Pulsed-wire Method of Field Measurement on Short Elliptically Polarlized Undulator

With two sets of photo couplers, scientists already have applied pulsed-wire method (PWM) to measure the magnetic field along two mutually perpendicular directions. The authors believe that two-dimensional pulsed-wire method is useful for the test of elliptically polarizing undulator (EPU). We tried to use this method to observe the first integral and second integral fields of a short EPU in real time during the polarization tuning. More care is needed than the application of PWM on the planner undulators. The phase difference, the relative field strength along two directions as well as the precise center-line can be achieved.