建構一振動樣品磁力計及其應用之研究

我們建構一套以直流馬達驅動的振動樣品磁力計(Vibarting Sample Magnetometer)，系統的正弦運動曲線振幅為2 mm (上下 1 mm)，可控制頻率範圍為 0 ~ 20 Hz。樣品管使用鐵氟龍材質製成以期能避免因材料本身產生的信號干擾到量測結果。樣品支撐桿則以45公分長之碳纖維管製成，因此材料質輕又強固。樣品管則直接接到支撐桿的尾端。系統的設計思考為將系統設定為通用機種，使用者可視樣品種類來決定使用何種磁場源來進行量測。因此，將系統振動源構成機架、偵測線圈組合架與磁場源三者設計成獨立機件，使用者可視需要簡易更換磁場源或偵測線圈組合。系統功能係以實驗室現有之Quantum Design超導量子干涉元件(Supercoducting Quantum Interference Device) 磁力計量測軟磁材料(矽鋼)與已知磁化強度之磁流體的數據作為比較依據，兩者數據比較證明我們建構之磁力計具有一定之準確度。對磁流體的量測可達1.35 * 10-3 emu. 最後我們選擇一永久磁鐵的外加磁場進行磁流體磁減量免疫量測，藉由磁減量免疫量測結果，我們發現系統之背景值(雜訊)在未加屏蔽的情況下約在數百奈伏(nV)之間，與磁鬆弛(magnetic relaxation)、殘磁量(magnetic remanence)、混頻交流磁導率(frequency mixing ac magnetic susceptibility)及單頻交流磁導率(ac magnetic susceptibility)等等不同檢測方式所量測到的磁減量免疫量測信號變化約在數十奈伏(nV)之間尚有一個數量級的差距，而要達到量測此一數量級的訊號變化，系統之背景值(雜訊)至少要再降低兩個數量級。因此，欲使系統能應用在生醫磁減量量測的首要任務就是建構一能隔絕DC磁場與低頻雜訊的屏蔽環境，如此才有可能。

關鍵字

振動樣品磁力計；超導量子干涉元件；磁性減量免疫量測

並列摘要

We constructed a simple vibrating sample magnetometer with DC motor drive system to control the sinusoidal motion frequency from 0 Hz to 20Hz with 2 mm (+/- 1 mm) amplitude. The sample holder was made of PE in order to reduce the interference from signal caused by metal materials, the sample rod was made of fiber-carbon tube with 45 cm long and was screwed on the end where the sample holder is attached. Depends on the sample type, the user can decide which component can be used to measure their sample. Therefore, the vibrating mechanism, the detecting coils set and the magnetic field source were designed into three independence components. Iron and magnetic fluid samples are studied by using this system and the data compared with data collected with Quantum Design’s supercoducting quantum interference device magnetometer to show the performance of the VSM，the result show the performance is not far away from the commercial VSM and the measurement of MF can reach 1.35 * 10-3 emu. Finally, we used this simple VSM for the application to biological immunoassay. In the application the biding reaction between an antigen and its antibody is magnetically detected by the VSM. Compare with the result, it shows background noise is in the range of few hundred of nano-V, it is higher than the magnetic reduction measurement using by other methods which are mostly in the tens of nano-V range. In order to make VSM can be used with SQUID for magnetic reduction measurement in the biological immunoassay in the future, A DC magnet and low-frequency noise shielding is necessary to develop at the first next step.

並列關鍵字

Vibrating sample magnetometer ； SQUID ； ImmunoMagnetic Reduction

參考文獻

[4] S. Foner, digital Encyclopedia of Applied Physics, “MEASUREMENT OF MAGNETIC PROPERTIES AND QUANTITIES”, WILEY-VCH Verlag GmbH & Co KGaA,

[5] S. Foner, “Versatile and Sensitive Vibrating-Sample Magnetometer”, Rev. Sci. lnstrum. vol. 30, no. 7, 1959, pp. 548-557.

[6] S. Foner, “Further improvements in vibrating sample magnetometer sentivity”, Rev. Sci. lnstrum., vol. 46, no. 10, October 1975. pp. 1425-1426.

[7] E. O. Samwel, T. Bolhuis and J. C. Lodder, “An alternative approach to vector vibrating sample magnetometer detection coil setup”, Rev. Sci. Instrum. vol.69, no. 9, 1998. pp. 3204-3209.

[8] J.P.C. Bernards, “Design of a detection coil system for a biaxial vibrating sample magnetometer and some applications”, Rev. Sci. Instrum. vol. 64, no.7, 1993 , pp. 1918-1930.

國際替代計量

建構一振動樣品磁力計及其應用之研究

未授權

主題瀏覽