2 MeV自屏蔽消毒灭菌装置微波系统研制

微波系统是自屏蔽消毒灭菌装置的关键部件之一。它包括微波的产生、传输、监测以及保证系统稳定工作的充气装置。 采用M5125型磁控管作为高功率微波信号源,工作频率为2998MHz,输出脉冲功率2MW,平均功率2kW,经过方圆转换波导、弯波导、四端环行器、抽气波导和波导窗后,由加速管输入耦     

6 MeV无损探伤电子直线加速器微波系统研制

微波系统是无损探伤电子直线加速器的重要组成部件之一。它包括微波的产生、传输、监测以及保证系统稳定工作的充气装置和自动频率控制装置。 MG5193型磁控管工作频率2998MHz,输出脉冲功率2.6MW,平均功率2.6kW,经过方圆转     

9MeV无损探伤电子直线加速器微波系统研制

微波系统是无损探伤加速器的重要部件之一,它产生频率2 998 MHz、脉冲功率2.6 MW的射频信号,并经传输波导馈入加速管,在加速管内形成驻波电磁场,加速电子到能量9 MeV。 为了保证磁控管稳定工作和运行,采用高功率四端环行器隔离加速管的反射,采用紧凑型定向耦合器分别对入射与反射的射频信号取样,监测功率电平、频率与微波包络波形,同时为自动频率控制装置提供鉴相信号,使磁控管工作频率自动跟踪加速管的谐振频率,从而获得稳定的能量与最大剂量率输出。波导系统充入0.18 MPa的六氟化硫,防止射频电击穿,提高系统运行的稳定性。该系统提供…     

铷原子频标物理部分改进

本文对星载铷原子频标物理部分进行技术改进。改善磁控管微波腔的结构,使信噪比得到了提高;优化了物理部分光路系统,使光电探测信号强度提高了25%。此外,通过Ansoft HFSS仿真软件建立了微波腔的模型,对腔内场型分布和谐振频率进行了仿真,数字仿真和性能测试显示这种微波腔的谐振模式为TE₀₁₁模式,且拥有较大的质量因子。最后,对改进后的铷原子频标系统进行了初步测试,发现短期稳定度达到了6.0×10^-13τ^-1/2（τ为取样时间）。研究结果表明,改进后的物理部分满足铷原子频标的研制需求,适合应用于高性能的星载铷原子频标。     

C波段9 MeV驻波电子直线加速管设计

介绍了C波段驻波电子直线加速管的研制情况.该加速管采用2.5 MW脉冲磁控管为微波功率源,脉冲宽度4μs,重复频率250 MHz.可提供能量为6 MeV和9 MeV两档能量的电子束,工作频率为5712 MHz,管长约620 mm.通过调节加速管的入口功率、电子枪的注入电压实现加速管的输出能量两挡调变.     

强流中子管微波离子源微波吸收效率的实验研究

强流中子管微波离子源实验系统已建成。给出磁场模式设计结果,通过实验确定微波吸收效率与磁场分布及气压的关系,其中微波输入功率300-500W。微波引入窗处的磁场为0.095T时,微波吸收效率都在90%以上,最高达到100%。     

新型驻波加速器用恒温水冷系统的研制

驻波加速器系统中需要恒温水冷系统冷却。恒温的部件有加速管管体、靶、微波窗、磁控管、四端环流器、三端负载等。恒温水冷系统主要为加速管和微波系统提供循环冷却水，以保持磁控管的频率跟踪加速管的频率并冷却微波系统的元件。恒温水冷系统分为循环水系统及制冷系统，根据安装位置及环境，可选分体式或一体式。     

数字化I/Q技术用于磁控管频率控制

采用磁控管做功率源的低能电子直线加速器在医疗、辐照、X射线检测等领域得到较为广泛的应用。磁控管产生的微波信号输入到加速管,对电子束进行加速,磁控管的工作频率稳定性对加速器电子束能量、能散及发射度产生直接的影响。但磁控管是一种振荡器,其频率受到温度、振动、负载牵引的影响会产生漂移,所以需要一套自动频率控制系统(Automatic Frequency Control,AFC)机构对磁控管进行频率控制。目前普遍采用的AFC机构主要是行波控相或双腔鉴频,对两路检波信号差分放大进而控制伺服电机进行调谐的方法实现磁控管的频率稳定。随着数字化I/Q和FPGA(Field-Programmable Gate Array)技术的不断发展,运用该技术进行磁控管的频率控制完全具备可行性。本文从理论和工程设计上阐述了数字化I/Q技术在磁控管频率控制上的应用。     

小型无损探伤电子直线加速器BP神经网络稳频系统

作为小型探伤电子直线加速器功率源的磁控管 (工作频率为 93 70MHz) ,其主要缺点是自身振荡频率的稳定性差 ,且磁控管在工作中由于各种原因会产生打火、跳谱和散谱现象 ,从而造成加速器工作不稳定 ,因此 ,必须采用频率稳定系统。为了更好地解决上述问题 ,应用BP神经网络方法 ,以保证工作频率稳定。     

美国加热等离子体用的高功率射频源

【美国《原子能消息周刊》1980年4月7日报道】美国能源部宣布,一种新的射频源创造了频率为2,800兆赫时连续的功率水平达到212千瓦的新纪录。这种新的射频源将为等离子体聚变试验提供微波加热源。新射频源叫“陀螺振子”(gyrotron),其转换效率为41%,频率为2,800兆赫,其     

Mode filtering based on ponderomotive force nonlinearity in a plasma filled rectangular waveguide

Here a new scheme for mode filtering is proposed.Based on the ponderomotive force effect,propagation of the microwave dual-mode through a plasma-filled metallic rectangular waveguide is investigated.To excite the TE20 mode in a rectangular waveguide,the existence of fundamental modes is unavoidable.To filter the destructive mode (TE10),the waveguide is filled with a collisional plasma.Based on the coupling effect,the energy of this destructive TE10 mode is transferred to the TE20 mode.The proposed structure acts like a mode convertor.The TE10 mode become more attenuated and instead the TE20 mode is amplified.The plasma filled rectangular waveguide acts as a mode filtering tool.     

电子回旋自共振加速器输出能量的影响因素及优化

回旋自共振加速器（CARA）加速效率高，在低能、大功率电子束领域具有非常好的应用前景。由于加速腔浸没在螺线管磁场中，电子束在轴向静态磁场的约束下螺旋前进，与加速腔中的TE₁₁模微波场保持同步而被横向持续加速。但加速器的输出能量并不随加速过程递增，而是与电子束的注入能量、轴向静态磁场、加速腔波导长度及微波场强度等多个相互约束的参数相关。本文从理论上分析了相关参数对输出能量的影响，利用三维电磁场仿真软件CST及粒子跟踪程序分别研究了相关参数对输出电子束状态的约束关系，并对这些参数进行联合优化，使得电子输出能量达到设计值。     

Effect of Plasma Density on Proton Acceleration in a Rectangular Waveguide

Analytical studies are made for the proton acceleration during its motion in thefields of the fundamental mode excited by a high-intensity microwave in a rectangular waveguide,when the proton is injected along the propagating direction of the mode. The trajectory of theproton is calculated and the expressions are obtained for the energy gain and acceleration gradienttogether with the effects of plasma density, microwave frequency and waveguide width. Energygain of 181 keV is attained by a 50 keV proton in a 0.015m×0.020 m evacuated waveguide when0.5×10～(10)W/m～2 microwave intensity is used. However, this gain increases to 1387 keV whenthe waveguide is filled with a plasma having a density of 1.0×10～(19) m～(-3). Higher accelerationgradients are achieved when the proton is injected with a higher initial energy and also when themicrowave intensity increases. The effects of the microwave frequency and width of the waveguideare found to decrease the acceleration gradient.     

The Design of an Elliptical Reflector in the Gaussianlike Antenna Used in HT-7 ECRH System

The structure of the antenna which will be used in HT-7 tokamak electron cyclotron resonance heating (ECRH) experiment and the desgn of its key component (the elliptical reflector) were introduced ,A quasi-Gaussian TE11 wave sent from the TE01-TE11 mode converter was reflected by two mirrors from the waveguide aperture to the plasma center area.One of the two mirrors is a plane mirror and the ather is an elliptical mirror,In this process,the wave beam will be converged by the two reflecting mirrors and the emissive direction of the wave is also controlled by bhem .As requested physically for ECRH experiment the arrangenent of the two mirrors can ensure the wave to be launced from the low-field side of the toure.     

Design of the Transmission Lines for 140 GHz ECRH System on HL-2A

A new 140 GHz/2 MW/3 s electron cyclotron resonance heating （ECRH） system composed of two units is now being constructed on HL-2A. As a part of the system, two trans- mission lines marked No.7 ＆ 8 play the role of carrying microwave power from two gyrotrons to the tokamak port. Based on the oversized circular corrugated waveguide technology, an evacu~ ated transmission system with high power capability and high transmission efficiency is designed. Details are presented for the design of the corrugated waveguide, the layout of the proposed lines and the vacuum pumping system. Then mode conversion losses due to coupling, misalignment, bends and gaps are discussed to serve as a reference for analyzing the transmission efficiency and alignment. Finally, a dual-modes propagation case consisting of the HEll and LPn even modes is discussed.     

Results of ICRF Heating Experiments from the EAST 2010 Campaign

Radio frequency(RF) plasma heating in ion cyclotron range of frequencies(ICRF)was successfully performed on the Experimental Advanced Superconducting Tokamak(EAST).This is mainly because lithium wall conditioning was routinely used to reduce both impurity and hydrogen(H) recycling and to improve the ICRF power absorption.Mainly ICRF heating of the H minority regime at 27 MHz has been applied in deuterium plasmas.The ion cyclotron resonance heating(ICRH) is found to depend strongly on plasma preheating.The ICRH efficiency can be much improved in conjunction with the lower hybrid wave(LHW).Effective ion and electron heating was observed with the H minority heating mode.The increase of the stored energy reached30 kJ in L-mode plasma by using the ICRF power of 1.0 MW alone when the H cyclotron resonance layer was at plasma center.     

325 MHz高功率波导窗设计研究

为了使漂移管加速结构运行更加稳定，传输功率可更好地馈入质子直线加速器中，本文对漂移管加速结构的波导窗进行设计与研究。利用微波仿真软件CST对波导窗的结构进行计算，并通过改善匹配结构对射频参数进行分析及优化。通过仿真结果计算频率带宽、电场分布及功率损耗。最终对波导窗进行热分析，通过公式计算所需冷却水的流量。结果表明，该波导窗可应用于325 MHz加速结构中。     

高平均束流功率辐照加速器加速结构的研究

本文介绍了10 MeV/100 kW的高平均束流功率工业辐照加速器束流动力学模拟结果及其加速结构的优化设计结果。加速器采用驻波双周期轴耦合结构,1个加速腔和1个耦合腔构成1个加速单元,其工作频率为325 MHz,工作模式为π/2,加速腔和耦合腔之间通过耦合狭缝在轴向以磁耦合的方式耦合在一起。使用SUPERFISH优化加速腔的有效分路阻抗、Kilp系数等关键参数。束流动力学方面,使用PARMELA模拟论证在粒子源提供2.5 keV、500 mA的电子束后,通过6个加速腔可得到10 MeV/100 kW的平均束流功率。加速腔优化完成后使用CST对耦合腔进行了设计,此时由6个加速单元组成的加速结构有效分路阻抗为23.9 MΩ/m、无载品质因数为29 347,各加速腔与相邻的耦合腔耦合系数为4.7%,工作模式与其相邻模式的最小频率间隔为2 MHz,每个加速单元功耗为290 kW。     

Detection and Mode Identification of Axial Cracks in the Steam Generator Tube of the Nuclear Power Plant Using Ultrasonic Guided Wave

For those people who are involved in NDE, there is a growing concern regarding the significant traveling distance of a guided wave in a structure, which ensures the inspection of a large area of the structure from a single location. A significant number of studies on the guided wave have therefore been made to apply the foregoing to a nondestructive evaluation in many different industries and resulted in an increase in the efficiency of practical guided wave inspection. Unlike the previous studies based mainly on the detection of circumferential flaws, this study is focused on the axial flaw detection in the steam generator tubes of Korean standard nuclear power plants by generating the guided wave by changing frequency and selecting the applicable mode from the dispersion curve for the steam generator tube calculated in this study, where the dispersion-based short-time Fourier transform (D-STFT) algorithm is used to enhance mode identification. In conclusion, the L (0,1) mode at 2.25MHz is found to be most sensitive in detecting axial flaws in a steam generator tube.     

Power Compensation for ICRF Heating in EAST

The source system covering a working frequency range of 24 MHz to 70 MHz with a total maximum output power of 12 MW has already been fabricated for Ion Cyclotron Range of Frequency(ICRF) heating in EAST from 2012. There are two continuous wave(CW) antennas consisting of four launching elements each fed by a separate 1.5 MW transmitter. Due to the strong mutual coupling among the launching elements, the injection power for launching elements should be imbalance to keep the k||(parallel wave number) spectrum of the launcher symmetric for ICRF heating. Cross power induced by the mutual coupling will also induce many significant issues,such as an uncontrollable phase of currents in launching elements, high voltage standing wave ratio(VSWR), and impedance mismatching. It is necessary to develop a power compensation system for antennas to keep the power balance between the feed points. The power balance system consists of two significant parts: a decoupler and phase control. The decoupler helps to achieve ports isolation to make the differential phase controllable and compensate partly cross power. After that, the differential phase of 0 or π will keep the power balance of two feed points completely. The first power compensation system consisting of four decouplers was assembled and tested for the port B antenna at the working frequency of 35 MHz. With the application of the power compensation system, the power balance, phase feedback control, and voltage standing wave ratio(VSWR) had obviously been improved in the 2015 EAST campaign.