基于积分束流变压器的加速器束团电荷量测量系统

 为满足清华大学加速器实验室光阴极微波电子枪实验平台的发展需求,设计了束团电荷量测量系统,可以实现实时测量加速器束团电荷量的目标。这套测量系统基于积分束流变压器,包括前置放大器、门控积分器、模数转换和数据传输模块。利用信号发生器模拟束流,对整套系统进行了离线测量实验。当前置放大器放大倍数取200和20时,AD转换值和束流电荷的比值分别为2.181 PC-1和0.195 PC-1,与理论值2.070 PC-1和0.207 PC-1基本吻合;其对应的电荷量测量误差分别小于2 PC和15 PC。测量结果和模拟束流电荷量值的拟合曲线线性度好,相关系数的平方均大于0.999 0。该结果验证了系统的可行性。     

Enhancement of pump conversion efficiency in preamplified L-band erbium-doped fiber amplifiers

A new configuration of L-band erbium-doped fiber amplifiers (EDFAs) is presented here. The system contains a double-pass L-band EDFA and an optical preamplifier. Different from conventional preamplified double-pass L-band EDFA systems in which only the forward ASE of the preamplifier is re-used as an auxiliary pump, the new system recycles the backward ASE of the preamplifier as well. Two kinds of main L-band EDFAs are studied, both of which include a section of un-pumped erbium-doped fiber placed in a loop reflector. An improvement of up to 110% in pump conversion efficiency is demonstrated with the proposed recycling of the backward ASE, with respect to the system without recycling.     

前置放大器在高频信号检测系统中的作用

利用约瑟夫森效应获取电磁信号的频谱信息是超导电子学的重要应用之一.我们在实验室已搭建的高频信号频谱检测系统基础上,研究了前置放大器的噪声参数对整个高频信号检测系统性能产生的影响.通过实验,我们将两个不同输入电压噪声密度的低噪声放大器应用于检测系统,并对所得的结果进行了比较.讨论了在前置放大器方面对基于约瑟夫森效应的液氮温区的小型高频信号检测系统进行改进的可能性.