Speaker
Description
A new cryogenic ion catcher filled with helium gas has been commissioned at the ZeroDegree spectrometer following BigRIPS at RIKEN/RIBF for the thermalization of high-energy RI beams from the BigRIPS beamline, as a part of the SLOWRI facility. The ion catcher is combined with a multi-reflection time-of-flight mass spectrograph and both are located downstream of the ZeroDegree spectrometer. This setup had its first on-line commissioning run in December 2020, where we measured more than 70 nuclear masses including 3 new masses [1, 2].
The ion catcher consists of a reentrant cryogenic catcher gas cell and an outer vacuum chamber. The catcher gas cell has a two-stage RF carpet configuration [3]. In off-line tests, the ion transport was first investigated using surface ionization ion sources, followed by Ar$^+$ and Kr$^+$ ions produced by $\alpha$-particle emission in the helium gas. Recently, we have started ion transport tests using the fission products from a $^{248}$Cm fission source. We are investigating the ion transport efficiency and charge state distributions for the fission products of various elements.
In this talk, I will give an overview of the development of the ion catcher, possible plans for future upgrades, and prospects.
[1] S. Iimura et al., Phys. Rev. Lett. 130, 012501 (2023).
[2] M. Rosenbusch et al., Nucl. Instrum. Meth. A 1047, 167824 (2023).
[3] A. Takamine et al., RIKEN Accel. Prog. Rep. 52, 139 (2019).
