强流回旋加速器射频功率源末级谐振放大器的研制

为适应强流回旋加速器综合实验装置强流束调束需求,开展了对射频系统中功率源的末级谐振放大器的研制。功率源末级谐振放大器采用阴极驱动模式的三级真空电子管作为核心放大器件,充分地考虑了输入阻抗、输出调谐和输出耦合的调节需求,通过射频电路仿真和三维电磁场仿真等手段实现了对末级谐振放大器各参数的仿真。网络分析仪对末级谐振放大器的各项参数的测量表明:制造结果与设计参数高度一致;示波器对末级谐振放大器进行实验测试表明:8h假负载考验中功率稳定度好于1%,输出效率达70%,可为强流回旋加速器综合实验装置强流束调试提供射频功率的技术支持。     

中国先进研究堆功率调节系统的仿真研究及优化设计

基于核电厂SimPort仿真平台构建了中国先进研究堆(CARR)功率调节系统仿真模型,利用该模型对CARR功率调节系统进行了瞬态仿真研究;针对CARR功率调节系统驱动机构的特点,研究了控制棒位移精度以及电磁线圈和衔铁位移延迟对系统稳定性的影响.综合考虑CARR系统的工艺要求和功率控制系统的功能及特点,得到了数字控制器的整定参数和控制棒驱动机构的稳定限值:数字控制器的采样周期T=100ms,比例增益KP=300;控制棒位移精度的稳定限值为0.4mm,电磁线圈和衔铁的稳定限值为6.0mm.     

25kW高频功率源末级腔体的模拟计算

用于加拿大TRIUMF国家实验室的1台25kW高频功率源的末级腔体结构如图1所示，该末级腔体的设计频率约为23MHz，短路端由簧片与外导体连接，作为腔体频率粗调的机构。由于高频功率源本身空间结构的限制，要减小末级腔体的长度，采取了增加腔体电容值的方法，     

反应堆功率控制半实物仿真系统

对于新型研究堆,其功率自动调节系统的设计缺乏基本的设计参数和依据,需要通过半实物仿真试验对功率自动控制系统的控制参数和性能进行研究.半实物仿真系统是一个半实物的反应堆闭环控制系统.它根据当前功率与给定功率的偏差执行功率调节算法,输出步进电机控制信号,使步进电机正、反向转动,以此达到功率调节作用.通过在半实物仿真系统上进行的各种控制方式的闭环运行试验得到结论:需根据不同的棒位区域取不同的控制器参数,才能够较好地满足预定的控制指标和性能要求,为新型研究堆功率自动调节系统的设计及闭环运行提供理论依据和技术基础.     

脉冲堆功率调节系统仿真研究

用自主研制开发的脉冲堆功率调节系统仿真程序研究了脉冲堆功率调节系统的动态特性,并用计算得到的方波特性与脉冲堆的实测结果进行了比较,两者具有良好的一致性。     

核反应堆功率调节系统控制特性研究

某新型研究堆采用新型燃料元件和堆芯结构，反应堆的控制特性缺乏基本数据，功率调节系统的设计无可借鉴经验。通过半实物仿真试验，在同一功率定值下分别引入阶跃和斜坡反应性扰动，考虑调节棒在不同位置的价值影响，采用PD控制方案研究功率调节系统的调节特性和控制效果，并对控制方案和PD参数进行比较和优化，为反应堆功率调节系统的设计和投入运行奠定基础。半实物仿真试验结果表明：采用同一组控制器参数，无法满足预定的控制要求。充分发挥数字化控制器的优点，在同一功率定值、不同棒位下，采用不同的控制器参数能较好地满足预定的控制指标和性能要求。     

固态功率源功放模块反射功率过荷分析

中国加速器驱动次临界系统(Chinese Accelerator Driven Sub-critical System,C-ADS)注入器II超导直线加速器采用固态功率源驱动常温加速结构和超导腔,运行中出现了功率源的功放模块因反射功率过荷而损坏的现象。为此研究了反射功率在模块间的分配与功率合成网络S参数以及模块输出状态的关系。结果表明:如果个别功放模块无功率输出,合成失衡会导致反射功率在模块间的不平衡分布,部分模块承受的反射功率将超过其实际承受能力。对于一级合成的功率源,只有失效模块承受的反射功率可能超限;对于多级合成的功率源,失效模块以及同一合成支路的正常模块均存在反射功率过荷的可能性。     

西安脉冲堆方波运行功率调节方法研究

本文建立了数字化功率调节系统在方波运行下的自动控制方法,提出了新的功率调节系统投入时刻设计方案,给出了调节棒初始棒位和发射脉冲棒后堆芯正反应性大小的建议,设计了数字化系统的方波运行功率调节方法,使用西安脉冲堆仿真程序XPRSC对设计方法进行了优化和验证。结果表明,该方法可实现更宽定值功率范围内的方波运行,能为堆上试验提供理论指导。     

实验反应堆功率调节系统PID控制器的解析设计方法

通过对实验反应堆系统模型进行线性化和模型降阶、再对降阶模型进行PID控制器的理论设计的方法，可使反应堆功率调节系统的设计最优化、客观化和解析化。将此解析化方法应用于—实验反应堆功率调节系统的设计，通过数值仿真证明：设计的控制器控制效果良好，该解析化设计方法可行?     

脉冲堆功率调节系统动态特性分析

脉冲堆功率调节系统动态特性的分析,对调节系统的优化设计很重要,对脉冲堆功率调节系统的调试和运动也很有参考价值。本文给出了脉冲堆功率调节系统动态特性仿真结果,并给予简要分析。     

CsI(Tl)闪烁探测器读出电路设计

介绍了配置于新型γ能谱仪的CsI(Tl)闪烁探测器的读出电路设计。输入缓冲级采用折叠嵌位电路,改善了系统频率特性并提高了输入阻抗;放大级采用自举电路,改善了系统动态性能并提高了开环增益;输出级采用电流源负载电路,改善了输出信号的线性度并增强了系统的稳定性。实验表明:读出电路噪声为51.08 f C+1.97 f C/p F,时间漂移为0.112%,探头对137Cs源γ射线的输出信号信噪比可达23:1,能量分辨率可达4.98%。     

Integrated low-noise low-power fast charge-sensitive preamplifierfor avalanche photodiodes in JFET-CMOS technology

To take advantage of the compactness of avalanche photodiode (APD) arrays, low-noise power-efficient fast charge-sensitive preamplifier chips with differential current drivers have been developed. A 16-channel and a single-channel version are available. The chips were adapted for low-capacitance 4×8 APD arrays produced by Hamamatsu, Japan. A mixed junction field-effect transistor (JFET)-CMOS production process yielded high-quality integrated JFETs for the input stage of the amplifier's folded cascade. Thus, the 1/f-noise corner is kept at 4 kHz. The JFET has a transconductance of 11 mS at a drain current of 3 mA. The serial noise of the input transistor was found to be 0.8 nV/√(Hz). The signal rise time of the driver outputs is 20 ns. The rms noise of the preamplifier was found to be 480 e^- with a 25 e^- /pF noise slope for a shaping time of 50 ns. The serial input noise of the preamplifier is about 1.4 nV/√(Hz) from 200 kHz up to 40 MHz, and the 1/f-noise corner is at 70 kHz. The power consumption is 30 mW per preamplifier, including the differential driver. The linearity is better than 1.3% over 48 dB dynamic range. For the 16-channel chip, the channel-to-channel gain variation is less than 3.5%. Performance similar to photomultiplier tubes can be achieved with APDs in combination with this integrated preamplifier chip     

Improvement of circuit oscillation generated by underwater high voltage pulse discharges based on pulse power thyristor

High voltage fracturing technology was widely used in the field of reservoir reconstruction due to its advantages of being clean, pollution-free, and high-efficiency. However, high-frequency circuit oscillation occurs during the underwater high voltage pulse discharge process, which brings security risks to the stability of the pulse fracturing system. In order to solve this problem, an underwater pulse power discharge system was established, the circuit oscillation generation conditions were an...     

CSNS/RCS谐振电源系统输出特性模拟研究

对于快循环同步加速器谐振电源系统而言,负载磁铁、电抗器会产生极高的感应电压,实际工作中不具备测量条件。本文利用仿真软件,观测设备对地电压变化情况,验证电源与负载连接方式的合理性。此外,激励源为受控电流源,电源输出特性集中体现为输出电压的变化,在电感非线性变化不能忽略的情况下,本文通过搭建的仿真模型,寻找负载谐振单元内电容匹配方案,优化电源输出特性,并利用实际测量数据验证模型的可靠性以及分析的可行性。     

1 MV杆箍缩二极管辐射特性实验研究

依据现有的实验室驱动源能力建立杆箍缩二极管（RPD）粒子模拟计算模型,获得了工作电压为1 MV的RPD电参数特性及电子、离子时空分布特性,并设计了RPD实验装置。在1 MV驱动源平台上开展了实验研究,实验中采用B dot、D dot、热释光剂量片和SiPin二极管测试了RPD电流、电压、辐射剂量和光脉冲信号,分析了RPD电参数及X射线辐射特性。结果表明,阳极采用1.5 mm钨时,1 MV电压下1 m处辐射剂量约1 R,并得出剂量与电压Ud、电流Id的关系式D(R=1 m)=120U1.55d∫Iddt;二极管阻抗范围为26.4~36.7 Ω,空间电荷限制阶段平均阻抗下降率大于2 Ω/ns,磁绝缘阶段平均阻抗下降率小于0.5 Ω/ns;光脉冲宽度较电压脉冲宽度约缩短20%~30%,与电压、电流的关系为∝IdU1.55 d。实验测试的剂量和光脉冲信号结果与拟合计算式计算结果符合较好。     

ASD IC for the thin gap chambers in the LHC Atlas Experiment

An amplifier-shaper-discriminator (ASD) chip was designed and built for Thin Gap Chambers in the forward muon trigger system of the LHC Atlas experiment. The ASD IC uses SONY Analog Master Slice bipolar technology. The IC contains 4 channels in a QFP48 package. The gain of its first stage (preamplifier) is approximately 0.8 V/pC and output from the preamplifier is received by a shaper (main-amplifier) with a gain of 7. The baseline restoration circuit is incorporated in the main-amplifier. The threshold voltage for discriminator section is common to the 4 channels and their digital output level is LVDS-compatible. The IC also has analog output of the preamplifier. The equivalent noise charge at input capacitance of 150 pF is around 7500 electrons. The power dissipation with LDVS outputs (100 Ω load) is 59 mW/ch     

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.     

Design,simulation and construction of the Taban tokamak

This paper describes the design and construction of the Taban tokamak, which is located in Amirkabir University of Technology, Tehran, Iran. The Taban tokamak was designed for plasma investigation. The design, simulation and construction of essential parts of the Taban tokamak such as the toroidal field(TF) system, ohmic heating(OH) system and equilibrium field system and their power supplies are presented. For the Taban tokamak, the toroidal magnetic coil was designed to produce a maximum field of 0.7 T at R?=?0.45 m. The power supply of the TF was a130 kJ, 0–10 kV capacitor bank. Ripples of toroidal magnetic field at the plasma edge and plasma center are 0.2% and 0.014%, respectively. For the OH system with 3 kA current, the stray field in the plasma region is less than 40 G over 80% of the plasma volume. The power supply of the OH system consists of two stages, as follows. The fast bank stage is a 120 μF, 0–5 k V capacitor that produces 2.5 kA in 400 μs and the slow bank stage is 93 mF, 600 V that can produce a maximum of 3 kA. The equilibrium system can produce uniform magnetic field at plasma volume. This system's power supply, like the OH system, consists of two stages, so that the fast bank stage is 500 μF, 800 V and the slow bank stage is 110 mF, 200 V.     

Theory on dynamic matching with adjustable capacitors for the ICRF system of ASDEX Upgrade

The coupling of electromagnetic waves in the Ion Cyclotron Range of Frequencies (ICRF) is an important method to heat magnetically confined plasmas. Changing plasma conditions, which originate from processes like L-mode to H-mode transition or gas puffing, vary the load impedance of the ICRF antennas. To optimize the power transfer from the radio frequency (RF) generators to the antennas and consequently to the plasma, as well as to protect the RF sources against too high reflected power, a system that matches (i.e. transforms) the antenna input impedance to the impedance required by the generator is necessary. At ASDEX Upgrade this matching system consists of two stub tuners for each antenna, which match the antenna impedance for a value preset before the discharge. The length of the stubs cannot be changed fast enough to compensate plasma variations even on the moderate timescale of the confinement time in ASDEX Upgrade. The use of 3 dB-couplers allows operation even with varying load, at the cost of a reduced power to the plasma.When adjustable capacitors are applied in parallel to the stubs, dynamic matching becomes possible on the tens of ms timescale. The paper describes first the calculation of the required capacitance using transmission line theory. In a second model a minimum search algorithm finds, for a given antenna impedance, the length of the stubs needed for matching, now including the initial values of the capacitors. For the chosen pre-match point in the Smith chart, the range of impedances around this point is calculated for which the voltage standing wave ratio (VSWR) can be lowered below a minimum value by readjusting the capacitors within their maximum and minimum values. The matching range is thereby significantly larger than without the application of adjustable capacitors, at least with a frequency of 30 MHz and 36.5 MHz.     

三支节液态调配器ICRH时的阻抗匹配分析

基于传输线理论,采用三支节液态调配器以达到托卡马克离子回旋共振加热(ICRH)时射频源和天线负载间的阻抗匹配。分析了其阻抗匹配过程,并根据阻抗匹配条件得到天线输入阻抗变化时,三支节液态调配器的优化调配参数。利用数值模拟验证了在其他实验参数相同的条件下,三支节液态调配器的优化调配参数能使天线系统获得良好的匹配状态。