摘要
对于制冷机振动幅度的测量,基于夫琅和费衍射原理研制一套振动测量装置。该装置利用样品振动与干涉条纹移动量的相关性并通过视觉成像来采集干涉条纹的移动规律,从而得到被测物体的振动信息。实验中发现在测量被测物体振动信息的过程中存在影响因素,为此对影响测量结果的因素进行分析并采用PZT(Piezoelectric Transducer)对该装置的测量准确性进行验证。结果表明,所提方法能够高精度测量得到待测样品的微小位移,测量精度可达10 nm。利用该装置可以得到采取减振措施后制冷机的振动特性,为后续优化制冷机的振动水平提供技术支撑。
Objective Gifford-McMahon(GM)cryocooler without liquid helium has gradually become the primary method to obtain a low-temperature environment,but the typical vibration displacement is about±14.6μm at the second-cold stage when the compressor is operated at 50 Hz.This vibration is still too high for some applications,such as optical interference,cryogenic microwave oscillators,X-ray phase-contrast imaging,and other precision systems that require submicron-level vibration control on the sample holder.We have developed a vibration-free cryostat using GM cryocooler years ago and measured the vibrations of the sample holder using the high-speed microscopic vision method.However,a more accurate method is needed to analyze its vibration to provide reference data for further reducing the vibration of the sample holder.Moreover,the direct contact measurement method will destroy the eigenfrequency of the system,resulting in the deviation of results from the real value.Therefore,the non-contact vibration measurement methods,such as the doppler method,triangle method,and holographic interferometry,are needed to analyze the vibration of the sample holder of the cryostat.This paper presents a novel vibration-measuring method for the measurement of the vibration amplitude of the cryocooler based on the Fraunhofer double-slit interference principle.This method not only has a high resolution,but also has the ability to measure the vibration of distant objects,and is especially suitable for cryostat vibration measurement and analysis.Methods The laser is divided into two beams by the beam splitter after collimation.Beam 1 and beam 2 are used as the reference and signal lights,respectively.First,beam 1 and beam 2 pass through the slit,respectively,to generate slit light.Then,they are reflected by mirror 1,which is fixed,and mirror 2,which is mounted on the vibration object to be measuring and pass through the slit again.Finally,the two beams focus on the focal plane by focusing the lens on generating interference fringes,acquired
作者
代飞
王凯
林伟
黎军
雷海乐
Dai Fei;Wang Kai;Lin Wei;Li Jun;Lei Haile(Research Centre of Laser Fusion,China Academy of Engineering Physics,Sichuan 621000,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2021年第24期88-96,共9页
Chinese Journal of Lasers
基金
国家自然科学基金(11804318)。
关键词
测量
惯性约束聚变
振动测量
夫琅禾费干涉
亚微米振动
measurement
inertial confinement fusion
vibration measurement
Fraunhofer double-slit interference
submicron vibration
