光致電壓顯微鏡之低溫恆溫器的研製

本研究討論利用聚焦光束引致電阻元件電壓變化的光致電壓顯微鏡(light-induced voltage-alteration microscope)之低溫系統設計與製作。光致電壓顯微鏡是雷射掃描顯微鏡的一種。本文我們設計並製作了雷射掃描顯微鏡的低溫恆溫器，其結構分為3大部分，分別是：杜爾瓶、視窗、線路配置。杜爾瓶主要是針對整體的恆溫效果及如何利用杜爾瓶的低溫將樣品冷却做重點設計；視窗的設計為主要的設計重點，因此部份必須呈現出無磁性的狀態，來避免影響對磁性敏感之樣品(如超導量子干涉元件)。低溫杜爾瓶與視窗等真空組件製作完成後，分別對各組件及全組裝後的系統真空側漏。另外，為了驗證光致電壓顯微鏡的概念，也利用光敏電阻作為樣品在常溫下做初步的實驗，實驗中主要是利用掃描裝置取得光致電壓反應對空間位置的圖，主要的功能是用來作為光致電壓變化靈敏區域的測定。此裝置完成後，將可以做為高溫超導薄膜微橋的臨界電流密度的非破壞檢測，並可應用於約瑟芬接面之臨界電流散佈偵測。本研究所發展的低溫系統亦可應用於超導體相變熱輻射偵測器 (superconducting transition-edge bolometer)。

關鍵字

光致電壓顯微鏡；杜爾瓶；低溫恆溫器

並列摘要

The cryostat for the light-induced voltage-alteration microscope (LIVAM) was investigated in this work. The LIVAM is a kind of the laser scanning microscope. The cryostat consisting of three major parts – the liquid-nitrogen Dewar flask, the view port, and the wiring for electrical-signal readouts. The function of the Dewar flask is to cool the samples to about 80 to 90. The view port consists of a acrylic and a quartz window. A Teflon bellow was used for adjusting the distance between the window and the sample. All the materials of the view port are non-magnetic. This allows the magnetic-sensitive samples to be measured. When the cryostat was finished, we performed leakage test to check the vacuum tightness of the system. Besides, we prove the concept of LIVAM by scanning the focused laser beam over a thermistor to obtain a two-dimensional image of voltage response. From the image, one can determine the photo-sensitive region of a the thermistor. The developed cryogenic system is useful in detecting the critical current density of superconducting films and Josephson junctions. In addition, it could be used as the cryostat for the superconducting transition-edge bolometer.

並列關鍵字

light-induced voltage-alteration microscope ； dewar ； cryostat

參考文獻

[7] 李冠勳，差動式渦電流探頭於缺陷偵測之最佳激發頻率研究，國立台北科技大學碩士學位論文，2005年。

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光致電壓顯微鏡之低溫恆溫器的研製

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