研究生: |
吳峻東 |
---|---|
論文名稱: |
光激發原子磁量儀控制電路及交流磁化率量測之研究 |
指導教授: |
楊鴻昌
Yang, Hong-Chang 洪姮娥 Horng, Herng-Er |
學位類別: |
碩士 Master |
系所名稱: |
光電工程研究所 Graduate Institute of Electro-Optical Engineering |
論文出版年: | 2012 |
畢業學年度: | 100 |
語文別: | 中文 |
論文頁數: | 40 |
中文關鍵詞: | 原子磁量儀 |
論文種類: | 學術論文 |
相關次數: | 點閱:126 下載:0 |
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摘要
目前已成功獲得磁共振訊號、結合回饋控制電路測量外加磁場。另外製作一組線圈量測磁流體的交流磁化率,再將此線圈耦合給原子磁量儀做量測。
我們以795 nm圓偏振光入射銣元素圓柱形玻璃容器,其放置於一磁屏蔽環境,在此環境內以Helmholtz線圈產生均勻磁場,磁場方向與光前進方向相夾45度角,另外我們在與靜磁場垂直之方向,提供一射頻磁場使其產生共振效應,以光偵測器探測銣金屬蒸氣之磁共振效應,並以鎖相放大器測量與射頻磁場同相位(in-phase)及九十度相位差(quadrature)電壓訊號對頻率的關係圖。
接著我們製作回饋控制電路使得系統能測量外加磁場的頻率響應。鎖相放大器擷取一直流電壓輸出,訊號經積分器與加法器調整後,作為電壓控制振盪器之輸入,以產生特定頻率的交流訊號,交流訊號分別回饋給射頻磁場線圈產生新的共振頻率和鎖相放大器作為參考訊號。當系統有一微小磁場變動時,立即將訊號回饋給系統以達到新的共振穩態,透過獲取鎖相放大器電壓改變,得知瞬間磁場相對於初始磁場變動的大小。5Hz以下能準確測量,結果取決於系統的反應時間和外加磁場大小需在Pip線性關係內。
交流磁化率方面,我們製作一組量測線圈,包含激發線圈、擷取線圈和補償線圈,經過不斷反覆調整補償線圈的振幅和相位後,使得背景電壓值小於待測磁流體的訊號變化量,此時再將磁流體置放在量測線圈中心處並結合原子磁量儀量測其訊號變化量。
關鍵字:原子磁量儀
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