Noninvasive beam-size measurements for linear induction accelerators

Abstract

Diamagnetic loops (DML) can be used as a noninvasive method for the measurement of beam size in electron beam accelerators that use solenoidal magnetic transport. The loop fundamentally measures the magnetic flux excluded by a diamagnetic object. A comprehensive theory relates the rms beam radius to the excluded flux measured by the DML. We have built and calibrated a DML apparatus. Recently, this DML has been used to measure the size of the electron beam near the final focus of a flash-radiography linear induction accelerator. The results are in agreement with predictions from transport code simulations. In this article, we review and summarize the construction, calibration, and electron-beam testing of this DML.