[S-EM34] 地磁気・古地磁気・岩石磁気

[SEM34-13] SQUID顕微鏡のS/N向上に向けて

*小田 啓邦¹、佐藤 雅彦¹、野口 敦史^3,1、高橋 浩規^4,1、河合 淳²、宮本 政和² (1.産業技術総合研究所地質情報研究部門、2.金沢工業大学、3.高知大学、4.茨城大学)

キーワード：走査型SQUID顕微鏡、ノイズ、磁気シールド、S/N比、校正

We have been developing scanning SQUID (superconducting quantum interference device) microscope for geological samples. In this presentation, we will demonstrate improvements in our scanning SQUID microscope system. We introduce external magnetic shielding by thin shield film outside of a double-layered PC permalloy magnetic shield box surrounding scanning SQUID microscope. We also develop internal magnetic shield just outside of scanning SQUID microscope with five layered shield film for AC and DC shielding. With this set-up, we also introduce a reference SQUID sensor inside liquid helium dewar in order to compensate noise originated from environmental magnetic field. Resulting signal-to-noise ratio is going to be analyzed and reported. In addition, we show a calibration procedure for our scanning SQUID microscope in terms of its sensitivity and deviation from vertical axis.