Result of Powering and Field Measurements on the GaToroid Demonstrator

GaToroid is a novel idea of a steady-state, toroidal magnet that directs multiple charged particle beams for hadron or electron therapy without rotating parts or magnet ramping. GaToroid has the potential of conformal radiotherapy with a configuration that can be simpler and lighter than conventional rotating gantries, also offering FLASH capability well beyond what is presently possible. A crucial feature of the magnet is the field profile, which is optimized to maximize acceptance (large field area) and beam transmission (good field homogeneity). We have built and tested a 1:3 scale Nb-Ti demonstrator of the proton GaToroid to verify performance, field profile and quench protection. Here we describe the specific features of the demonstrator cable, coil and magnet, and report the main test results. The magnet reached critical current with no training, the field profile is within 1% of the expected values, and quench detection and protection are well understood, thus proving that this magnet technology is ripe for a full-size system demonstration.