Speaker
Description
The Advanced Cryogenic Gas Stopper (ACGS) [1] is the primary device used at the Facility for Rare Isotope Beams (FRIB) to convert fast beams of exotic nuclei into low-energy beams, which are delivered to the stopped beam experimental area or to the re-accelerator facility (ReA). As FRIB continues a phased ramp-up of primary beam power, ACGS must efficiently stop and extract increasingly intense beams while managing the associated charge creation from gas ionization, which is at times further amplified by intense satellite fragments accompanying the exotic ions of interest. FRIB beam production has also recently expanded to include fission products from a $^{238}$U primary beam, which exhibit differing beam properties and therefore new beam stopping requirements compared to the fragmentation mechanism primarily used thus far. In addition to matching the unique profile of emittance, dispersion, rate, purity, and mass for each incoming beam, ACGS must also effectively meet the differing rate, purity, and chemical form requirements for each experimental end station.
This presentation will detail the recent operation and performance of ACGS, highlighting the new beams and new operational regimes accompanying the ramp-up of rare isotope beam production at FRIB. Total efficiency measurements will be presented along with discussion of the individual contributing components and dependence on various operating parameters. Methods used to manipulate low-energy beam properties to meet experimental requirements, such as charge state manipulations with buffer gas purity and reduction of molecular sidebands via collision-induced dissociation, will also be presented.
[1] K.R. Lund et al., Online tests of the Advanced Cryogenic Gas Stopper at NSCL, Nucl. Instrum. Methods Phys. Res. B 463 (2020) 378
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the Facility for Rare Isotope Beams (FRIB), which is a DOE Office of Science User Facility, operated by Michigan State University, under Award Number DE-SC0000661
| Email address | izzo@frib.msu.edu |
|---|---|
| Classification | Ion guide, gas catcher, and beam manipulation techniques |
