Development and applications of high-quality gyrotrons -Ultra high power gyrotrons and ultra high frequency gyrotrons-

high frequency,medium power gyrotrons (gyrotrons FU series) achieved the highest frequency of 889ghz for singlemode operation at the second harmonic (N=2) and the frequency step-tunability from 38 to 889 GHzusing the fundamental, secondthird harmonic operation. Output powers of several hundred watts at the fundamentals and severalten watts at second harmonics have been achieved.As a result of the feedback control of the anodepotential we succeeded to reduce the fluctuation level of the cw output power （f= 301ghz）P= 20w) from 3.7% to 1.5%. The fluctuation level could be decreased down to 0.6% by reducingfluctuation level of the cathode potential below 3v . As a result of the control of the anodepotential we succeeded to modulate the gyrotron output with a modulation frequency up to 20khz . theconversion system consists of a quasi-optical antennasequence of two ellipsoidal focusing mirrors and a spatial filter.这是打算要配置四个TE - D21n - D2 mode outputs of the Gyrotron FU IVA (TE - D212 - D2, 170 GHz; TE - D213 - D2, 271 GHz；TE - i D214 - ii D2, 372 GHz；TE - D215 - D2，472 GHz) into gaussian-like beams with waist size of w - 2x" D2=w - 2y" D2=16.3 mm as well asthree TE - D20n - D2 modes (TE - D202 - D2, 223ghz; TE - D203 - D2, 323ghz；TE - D204 - D2，423ghz) into bigaussian-like beams with waist sizes of wi D2x" D2= 23.5 mm and wi D2yo" D2=16.4mm. Compared with the earlier system capable of converting只有一个操作模式the novel one is更多versatile and is compatible with frequency tunable gyrotrons such as the Gyrotron FU IVA. Inspite of the truncation of the sidelobes of the beam by the spatial filter most of the image sourcepower is transferred to the final waist. As a result，intense high quality beams in the submillimeter wavelength range can be produced。

High frequency, medium power gyrotrons (Gyrotrons FU series) achieved the highest frequency of 889 GHz for single mode operation at the second harmonic (N=2) and the frequency step-tunability from 38 to 889 GHz using the fundamental, second, and third harmonic operation. Output powers of several hundred watts at the fundamentals and several ten watts at second harmonics have been achieved.As a result of the feedback control of the anode potential we succeeded to reduce the fluctuation level of the cw output power (f=301 GHz, P=20 W) from 3.7% to 1.5%. The fluctuation level could be decreased down to 0.6% by reducing fluctuation level of the cathode potential below 3 V. As a result of the control of the anode potential we succeeded to modulate the gyrotron output with a modulation frequency up to 20 kHz.The conversion system consists of a quasi-optical antenna, sequence of two ellipsoidal focusing mirrors and a spatial filter. It is intended to convert four TEィイD21nィエD2 mode outputs of the Gyrotron FU IVA (TEィイD212ィエD2, 170 GHz; TEィイD213ィエD2, 271 GHz; TEィイD214ィエD2, 372 GHz; TEィイD215ィエD2, 472 GHz) into gaussian-like beams with waist size of wィイD2x"ィエD2=wィイD2y"ィエD2=16.3 mm as well as three TEィイD20nィエD2 modes (TEィイD202ィエD2, 223 GHz; TEィイD203ィエD2, 323 GHz; TEィイD204ィエD2, 423 GHz) into bigaussian-like beams with waist sizes of wィイD2x"ィエD2 =23.5 mm and wィイD2yo"ィエD2=16.4 mm. Compared with the earlier system capable of converting only one operating mode the novel one is more versatile and is compatible with frequency tunable gyrotrons such as the Gyrotron FU IVA. In spite of the truncation of the sidelobes of the beam by the spatial filter most of the image source power is transferred to the final waist. As a result, intense high-quality beams in the submillimeter wavelength range can be produced.