| Summary: | 碩士 === 國立中央大學 === 物理學系 === 101 === To demonstrate the electromagnetically induced transparency in gamma rays region at the single photon level via the level crossing and level anti-crossing technique. The difficulty of obtaining pure FeCO3(siderite) single crystal is the bottleneck in the experiment. Impurity in the crystal will break structure of crystal, making level crossing phenomenon unable to achieve. For the sake of further study of nuclear level crossing and nuclear level anti-crossing, we have to adjust the concentration of CaCO3 and MgCO3 in siderite crystal for controlling the direction between magnetic hyperfine field and c-axis and EFG in the crystal. Hence the necessity for developing the method of FeCO3 crystal growth and crystal characterization is obvious.
The main achievement of this thesis is develop a fully developed Mössbauer spectrometer and a platform for crystal characterization. By a series of improvement on hardware and software, we can push up the signal to noise ratio of Mössbauer spectrum to the theoretical limit. And setup a cryostat system for future experiment. The source code of signal to noise evaluation program and data processing program will attach as an appendix. Finally, the FeCO3 thin film were used for testing the performance of spectrometer, then characterize the sample by experimental data and the theoretical explanation.
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