環境および振動に起因する磁気ノイズの予測.低減技術の開発と 磁気シールドルーム，建築構造物の三次元磁界解析技術の確立

摘要

Magnetically shielded rooms (MSRs) and active shielding for electron-beam lithography systemsshould be designed taking into account the magneticdisturbances due to dc-electric railcars and movingautomobiles. The MSRs for biomagneticmeasurements should also be designed taking intoaccount of the S / N ratio of the biomagnetic signalto the environmental magnetic noise generatedmainly by the dc-electric railcars and movingautomobiles at installed locations. First, thecharacteristics of their fluctuations in magnetic noisedue to dc-electric railcars and a method ofpredicting their amplitude were investigated bymeasuring these. Next, the characteristics offluctuations in magnetic field from moving automobilesand a method of predictiing their amplitude werealso investigated by measuring them. However, thesensitivity of the biomagnetic measurements waslimited by residual magnetic noises in the MSRs,which are caused by mechanical microtremors as wellas environmental magnetic noise generated byelectric trains and, automobiles at low frequencies.Third, an Active Microtremor Isolation (ACMI) systemwas installed in the basements underneath theMSRs to reduce the noise due to microtremors andwhat effect it had on reducing magnetic noise wasestimated with a SQUID magnetometer.