Precise measurements of peak fields of pulsed quadrupole magnets

Abstract

A peak-to-dc comparison method using search coil techniques and an oscilloscope was developed for measuring peak fields of pulsed magnets precisely. The emf induced in a search coil is integrated and the peak voltage of the integrated emf is measured by comparison with a dc reference voltage. For a pulse width as short as 1 ms, a relative measuring accuracy within 0.01% was obtained. This method was used to determine some peak field characters of drift tube quadrupole magnets for a 20 MeV proton linac. In the appendix is described the performance of another method, the reference pulse method, where the integrated emf is compared with a reference pulse. For the precise measurement of the peak field, automatic detection of the peak field timing is necessary in order to determine the comparison point.