T. Kanemaki

High Power, Frequency Tunable, Submillimeter Wave ESR Device Using a Gyrotron as a Radiation Source

ESR device using a submillimeter wave gyrotron as a radiation source and a pulse magnet for high field up to 30 T has been constructed. Our gyrotrons (Gyrotron FU series) were developed as millimeter and submillimeter wave radiation sources and have attractive advantages for ESR spectroscopy, for example, high power and frequency tunability over broad range. The ESR device has been successfully applied to three cases of ESR measurements. In the first case, the temperature dependence of ESR was measured for a typical antiferromagnetic material MnO at the frequency of 301 GHz. In the second case, the dependence of the fine structure constant of the ruby on the magnetic field intensity was measured in the millimeter to submillimeter wave region. In these two cases, the gyrotron was operated by complete cw mode. In the final case, a pulse technique was applied to the ESR, the gyrotron was operated in pulse mode and the pulsed magnetic field was generated in the synchronized phase with the gyrotron operation.

ESR spectrometer with a wide frequency range using a gyrotron as a radiation power source

The development of a high frequency electron spin resonance (ESR) spectrometer with a wide frequency range using a gyrotron as the radiation power source is described.GYROTRON FU-E, optimized for use in an ESR spectrometer in the millimeter wave range, was developed in Fukui University. In order to test the normal operation of the spectrometer, the ESR of two standard samples, single crystal and polycrystalline DPPH, has been measured, in the pulsed mode over the frequency range from 65 GHz to 135 GHz.

Development of a second cyclotron harmonic gyrotron operating at 0.8 mm wavelength

This letter describes the development of a submillimeter wave gyrotron operating at the second harmonic of the cyclotron frequency. The observed frequency is 383 GHz, which corresponds to the wavelength of 0.79 mm, and the output power is about 1 kW. We believe that the frequency is a world record for a stable, long pulse gyrotron operation at the second cyclotron harmonic, without a competition with the operation at the fundamental. Comparisons with the simulation results are represented.

Development of a high‐frequency, second‐harmonic gyrotron tunable up to 636 GHz

In this Letter, a high‐frequency, second‐harmonic gyrotron using a 12 T superconducting magnet is described. It has achieved a maximum frequency of 636 GHz (corresponding to a wavelength of 472 μm). Operating at both the fundamental and the second harmonic of the electron cyclotron frequency enables the gyrotron to act as a high power (several 100 W), step tunable, millimeter to submillimeter wave source in the wide frequency range from 150 to 630 GHz.

Development of Submillimeter Wave Catheter Transmitting a Gyrotron Output for Irradiation on Living Bodies

The development of a millimeter and submillimeter wave catheter for irradiation on living bodies using a gyrotron as the radiation power source is described. The GYROTRON FU-IV, optimized for such applications was used in the development. It was operated in both CW and pulsed regime at TE03 and TE32 modes with frequencies 302 GHz and 238 GHz respectively. Irradiation tests were made on thermal papers, beefs and liver of living rats.

Development of high frequency, cyclotron harmonic gyrotron oscillator

Abstract The oscillation results of a high frequency gyrotron which operates at the fundamental cyctron frequency and its higher harmonics ( s =1, 2, 3) are described. The fairly high frequency of 220 GHz (corresponding wave length 1.35 mm) has been achieved at the fundamental and second harmonic of the cyclotron frequency. The scaling law of output power to harmonic number s is also described.

Submillimeter Wave Irradiation of Living Bodies using a Gyrotron and a Catheter

The development of a submillimeter wave catheter for irradiating on living bodies using a gyrotron as the radiation power source is described. The gyrotron FU-IV is optimized for development. The gyrotron is operated in the CW mode at a frequency of 302 GHz under a magnetic field of approximately 11 T. Irradiation tests using various antennas were performed on cow livers, living rats and malignant tumors implanted in living mice. Irradiation results were considered based on the microwave theory and ray optics.

High‐frequency, step tunable, cyclotron harmonic gyrotron

The performance of a high‐frequency gyrotron that operates at the fundamental of the electron cyclotron frequency and its higher harmonics is described. The high frequency of 220 GHz (corresponding wavelength 1.35 mm) has been achieved at both the fundamental and second harmonic. The dependence of output power on magnetic field and beam parameters and the scaling law of output power with harmonic numbers are described. The results are compared with a computer simulation.

Characteristics of a Teflon Rod Antenna for Millimeter- and Submillimeter-Wave Irradiation on Living Bodies

The development of a millimeter- and submillimeter-wave catheter for irradiation on living bodies using a Teflon rod dielectric antenna is described. The power sources of electromagnetic wave are an Impatt oscillator (90 GHz, 0.3 W) and a gyrotron (302 GHz, 30 W). Irradiation tests using various Teflon rod dielectric antennas were performed on cow livers, living rats and a cancerous tumor implanted in living mice. Irradiation results were considered by microwave theory and ray optics.

Ruby ESR Over a Wide Frequency Range in the Millimeter Wave Region

The ESR of Cr3+ in dark ruby is measured using a high frequency ESR spectrometer with a wide frequency range which uses a gyrotron as the radiation source. For this purpose, GYROTRON FU- IV A developed at Fukui University was optimized for use in an ESR apparatus operating in the millimeter-wave range.The observed fine structure constant D for ruby is found to be D ∼−5.728 GHz and the g-values g∥ ∼1.981, g ⊥ ∼1.982. Both the values of |D| and g are smaller than those obtained at lower frequencies by other work. Higher order terms of the spin hamiltonian are discussed in order to understand the ruby ESR results in this higher frequency range.