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NEW METHOD OF EFFICIENCY ENHANCEMENT IN FREE-ELECTRON MASERS
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作者 张世昌 刘盛纲 《Science China Mathematics》 SCIE 1989年第6期726-735,共10页
A new method is proposed to enhance the efficiency of free-electron maser (EM). Aradial electrostatic field is introduced to assist the axial magnetic field to focus a large-orbitclectron beam. A new kind of azimuthal... A new method is proposed to enhance the efficiency of free-electron maser (EM). Aradial electrostatic field is introduced to assist the axial magnetic field to focus a large-orbitclectron beam. A new kind of azimuthal bunching mechanism. caused by the angular-momentum effect, is demonstrated. Nonlinear simulation of the interaction between a rela-tivistic electron beam and TE_(5,1,1) mode or TE_(10,1,1) mode shows that, as long as the initialparameters are properly chosen, the method is valid. 展开更多
关键词 free-electron maser STANDING wave coaxial waveguide relativistic EFFECT ANGULAR-MOMENTUM effect.
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A UNIFIED DESCRIPTION OF FREE-ELECTRON MASERS——GYROKINETICS
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作者 张世昌 《Science China Mathematics》 SCIE 1991年第4期489-499,共11页
The instabilities of gyrotron, gyro-peniotron and cyclotron auto-resonance masers(CARM) and their relationship are analysed in detail. By introducing gyrokinetic variablesin the Vlasov equation, a unified description,... The instabilities of gyrotron, gyro-peniotron and cyclotron auto-resonance masers(CARM) and their relationship are analysed in detail. By introducing gyrokinetic variablesin the Vlasov equation, a unified description, i.e. the gyrokinetics, of these free-electronmasersisgiven. 展开更多
关键词 free ELECTRON maser CYCLOTRON auto-resonance gyrokinetics.
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Capturing the non-equilibrium state in light–matter–free-electron interactions through ultrafast transmission electron microscopy
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作者 汪文韬 孙帅帅 +5 位作者 李俊 郑丁国 黄思远 田焕芳 杨槐馨 李建奇 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期88-101,共14页
Ultrafast transmission electron microscope(UTEM) with the multimodality of time-resolved diffraction, imaging,and spectroscopy provides a unique platform to reveal the fundamental features associated with the interact... Ultrafast transmission electron microscope(UTEM) with the multimodality of time-resolved diffraction, imaging,and spectroscopy provides a unique platform to reveal the fundamental features associated with the interaction between free electrons and matter. In this review, we summarize the principles, instrumentation, and recent developments of the UTEM and its applications in capturing dynamic processes and non-equilibrium transient states. The combination of the transmission electron microscope with a femtosecond laser via the pump–probe method guarantees the high spatiotemporal resolution, allowing the investigation of the transient process in real, reciprocal and energy spaces. Ultrafast structural dynamics can be studied by diffraction and imaging methods, revealing the coherent acoustic phonon generation and photoinduced phase transition process. In the energy dimension, time-resolved electron energy-loss spectroscopy enables the examination of the intrinsic electronic dynamics of materials, while the photon-induced near-field electron microscopy extends the application of the UTEM to the imaging of optical near fields with high real-space resolution. It is noted that light–free-electron interactions have the ability to shape electron wave packets in both longitudinal and transverse directions, showing the potential application in the generation of attosecond electron pulses and vortex electron beams. 展开更多
关键词 ultrafast transmission electron microscopy non-equilibrium structural dynamics photo-induced phase transition free-electron–photon interactions
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OH megamaser的光度和它们的宿主星系的红外光度之间的相关关系 被引量:2
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作者 俞志尧 《天文学报》 CSCD 北大核心 2002年第4期347-352,共6页
利用66个OH megamaser的光度和它们的宿主星系的红外光度之间的相关关系,得到log L(OH)=1.71log L(IR)-17.67,即L(OH)α[L(IR)]1。71.这个结果介于Baan所得到的L(OH)α[L(IR)]2和Kandalian所得到的L(OH)α[L(IR)]1.38的结果之间.由于统... 利用66个OH megamaser的光度和它们的宿主星系的红外光度之间的相关关系,得到log L(OH)=1.71log L(IR)-17.67,即L(OH)α[L(IR)]1。71.这个结果介于Baan所得到的L(OH)α[L(IR)]2和Kandalian所得到的L(OH)α[L(IR)]1.38的结果之间.由于统计时所取的样本数最多,因此结果更能反映实际情况.进一步,可把这66个OH megamaser分为两类;第一类为L(OH)<102L(?)的小光度OH megamaser,小光度OH megamaser包含了14个OH megamaser;第二类为L(OH)≥102L的大光度OH megamaser,大光度OH megamaser包含了52个OHmegamaser.研究结果表明,小光度OH megamaser的光度和它们的宿主星系的红外光度之间相关关系为L(OH)α[L(IR)]1.43,与Kandalia所得到的结果相接近.大光度OH megamaser的光度和它们的宿主星系的红外光度之间的相关关系为L(OH)α[L(IR)]2,与Baan所得到的结果相一致. 展开更多
关键词 OH megamaser 光度 红外光度 宿主星系 相关关系 微波激射 星系 星际介质 宇宙脉泽
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Review of fully coherent free-electron lasers 被引量:19
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作者 Chao Feng Hai-Xiao Deng 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第11期214-228,共15页
Generation of intense, fully coherent radiation with wide spectral coverage has been a long-standing challenge for laser technologies. Several techniques have been developed in recent years to extend the spectral cove... Generation of intense, fully coherent radiation with wide spectral coverage has been a long-standing challenge for laser technologies. Several techniques have been developed in recent years to extend the spectral coverage in optical physics, but none of them hold the potential to produce X-ray laser pulses with very high-peak power. Urgent demands for intense X-ray light sources have prompted the development of free-electron lasers(FELs), which have been proved to be very useful tools in many scientific areas. In this paper, we give an overview of the basic principle of FELs, techniques for realizing fully coherent FELs, and the development of fully coherent FEL facilities in China. 展开更多
关键词 free-electron LASER Fully COHERENT Seeded FEL FEL OSCILLATOR
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Simplified nonlinear theory of the dielectric loaded rectangular Cerenkov maser 被引量:2
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作者 赵鼎 丁耀根 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第9期239-246,共8页
To rapidly and accurately investigate the performance of the dielectric loaded rectangular Cerenkov maser, a simplified nonlinear theory is proposed, in which the variations of wave amplitude and wave phase are determ... To rapidly and accurately investigate the performance of the dielectric loaded rectangular Cerenkov maser, a simplified nonlinear theory is proposed, in which the variations of wave amplitude and wave phase are determined by two coupled first-order differential equations. Through combining with the relativistic equation of motion and adopting the forward wave assumption, the evolutions of the forward wave power, the power growth rate, the axial wave number, the accumulated phase offset, and the information of the particle movement can be obtained in a single-pass calculation. For an illustrative example, this method is used to study the influences of the beam current, the gap distance between the beam and the dielectric surface, and the momentum spread on the forward wave. The variations of the saturated power and the saturation length with the working frequency for the beams with different momentum spreads have also been studied. The result shows that the beam wave interaction is very sensitive to the electron beam state. To further verify this simplified theory, a comparison with the result produced from a rigorous method is also provided, we find that the evolution curves of the forward wave power predicted by the two methods exhibit excellent agreement. In practical applications, the developed theory can be used for the design and analysis of the rectangular Cerenkov maser. 展开更多
关键词 Cerenkov maser dielectric load rectangular waveguide nonlinear theory
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Analysis of single frequency modulation for passive hydrogen maser 被引量:2
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作者 Hefei Zheng Jing Li +2 位作者 Wenming Wang Lianshan Gao Keming Feng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第4期661-668,共8页
Based on the theory of the passive hydrogen maser, along with the technology of frequency modulation and modulation transfer spectroscopy, the theoretical expression of the single frequency modulation for the passive ... Based on the theory of the passive hydrogen maser, along with the technology of frequency modulation and modulation transfer spectroscopy, the theoretical expression of the single frequency modulation for the passive hydrogen maser and the function of the cavity and H line error signals separation are derived, which are basically coincident with the experiment. The absorption and dispersion spectrum curves with different resonance widths show that the cavity and hydrogen transition serve as discriminators, and the two error signals can be separated. Through the calculations of the two error signals in the passive hydrogen maser, it analyzes the traditional method of the two error signals separation, and then describes a new improved method for the passive hydrogen servo loops consisting in the use of a single modulation frequency and frequency discrimination. A null interaction of the two error signals for the new selection of the phase setting is deduced theoretically and validated by the simulation. The preliminary experimental result confirms the feasibility of this new approach, which can reduce the influence from the cavity frequency variety on the crystal oscillator and contribute significantly to the long term performance of the passive hydrogen maser. 展开更多
关键词 passive hydrogen maser single frequency modulation frequency discrimination
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Infrared Characteristics of Associated Sources of Water Masers 被引量:2
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作者 Jarken Esimbek Yue-Fang Wu Jun-Zhi Wang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2005年第6期587-594,共8页
We present an analysis of the infrared properties of 1417 water masers collected from the literature published by December 2004. The associated infrared sources of the water masers were identified with IRAS and MSX (... We present an analysis of the infrared properties of 1417 water masers collected from the literature published by December 2004. The associated infrared sources of the water masers were identified with IRAS and MSX (Midcourse Space Experiment) catalogues. There are 1252 water masers associated with IRAS sources within 11, which include 700 interstellar and 552 stellar sources. For 382 sources, the IRAS counterpart identification and the maser classification are new. We found the colors of the interstellar maser sources are much redder than those of the stellar ones at IRAS wavelength bands; 99% of the interstellar maser sources are above black body line, while 95% of the stellar masers are below. The distribution difference of the two kinds of masers shown in the color-color diagram is due to their different optical depths and temperature distributions of dust regions. There are 743 water masers with MSX counterparts, of which 552 are interstellar masers and 191 are stellar masers. MSX colors of the associated sources of water masers are here analyzed for the first time. The color differences among the MSX bands are small and the interstellar masers are redder than the stellar masers. There is a correlation between the intensity of the stellar water maser emission and that of the 12μm and 25μm emissions, while there is no correlation between the water maser emission and the 8μm emission. The infrared intensity increases with increasing wavelength for the interstellar masers, while it is the opposite for stellar masers. These results may provide clues for the pumping of water maser and for the properties of the two kinds of maser emission regions. 展开更多
关键词 masers - ISM kinematics and dynamics - stars mass loss
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Picosecond terahertz pump-probe realized from Chinese terahertz free-electron laser 被引量:4
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作者 hao Wang Wen Xu +9 位作者 Hong-Ying Mei Hua Qin Xin-Nian Zhao Hua Wen Chao Zhang Lan Ding Yong Xu Peng Li Dai Wu Ming Li 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第8期127-132,共6页
Electron energy relaxation timeτis one of the key physical parameters for electronic materials.In this study,we develop a new technique to measureτin a semiconductor via monochrome picosecond(ps)terahertz(THz)pump a... Electron energy relaxation timeτis one of the key physical parameters for electronic materials.In this study,we develop a new technique to measureτin a semiconductor via monochrome picosecond(ps)terahertz(THz)pump and probe experiment.The special THz pulse structure of Chinese THz free-electron laser(CTFEL)is utilized to realize such a technique,which can be applied to the investigation into THz dynamics of electronic and optoelectronic materials and devices.We measure the THz dynamical electronic properties of high-mobility n-GaSb wafer at 1.2 THz,1.6 THz,and 2.4 THz at room temperature and in free space.The obtained electron energy relaxation time for n-GaSb is in line with that measured via,e.g.,four-wave mixing techniques.The major advantages of monochrome ps THz pump-probe in the study of electronic and optoelectronic materials are discussed in comparison with other ultrafast optoelectronic techniques.This work is relevant to the application of pulsed THz free-electron lasers and also to the development of advanced ultrafast measurement technique for the investigation of dynamical properties of electronic and optoelectronic materials. 展开更多
关键词 free-electron laser ultrafast measurements picosecond phenomena
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Transmission Probability of an Ultracold Three-Level Atom Through a Micromaser Cavity 被引量:2
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作者 ZHANG Zhi-ming ZHOU Shi-kang +2 位作者 XIA Yu-xing CHEN Ying-li XIE Sheng-wu 《Chinese Physics Letters》 SCIE CAS CSCD 1999年第8期568-570,共3页
The transmission probability of an ultracold cascade three-level atom through a micromaser cavity is calculated and analyzed. It is shown that the micromaser cavity can be used as a velocity selector for ultracold thr... The transmission probability of an ultracold cascade three-level atom through a micromaser cavity is calculated and analyzed. It is shown that the micromaser cavity can be used as a velocity selector for ultracold three-level atoms, and the velocity selectivity is better for three-level atoms than for two-level atoms. 展开更多
关键词 maser PROBABILITY SELECTIVITY
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Effect of normalized plasma frequency on electron phase-space orbits in a free-electron laser 被引量:2
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作者 吉驭嫔 王时建 +5 位作者 徐竟跃 徐勇根 刘晓旭 卢宏 黄小莉 张世昌 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第2期242-246,共5页
Irregular phase-space orbits of the electrons are harmful to the electron-beam transport quality and hence deteriorate the performance of a free-electron laser (FEL). In previous literature, it was demonstrated that... Irregular phase-space orbits of the electrons are harmful to the electron-beam transport quality and hence deteriorate the performance of a free-electron laser (FEL). In previous literature, it was demonstrated that the irregularity of the electron phase-space orbits could be caused in several ways, such as varying the wiggler amplitude and inducing sidebands. Based on a Hamiltonian model with a set of self-consistent differential equations, it is shown in this paper that the electron- beam normalized plasma frequency functions not only couple the electron motion with the FEL wave, which results in the evolution of the FEL wave field and a possible power saturation at a large beam current, but also cause the irregularity of the electron phase-space orbits when the normalized plasma frequency has a sufficiently large value, even if the initial energy of the electron is equal to the synchronous energy or the FEL wave does not reach power saturation. 展开更多
关键词 free-electron laser electron phase-space orbit normalized plasma frequency IRREGULARITY
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Vacuum Ultraviolet Free-Electron Laser Photoionization Mass Spectrometry of Alpha-pinene Ozonolysis 被引量:1
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作者 Xiangyu Zang Zhaoyan Zhang +10 位作者 Chong Wang Tiantong Wang Huijun Zheng Hua Xie Jiayue Yang Dongxu Dai Guorong Wu Weiqing Zhang Gang Li Xueming Yang Ling Jiang 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第2期281-288,I0002,共9页
α-pinene is the most abundant monoterpene that represents an important family of volatile organic compounds.Molecular identification of key transient compounds during theα-pinene ozonolysis has been proven to be a c... α-pinene is the most abundant monoterpene that represents an important family of volatile organic compounds.Molecular identification of key transient compounds during theα-pinene ozonolysis has been proven to be a challenging experimental target because of a large number of intermediates and products involved.Here we exploit the recently developed hybrid instruments that integrate aerosol mass spectrometry with a vacuum ultraviolet free-electron laser to study theα-pinene ozonolysis.The experiments ofα-pinene ozonolysis are performed in an indoor smog chamber,with reactor having a volume of 2 m^(3) which is made of fluorinated ethylene propylene film.Distinct mass spectral peaks provide direct experimental signatures of previously unseen compounds produced from the reaction ofα-pinene with O_(3).With the aid of quantum chemical calculations,plausible mechanisms for the formation of these new compounds are proposed.These findings provide crucial information on fundamental understanding of the initial steps ofα-pinene oxidation and the subsequent processes of new particle formation. 展开更多
关键词 Vacuum ultraviolet free-electron laser PHOTOIONIZATION Mass spectrometry Volatile organic compound OZONOLYSIS
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Two-Photon Micromaser with Initial Atomic Coherence
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作者 孙为辉 杜四德 陈效双 《Chinese Physics Letters》 SCIE CAS CSCD 2005年第11期2812-2815,共4页
We investigate the quantum dynamics of a two-photon micromaser pumped by atoms injected in the superposition state of the upper and intermediate levels. We simulate a master equation governing the system by the Monte ... We investigate the quantum dynamics of a two-photon micromaser pumped by atoms injected in the superposition state of the upper and intermediate levels. We simulate a master equation governing the system by the Monte Carlo wavefunction approach and analyse the steady-state behaviour as a function of the atomic transit time. The atomic coherence can effectively enhance the intensity and sub-Poissonian of the cavity field as compared with the atomic mixture. It is also discovered that the phase of the cavity field can be shifted by adjusting the detuning between the atom and field. This result shows that it is possible to manipulate the phase of the cavity field by detuning, due to atomic coherence. 展开更多
关键词 PHOTON STATISTICS QUANTUM STATES maser
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Extragalactic H_2O Megamaser Sources:Central Black Holes,Nuclear X-ray and Maser Emissions 被引量:2
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作者 Jiang-Bo Su Jiang-Shui Zhang Jun-Hui Fan 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第5期547-554,共8页
Extragalactic H2O megamasers are typically found within the innermost few parsecs of active galaxy nuclei (AGN) and the maser emission is considered to be excited most likely by the X-ray irradiation of the AGN. We ... Extragalactic H2O megamasers are typically found within the innermost few parsecs of active galaxy nuclei (AGN) and the maser emission is considered to be excited most likely by the X-ray irradiation of the AGN. We investigate a comprehensive sample of extragalactic H2O masers in a sample of 38 maser host AGN to check potential correlations of the megamaser emission with parameters of the AGN, such as X-ray luminosity and black hole (BH) masses. We find a relation between the maser luminosities and BH masses LH2O∝MBH^3.6±0.4 which supports basically the theoretical prediction. The relation between the maser emission and X-ray emission is also confirmed. 展开更多
关键词 galaxies active -galaxies nuclei -masers
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Technology and test results of space adaptability of passive hydrogen maser
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作者 Hefei Zheng Lianshan Gao +4 位作者 Keming Feng Jing Li Wenming Wang Chunyan Cao Jihong Zhang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第2期251-256,共6页
Based on the operating principle and the electric property design of the passive hydrogen maser, the technology and test results of its space adaptability are carried out under the special launch conditions and space ... Based on the operating principle and the electric property design of the passive hydrogen maser, the technology and test results of its space adaptability are carried out under the special launch conditions and space environment. The various perturbations affecting the output frequency of such a standard used for the navigation satellite system are specified, such as magnetic field change, vibration, thermal vacuum and radiation. Through the adaptability technology in the aspects above, the security and reliability of the space passive hydrogen maser sufficiently fulfill the requirements of space operation. At present, the space passive hydrogen maser is working normally on board, indicating that the space adaptability satisfies the design requirement. 展开更多
关键词 passive hydrogen maser SPACE ADAPTABILITY performance test
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The potential of FAST in detecting celestial hydroxyl masers and related science topics
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作者 Jiang-Shui Zhang Di Li +2 位作者 Jun-Zhi Wang Qing-Feng Zhu Juan Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第2期65-70,共6页
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will make contributions to studies of Galactic and extragalactic masers. This telescope, with construction finished and now undergoing commissioning, has... The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will make contributions to studies of Galactic and extragalactic masers. This telescope, with construction finished and now undergoing commissioning, has an innovative design that leads to the highest sensitivity of any single dish radio telescope in the world. FAST's potential for OH megamaser research is discussed, including the sky density of masers detectable in surveys. The scientific impact expected from FAST maser studies is also discussed. 展开更多
关键词 maserS instrumentation:sensitivity instrumentation:detectability SKY density galaxies:interactions
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A search for massive young stellar objects with 98 CH_3OH maser sources
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作者 Tie Liu Yue-Fang Wu Ke Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2010年第1期67-82,共16页
Using the 13.7 m telescope of the Purple Mountain Observatory (PMO), a survey of the 3 = 1 - 0 lines of CO and its isotopes was carried out on 98 methanol maser sources in January 2008. Eighty-five sources have infr... Using the 13.7 m telescope of the Purple Mountain Observatory (PMO), a survey of the 3 = 1 - 0 lines of CO and its isotopes was carried out on 98 methanol maser sources in January 2008. Eighty-five sources have infrared counterparts within one arcmin. In the survey, except for 43 sources showing complex or multiple-peak profiles, almost all the ^13CO line profiles of the other 55 sources have large line widths of 4.5km s^-1 on average and are usually asymmetric. Fifty corresponding Infrared Astronomical Satellite (IRAS) sources of these 55 sources have Lbdl larger than 10^3 L⊙, which can be identified as possible high-mass young stellar sources. Statistics show that the ^13CO line widths correlate with the bolometric luminosity of the associated IRAS sources. Here, we also report the mapping results of two sources; IRAS 06117+1350 and IRAS 07299-1651. Two cores were found in IRAS 06117+1350 and one core was detected in IRAS 07299-1651. The northwest core in IRAS 06117+1350 and the core in IRAS 07299-1651 can be identified as precursors of UC HII regions or high-mass protostellar objects (HMPOs). The southeast core of IRAS 06117+1350 has no infrared counterpart, seeming to be at a younger stage than the pre-UC HII phase. 展开更多
关键词 STARS formation -- ISM clouds -- ISM methanol maser
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Analysis and design of the taper in metal-grating periodic slow-wave structures for rectangular Cerenkov masers
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作者 陈晔 赵鼎 +1 位作者 王勇 舒雯 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期662-668,共7页
The hybrid-mode dispersion equation of the metal-grating periodic slow-wave structure for a rectangular Cerenkov maser is derived by using the Borgnis function and field-matching methods.An equivalent-circuit model fo... The hybrid-mode dispersion equation of the metal-grating periodic slow-wave structure for a rectangular Cerenkov maser is derived by using the Borgnis function and field-matching methods.An equivalent-circuit model for the taper of the groove depth that matches the smooth waveguide to the metal-grating structure is proposed.By using the equivalentcircuit method,as well as the Ansoft high frequency structure simulator(HFSS) code,an appropriate electromagnetic mode for beam-wave interaction is selected and the equivalent-circuit analysis on the taper is given.The calculated results show that a cumulative reflection coefficient of 0.025 for the beam-wave interaction structure at a working frequency of 78.1 GHz can be reached by designing the exponential taper with a TE z10 rectangular waveguide mode as the input and the desired TE x10 mode as the output.It is worth pointing out that by using the equivalent-circuit method,the complex field-matching problems from the traditional field-theory method for taper design can be avoided,so the taper analysis process is markedly simplified. 展开更多
关键词 rectangular Cerenkov maser Borgnis function method equivalent-circuit method HFSS TAPER
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PLASMA-FILLED DIELECTRIC CHERENKOV MASER WITH A LONGITUDINAL MAGNETIC FIELD
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作者 Wu Jianqiang Song Liqun Liu Shenggang (University of Electronic Science and Technology of China, Chengdu 610054) 《Journal of Electronics(China)》 1996年第3期249-256,共8页
The use of a background plasma in a dielectric Cherenkov maser can effectively increase the efficiency and the microwave output power of the device. Here, the effect of the longitudinal uniform magnetic field on the w... The use of a background plasma in a dielectric Cherenkov maser can effectively increase the efficiency and the microwave output power of the device. Here, the effect of the longitudinal uniform magnetic field on the wave-beam interaction of the plasma-filled dielectric Cherenkov maser is examined by solving the beam-plasma, dielectric lined waveguide dispersion equation. And the effects of the longitudinal magnetic field, plasma density and dielectric parameters on the linear spatial growth rate and the energy ratio are presented. 展开更多
关键词 Longitudinal MAGNETIC field PLASMA DIELECTRIC CHERENKOV maser
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Research on frequency-temperature compensated sapphire-SrTiO_3 loaded cavity for hydrogen maser
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作者 Wang Nuanrang Zhou Tiezhong +2 位作者 Gao Lianshan Yang Chuntao Feng Keming 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第4期711-717,共7页
To obtain frequency-temperature compensation in a sapphire loaded cavity for hydrogen maser, a dielectric named SrTiO3 is employed whose temperature coefficient of permittivity is opposite to that of sapphire. Based o... To obtain frequency-temperature compensation in a sapphire loaded cavity for hydrogen maser, a dielectric named SrTiO3 is employed whose temperature coefficient of permittivity is opposite to that of sapphire. Based on theoretical analysis and computer simulation, a TE011 mode of a sapphire loaded cavity associated with two small rings of SrTiO3 with different thickness is solved, and the useful parameters that influence the temperature coefficient of cavity are calculated. Finally an experiment is brought forward and its results are very close to the computing results. When the thickness of SiTiO3 dielectric is 7 mm and the diameter is 17 mm in configuration b, the temperature coefficient of cavity is decreased from -58.8 kHz/K to -8.2 kHz/K and the quality factor is 40248. 展开更多
关键词 atomic hydrogen maser frequency-temperature compensation sapphire loaded cavity temperature coefficient.
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