The Facility for Rare Isotope Beams (FRIB) being constructed at Michigan State University [J. Wei et al., The FRIB superconducting linac-status and plans, LINAC'16, Lansing, MI, p. 1, http://accelconf .web.cern.ch/AccelConf/linac2016/papers/mo1a01.pdf] is based on a cw superconducting linear accelerator which is designed to deliver unprecedented 400 kW heavy ion beam power to the fragmentation target. The installation of the accelerator equipment is approaching completion and multistage beam commissioning activities started in the summer of 2017 with expected completion in 2021. A roomtemperature test electron cyclotron resonance ion source, ARTEMIS, provided argon and krypton beams for the commissioning of the low energy beam transport, a radio frequency quadrupole (RFQ), the medium energy beam transport (MEBT) and the first three accelerating cryomodules. The commissioning of the first linac segment (LS1), composed of 15 cryomodules, is planned in the spring of 2019. This paper describes the first results of experimental beam dynamics studies in the LEBT, RFQ, MEBT and the first three cryomodules with comparison to the numerical simulations.

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

With about 1000-h of relativistic high-energy ion beams provided by Heavy Ion Medical Accelerator in Chiba, about 70 users are performing various biology experiments every year. A rich variety of ion species from hydrogen to xenon ions with a dose rate of several Gy/min is available. Carbon, iron, silicon, helium, neon, argon, hydrogen, and oxygen ions were utilized between 2012 and 2014. Presently, three electron cyclotron resonance ion sources (ECRISs) and one Penning ion source are available. Especially, the two frequency heating techniques have improved the performance of an 18 GHz ECRIS. The results have satisfied most requirements for life-science studies. In addition, this improved performance has realized a feasible solution for similar biology experiments with a hospital-specified accelerator complex.

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Linac segment 1 (LS1) of the FRIB driver linac is composed of 15 cryomodules, consisting of 104 superconducting (SC) resonators and 39 SC solenoids. Four ion beam species (Ne, Ar, Kr, and Xe) were successfully accelerated up to 20.3 MeV=u in LS1 and transported to the designated beam dumps located in folding segment 1 (FS1). 100% beam transmission was measured through all cryomodules and the warm section of LS1. High-power equivalent beams were delivered to the beam dump in two modes: pulsed and continuous wave (cw). In the pulsed mode, the peak intensity of the argon beam was 14.8 pμA at 3% duty factor, which constitutes 30% of the FRIB design intensity for this particular ion beam. A cw argon beam was accelerated, demonstrating that the FRIB linac in its current configuration is the highest-energy cw superconducting hadron linac in the world. This paper presents a detailed study of beam dynamics in LS1 prior to and after charge stripping with a carbon foil.