Design of a CW 1 THz Gyrotron (Gyrotron Fu Cw III) Using a 20 T Superconducting Magnet

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A CW gyrotron for the sensitivity enhancement of NMR spectroscopy through dynamic nuclear polarization has been designed. The gyrotron operates at the second harmonic and frequency of 394.6 GHz with the main operating mode TE 0,6 . Operating conditions of other neighboring cavity modes such as TE 2,6 at frequency of 392.6 GHz and TE 2,3 at frequency of 200.7 GHz were also considered. The experimental conditions of the gyrotron at low and high voltages are simulated. The output power of 56 watts corresponds to the efficiency of 2 percent at low voltage operation and frequency of 394.6 GHz is expected.

“…The physical model of mode competition used here (based on the ref. [18]) has been described in [19]. Operation conditions both at high and low-voltages are described.…”

Section: Optimization Of the Gyrotron Parametersmentioning

confidence: 99%

Detailed Consideration of Experimental Results of Gyrotron FU CW II Developed as a Radiation Source for DNP-NMR Spectroscopy

Agusu

Idehara

Ogawa

et al. 2007

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“…On the basis of this success, we have designed the next gyrotron, Gyrotron FU CW III with a 20 T superconducting magnet, which operates in THz frequency range at the second harmonics. [22] The 20 T magnet has already arrived at FIR FU and the construction of the demountable gyrotron tube has been completed. We have already operated it successfully in complete CW mode.…”

Section: Discussionmentioning

confidence: 99%

“…The development of the first gyrotron, Gyrotron FU CW I was completed and CW output of 1.75 kW was obtained at the frequency of 300 GHz. The cavity mode is TE 22,8 at the fundamental operation. [20,21] The second gyrotron, Gyrotron FU CW II [14][15][16] was constructed and the operation test has been carried out.…”

Section: Introductionmentioning

confidence: 99%

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Long Pulse Operation of the THz Gyrotron with a Pulse Magnet

Idehara¹,

Saito²,

Mori³

et al. 2007

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Long pulse operation up to 1 msec of a high frequency gyrotron with a pulse magnet has been successfully carried out in a frequency range including 1 THz. In the experiments, the timing of an electron beam pulse injection is adjusted at the top of the magnetic field pulse, where the variation of field intensity is negligible. The operation cavity modes seem to be TE 1, 12 and TE 4,12 at the second harmonics. The corresponding frequencies are 903 GHz and 1,013 GHz, respectively. Additionally several features of radiation measurement results of the gyrotron are described and brief considerations are presented.

“…It will be used as a power source of DNP-NMR for protein analysis. FU CW III aims at fully continuous oscillation at a frequency over 1 THz with tens of Watts [15]. High power terahertz technologies will be developed with CW III.…”

mentioning

confidence: 99%

Performance Test of CW 300 GHz Gyrotron FU CW I

Saito

Nakano

Hoshizuki

et al. 2007

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A 300 GHz CW gyrotron FU CW I has been developed and installed in the Research Center for Development of Far-Infrared Region, University of Fukui as a power source of a high frequency material processing system. Its performance was tested and the maximum power of 1.75 kW / CW has been attained at the beam voltage of 15 kVand the beam current of 1A. The maximum window power efficiency of 15.5% has been obtained at the cathode voltage slightly lower than 15 kV. This gyrotron is designed to deliver a Gaussian beam after mode conversion from the oscillation mode TE 22,8 in the cavity with a complex of an internal radiator and beam shaping mirrors. The detailed measurement with an infrared camera has confirmed that a Gaussian beam is radiated when the magnetic field strength B c at the cavity is adjusted at a proper value. However, within a range of B c , the output power is emerged into multiple directions, which suggests simultaneous oscillation of competing cavity modes.