New Commissioning Results of the MIST-1 Multicusp Ion Source

Abstract

Abstract For the sterile neutrino experiment IsoDAR (Isotope Decay-At-Rest), we have developed a compact particle accelerator system delivering a 10 mA, continuous wave (cw) proton beam at 60 MeV to a neutrino production target. The accelerator comprises a compact isochronous cyclotron, an RFQ embedded in the cyclotron yoke, and an ion source. To reduce space charge effects during injection and acceleration, we are accelerating H+ 2 instead of protons. To produce the needed cw H+ 2 beam current of 10 mA (nominal) at the required purity and quality, we have built a new filament driven, multicusp ion source (MIST-1). Here we report commissioning results for long-time running at reduced power, demonstrating the feasibility of the design. Highlights include an H+ 2 beam current density of ≈ 10 mA/cm2, ≈ 80% H+ 2 fraction, and extrapolated emittances of 0.05 π-mm-mrad (RMS, normalized) after extraction. We also present high fidelity simulations that are in good qualitative and quantitative agreement with emittance measurements in our test beam line.