Work

Beam diagnostics in ARIS to investigate wedge defect at FRIB

Year: 2025
Type: conference-paper
Abstract: 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).
Source: JACOW
Authors: Kahl,Daid, Dombos,Alexander, Sherrill,Bradley, Jacobson,Daniel, Wakai,Eiichi, Kwan,Elaine, Choi,Evan, Fukushima,Kei, Privatte,Luke, Smith,Mallory, Hausmann,Marc, Cortesi,Marco, Steiner,Mathias, Portillo,Mauricio, Tarasov,Oleg, Manwiller,Peter, Di Carlo,Salvatore, Rodriguez Esparza,Sergio, Rao,Xing
Language: English
Open Access status: hybrid
OpenAlex ID: W7090963482
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