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A GRB polarimeter was launched by H-IIA on 21 May in 2010 at JAXA Tanegashima Space Center. A GRB polarization is the best key to understand mechanism of GRB prompt emissions and also to understand the geometry of magnetic fields. The standard GRB fireball models predict the synchrotron radiation of them, thus a high degree of polarization is expected, if the magnetic field-lines are coaligned. Previously, a few of the GRB polarization detections were reported. Although they used the Compton scattering method, but their measurements were non-coincidence mode. This made their reports were somewhat unclear. This time, our detector works fully in the coincidence mode to avoid the confusion. On 21 June, GAP is switched on and the first GRB was detected on 7 July but not yet well calibrated. [ABSTRACT FROM AUTHOR]

We used an YBCO (YBa[sub 2]Cu[sub 3]O[sub 7]) rf SQUID planar gradiometer and an excitation method to detect small metal. In our experiments, an excitation field with higher frequency of 12 kHz was used to increase signal-to-noise ratio. By using a spectrum subtraction method, we could successfully detect a tin solder particle as small as about 2 mm and 30 mg in the position of about 5 cm underneath the dewar. We could also discriminate different types of metals by their characteristic phase signal. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]