Abstract: An undulator is adapted to a synchrotron storage ring or free electron lasers (FEL), especially to an undulator capable of switching polarization mode rapidly. In comparison with the EPU (elliptically polarized undulator) of APPLE II (Advanced Planar Polarized Light Emitter II) which conceived by Dr. S. Sasaki, the provided undulator does not use mechanical transmission mechanisms to drive the four magnetic pole arrays composed of permanent magnets. Hence, the polarization mode can be switched rapidly. Moreover, a polarization method of electron beam is also provided.

Abstract: An undulator is adapted to a synchrotron storage ring or free electron lasers (FEL), especially to an undulator capable of switching polarization mode rapidly. In comparison with the EPU (elliptically polarized undulator) of APPLE II (Advanced Planar Polarized Light Emitter II) which conceived by Dr. S. Sasaki, the provided undulator does not use mechanical transmission mechanisms to drive the four magnetic pole arrays composed of permanent magnets. Hence, the polarization mode can be switched rapidly. Moreover, a polarization method of electron beam is also provided.

Abstract: A passive alternating current sensor for sensing a current-carrying conductor is disclosed. The passive alternating current sensor includes a substrate, a magnetic body, at least one coil and a first measuring circuit. The substrate has a flexible structure layer. The magnetic body is disposed correspondingly to the current-carrying conductor and located at one side of the substrate. The coil is disposed on the substrate and correspondingly winds around the magnetic body. The first measuring circuit is connected with the coil. When the magnetic body is subjected to the magnetic field generated by the current-carrying conductor and enabled a relative motion with the coil, the coil produces an induced electromotive force. The first measuring circuit measures the induced electromotive force and accordingly outputs a first induction signal.

Abstract: A passive alternating current sensor for sensing a current-carrying conductor is disclosed. The passive alternating current sensor includes a substrate, a magnetic body, at least one coil and a first measuring circuit. The substrate has a flexible structure layer. The magnetic body is disposed correspondingly to the current-carrying conductor and located at one side of the substrate. The coil is disposed on the substrate and correspondingly winds around the magnetic body. The first measuring circuit is connected with the coil. When the magnetic body is subjected to the magnetic field generated by the current-carrying conductor and enabled a relative motion with the coil, the coil produces an induced electromotive force. The first measuring circuit measures the induced electromotive force and accordingly outputs a first induction signal.