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For DNP-NMR spectroscopy, we need high power sub-THz radiation sources with the output power of several tens watts. We have developed Gyrotrons FU CW VII operating in 200 GHz band and 400 GHz band as radiation source for 600 MHz and 300 MHz DNP-NMR spectroscopy. We have installed it at University of Warwick. UK and begun the DNP-NMR measurement.
A Gytrotron FU CW III using a 20 T superconducting magnet has been developed as a radiation source in the THz region. At the first experiment, several radiation by fundamental operation were observed and measured frequencies.
Two sealed-off gyrotron tubes for high power THz spectroscopy are designed and constructed. One of them will be used for ESR echo experiment in sub-THz region, and another for 600 MHz DNP-NMR experiment etc. Both gyrotrons are named Gyrotron FU CW IIA and Gyrotron FU CW VIIA, because their cavities have same shapes as Gyrotrons FU CW II and FU CW VII. Both tubes are installed in 8T superconducting...
A novel high power sub-terahertz gyrotron operating at second harmonic resonance was designed. This gyrotron is intended for use as a probe beam source for collective Thomson scattering diagnostics in nuclear fusion plasma research. The resonant cavity mode, cavity radius, and its length were optimized from various aspects such as resonant frequency, coupling between the electron beam and the RF-electric...
Gyrotron FU CW V operating at the fundamental cyclotron resonance is used for measurement of hyperfine structure on positronium. The gyrotron delivers high power radiation with the frequency of 203.2 GHz and output power of 0.7 kW under CW operation mode. This radiation can be used for direct measurement of energy level transition of positronium, because expected energy level difference is near 203...
We have developed the Gyrotron FU CW VII for 300 MHz and 600 MHz DNP-NMR spectroscopy. For high frequency DNP-NMR experiment, high power sub-THz radiation sources are required. Gyrotron is able to emit enough power and appropriate frequency in sub-THz region for DNP. This Gyrotron emits electromagnetic waves with high power and appropriate frequency for each DNP-NMR spectroscopy (used cavity modes...
A high power sub terahertz pulse gyrotron is under development in FIR-FU for application to collective Thomson scattering from a high density plasma in the large helical device. As a step to the final goal, a second harmonic gyrotron using a newly designed electron gun was fabricated aiming at 50 kW at around 400 GHz. Oscillation modes were carefully selected from the view point of mode separation...
We present a frequency tunable scheme for the gyrotron at millimeter/submillimeter regime. Unlike step-tunable type where oscillation jumps discretely in different transverse modes, this scheme allows a smooth tuning within a single transverse mode using its backward-wave component. The characteristics of backward-wave interaction will be shown. A proof of principle experiment was conducted with a...
On the basis of successful development of Gyrotron FU CW II, a similar gyrotron FU CW IIA is being developed for both 600 MHz and 300 MHz DNP-NMR experiments at the University of Warwick in UK. The frequencies of the gyrotron are 394.6 GHz at the second harmonic and 200 GHz at fundamental that correspond to frequencies 600 MHz and 200 GHz DNP-NMR spectroscopy. The output powers are around 30 W and...
Accurate measurement of difference between energy levels of positronium is a current important subject in the experimental physics of elementary particles. The frequency corresponding to the energy difference is about 203.39 GHz. At least, 100 watt CW power is requested for the direct measurement. We are now designing such a gyrotron FU CW V consisting of an 8 T superconducting magnet and a demountable...
Summary form only given. Recently, medium power, sub-THz gyrotrons were developed for application to DNP-NMR experiment for enhancing the sensitivity of NMR. In FIR FU, 394.6 GHz CW gyrotron FU CW II which is the second gyrotron of Gyrotron FU CW Series has been developed for DNP/NMR at 600 MHz under a collaboration with Institute of Protein Research, Osaka University. The output power and the frequency...
Recently, a gyrotron in FIR FU with a 21 T pulse magnet achieved the breakthrough of 1 THz. In the gyrotron, a demountable gyrotron tube is installed on the center axis of 21 T pulse magnet. In the operation test, a high voltage pulse is applied to electron gun installed in the region of the additional coils for controlling the injection point of electron beam in the cavity region. When B in the cavity...
Summary form only given. Dynamic nuclear polarization (DNP) method can enhance the sensitivity of NMR for extending its application to wide fields including analysis of protein molecule and study on material surface. For this objective, it is needed to develop high power sub-THz radiation sources which operate in long time CW mode. We have already developed a 395 GHz CW gyrotron for 600 MHz proton...
The new gyrotron series in FIR FU, so-called gyrotron FU CW series is being developed for application to high power THz technologies. Gyrotron FU CW II with an 8 T liquid He free superconducting magnet, the second gyrotron of the series, has been constructed and the operation test was successfully carried out. It will be used for enhancing the sensitivity of 600 MHz proton-NMR by use of dynamic nuclear...
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