1-1hit |
Mizushi MATSUDA Tsutomu MATSUURA Koichi KATO Hiroshi OYAMA Amane HAYASHI Satoru HIRANO Shinya KURIKI
We have fabricated and characterized two types of high-Tc planar SQUID gradiometers having different line width of pickup loops. The device worked in flux-locked loop (FLL) operation even in laboratory environment without any shielding. A magnetic field gradient resolution of a parallel-type device in a lightly shielded room was about 0.5 pT/cmHz1/2 at 1 kHz and 2 pT/cmHz1/2 at 1 Hz. The device was possible to record magnetocardiograms in a shielded room. QRS-complex peaks of about 10 pT PP/4mm are clearly observed. For a mesh-type device, the increase of low frequency noise in the open laboratory environment was less than that for a parallel-type.