron FU series) have been developed at Fukui University as radiation sources covering a broad band from millimeter to submillimeter wave region. They already applied high frequency electron spin resonance and scattering in plasma. Many parameters of the gyrotron series could be useful for applications several new areas. The development some Gyrotron are summarized this paper.
Record-breaking high power coherent radiation at a subterahertz frequency region from gyrotron utilizing second harmonic resonance modes was attained with simple cavity. In order to aim and simultaneously, the oscillation mode selected carefully enough realize stable free competition. The cavity radius determined viewpoints of frequency, coupling coefficient between electron beam, rf-electric field. length also optimized for highest perpendicular efficiency. addition, new gun which is...
Instrumentation for high-field dynamic nuclear polarization (DNP) at 14.1 T was developed to enhance the NMR of solids. The gyrotron generated 394.5 GHz submillimeter (sub-mm) wave with a power 40 W in second harmonic TE0,6 mode. sub-mm 0.5–3 transmitted sample low-temperature DNP-NMR probe smooth-wall circular waveguide system. 1H enhancement factor up about 10 observed 13C-labeled compound nitroxyl biradical TOTAPOL. DNP confirmed by static magnetic field dependence signal amplitude 90 K....
New power records of second harmonic gyrotron oscillation have been demonstrated in the sub-THz band. The first step demountable type had succeeded with more than 50 kW at 350 GHz and nearly 40 390 [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009)]. Then, sealed-off was manufactured. A cavity mode carefully selected to avoid competition a neighboring fundamental mode. Matching electron gun also circumspectly considered. has attained higher radiation gyrotron. maximum single 62 388 GHz....
We present the first experimental results of study on a novel second harmonic THz-band double-beam gyrotron. The tube has demonstrated stable single-mode operation with output parameters that are appropriate for next-generation 1.2 GHz dynamic nuclear polarization-nuclear magnetic resonance spectroscopy. Besides design mode (TE8,5), series other fundamental and modes have been excited. This makes new gyrotron versatile radiation source, which can be used also in applications high-power...
An account of the operation a step-tunable, low-power, continuous-wave gyrotron, GYROTRON V, at fundamental and second harmonic electron cyclotron frequency is presented. The design this gyrotron was especially optimized for harmonic. operating can be tuned from 150 to 300 GHz extended by second-harmonic above 600 GHz. Under normal conditions where accelerating voltage 10 kV beam current 50 mA, power levels in excess 20 W are obtained hundreds milliwatts paper includes observations single...
A gyrotron with an axis-encircling electron beam is capable of high-frequency operation, because the high-beam efficiency kept even at high harmonics cyclotron frequency. We have designed and constructed such a permanent magnet. The has already operated successfully third, fourth, fifth harmonics. frequencies are 89.3, 112.7, 138 GHz, respectively, corresponding cavity modes TE/sub 311/, 411/, 511/. magnet system quite novel consists many elements made NbFeB additional coils for controlling...
Dynamic mode interaction between fundamental and second-harmonic modes has been observed in high-power sub-terahertz gyrotrons [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009); T. Saito al. Plasmas 19, 063106 (2012)]. Interaction takes place a parasitic or first-harmonic (FH) an operating (SH) mode, as well among SH modes. In particular, nonlinear excitation of the FH hard self-excitation regime with assistance soft was clearly observed. Moreover, both cases stable two-mode oscillation...