Beam Commissioning of the 750 MHz Proton RFQ for the LIGHT Prototype

ADAM (Application of Detectors and Accelerators to Medicine), a CERN spin-off company, is developing the Linac for Image Guided Hadron Therapy, LIGHT, which will accelerate proton beams up to 230 MeV. The design of the linac will allow fast intensity and energy modulation for pencil-beam scanning during cancer treatment. The linac consists of a 40 keV Proton Injector; a 750 MHz Radio Frequency Quadrupole (RFQ) accelerating the proton beam up to 5 MeV; a 3 GHz Side Coupled Drift Tube Linac (SCDTL) up to 37.5 MeV; and a 3 GHz Cell Coupled Linac (CCL) section up to 230 MeV. A prototype of LIGHT is being commissioned progressively with the installation of the accelerating structures at a CERN site. The beam commissioning of the RFQ, which was designed and built by CERN, was completed in 2017 using a movable beam diagnostic test bench with various instruments. This paper reports on the RFQ commissioning strategy and the results of the beam measurements.