| 研究実績の概要 |
The new project for an in-MRTOF deflection system has been completed with great success and applied to different MRTOF-MS systems. In FY2020, before the installation, the required voltage pulse sequence has been developed [M. Rosenbusch et al., NIM A 1047, 167824 (2022)]). Result: Discovery of a low N=34 two-neutron shell gap in Ti and V isotopes [S. Iimura, M. Rosenbusch et al., PRL 130, 012501 (2023)].
The construction took place FY2020/2021. Tests were performed using molecules ionized in helium. The molecules have been forwarded to the MRTOF-MS. Using the developed pulse sequence, a single mass unit was transmitted to the TOF detector while all other have been removed. New programming allowed for multiple mass units (e.g. A=74, A=75, and A=76) simultaneously while excluding all others.
In FY2021/FY2022, this new system was applied for experiment RIBF199 and RIBF202 (see RIKEN RIBF). Result: Masses of 73Ni and 74Ni were measured at the same time, and also 74Ni and 75Ni (publication FY2023).
In FY2021 two other deflector systems have been installed in MRTOF-MS systems. In FY2021 the in-MRTOF deflector at the GARIS-II enabled taking data on the superheavy isotopes 257Db [RIKEN Accel. Prog. Rep. 55, 6 (2022)] and also 258Db [RIKEN Accel. Prog. Rep. 55, 7 (2022)].
During FY2022, the in-MRTOF deflector allowed to solve the problem of the unknown charge states for different chemical elements. A fission source (10kBq, Am) produced a large variety of radioisotopes. Ions have been selected and the dominant charge state could be revealed for upcoming accelerator experiments.
|
