Development Of A Transportable Gravimeter Based On Atom Interferometry

This thesis reports on the development of our transportable atom gravimeter.The atom gravimeter is consist of the sensor system and the control cabinet system.In this thesis,the development of the platform-level gravimeter sensor system and three generations of miniaturized gravimeter sensor systems are reported in detail.The atom gravimeter sensor system is consist of several subsysmtems such as the vacumn system,the magnetic field coils system,the magnetic shielding system,the laser beam expanding system and the fluorescence detection system.Finally,by optimizing the structral design of these subsystems continuously,an atom gravimeter sensor with fine perfomance,small size and good transportability is set up.When it comes to the laser system,the platform-level laser solution has been op-timized from the initial five-lasers one to the three-lasers one by continuous optimiza-tion of the laser optics design,the laser frequency design and the laser frequency lock-ing method.After that,by developing the magnetic-enhanced MTS tecnique,designing special frequency shifing scheme and optimizing the the structure of Raman laser phase lock loop,the laser system has been simplified to the two-lasers solution,based on which,two generations of miniaturized compact laser system have been developed.This thesis also introduces the construction process of two generations of trans-portable atom gravimeter control cabinet system.By seting up the first generation of gravimeter control cabinet,the system composition of the gravimeter control cabinet and the direction for further miniaturization have been clarified.And based on these,the gravimeter control cabinet system is divided into several subsystems,and the sec-ond generation of mobile control cabinet is built up by optimizing the structure de-sign of these subsystems.The dimension of the second generation control cabinet is 680mm*560mm*720mm,which reaches the size requirement of commercial trans-portable atomic gravimeter control cabinet.In this thesis,after combining the sensor system and control cabinet system to-gether,the installation and debugging process on g value measurement are presented.The results of two comparison experiment abtained at NIM Changping campus,Beijing are also presented in this thesis.The first comparison result is abtained in the 10th Inter-national Comparison of Absolute Gravimeters(ICAG-2017)held by NIM at Changpin campus where we took the second generation gravimeter sensor system and first gen-eration control cabinet system to participate in the comparison experiment.Based on this comparison,the optimal sensitivity of our atom gravimeter is better than 30?Gal/(?).In January 2019,we tansported two sets of mobile atom gravimeters to the NIM at Chang-ping campus for comparsion experiment.The control cabinet systems of both atom gravime-ters are two second generation ones developed in 2018.One of the sensor system is of the second generation developed and the other one is of the third generation devel-oped.In this comparison experiment,the uncertainties and corrections of g value mea-surement are analyzed systemically.In both the comparion experiments,the mobile atom graviter(s)is transported from Shanghai Institute for Advanced Studies of USTC to NIM Changping campus by van transportation.After the transportation of about 1200Km,the atom gravimeter can be recovered for comparion experiment in 1.5 hours.And based on this fact,the trans-portability and stability of the atom gravimeter are well tested.