Installation and Testing of a Diamagnetic-Loop-Based Beam Radius Monitor (BRM) on the DARHT-I Linear Induction Accelerator

Diamagnetic loops (DML) provide a non-invasive method for 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 the DARHT-I flash-radiography accelerator. Results agree with beam transport code predictions. In this article, we review and summarize the construction, calibration, and electron-beam testing of this DML.