The Facility for Rare Isotope Beams signifies a major advancement in rare isotope beams for research. Delivering heavy and exotic rare isotope beams is accomplished with the Advanced Rare Isotope Separator (ARIS), which creates, purifies and transports radioactive beams. These secondary beams can range from hydrogen to uranium. Every RIB is carefully planned, produced and characterized by ARIS’s system of diagnostics, detectors and data acquisition (DAQ). ARIS detectors can measure the time of flight, energy loss, charge, gamma-rays and position of the species in the beam, allowing the identity, rate, purity, energy and emittance of each rare isotope to be accurately quantified. The needs of each experiment drive the requirement for tuning, to achieve the desired RIB properties for diverse experiments. In this presentation, the current ARIS system of scintillators, PPACs (parallel plate avalanche counters), silicon and gamma-ray detectors, and associated DAQ will be discussed. Furthermore, the ARIS detector system will undergo upgrades to support the main LINAC upgrades from the current 20kW, and these upcoming challenges and changes to detectors and DAQ will be included as well.

The Facility for Rare Isotope Beams (FRIB), operating at Michigan State University since 2022, produces a variety of nuclear species via fragmentation or fission. Heavy ions are accelerated by the FRIB LINAC to energies of >170 MeV/u which impinge on mm-thick graphite targets to make the RIs in-flight. The resulting cocktail of ions are separated and purified with the Advanced Rare Isotope Separator (ARIS). Magnetic separation of isotopes with the same A/Z ratio is performed with an achromatic energy degrader or wedge. As the first stage of ARIS involves a momentum compression of k=3, the pre-separator wedge geometric cross section is more complex than a simple isosceles triangle, having a parabolic shape to reduce aberrations. Wedge inhomogeneities from imperfect machining or within the material itself (e.g., bubbles, density variations) can adversely affect the beam's phase space, resulting in a larger beam spot size and lower transmission. Here we report a comparison of different wedge materials using standard beam diagnostics from viewers and position-sensitive detectors. Particular attention is paid to the calibration procedure for parallel plate avalanche counters (PPACs).

The Facility for Rare Isotope Beams (FRIB) provides rare-isotope beams for user experiments in nuclear physics, nuclear astrophysics, fundamental symmetries, etc. A superconducting driver-linac accelerates heavy-ion beams onto the production target, and the Advanced Rare Isotope Separator (ARIS) collects and purifies the rare isotope fragments of interest. Subsequently, the transfer hall beamlines deliver isotopes to user setups at experiment stations. The isotope beam condition from ARIS strongly depends on the fragment of interest. Therefore, the beamline settings are optimized for each experiment based on various users’ requirements on the fly. Two new beamlines in the transfer hall were commissioned in 2025, bringing the total number of available end stations to five. Since the first user experiments in 2022, ongoing beam tests and operations have continued to improve operational efficiency and user satisfaction. Results and findings of beam tuning obtained from the commissioning and recent operations will be reported.