Mass measurements of exotic N=Z nuclei (up to 100Sn) and the vicinity for nuclear physics and nuclear astrophysics studies (MASSPASS)

Main funder

Funder's project number: 354589

Funds granted by main funder (€)

Funding program

Project timetable

Project start date: 01/09/2023

Project end date: 31/08/2027

Summary

The evolution of nuclear shell structure can be investigated by mass measurements of isotopic and isotonic chains. Masses also play an important role nuclear astrophysics. The region of the heavy N = Z (A=78-100) nuclei and the vicinity near 100Sn on the chart of nuclides to be studied, has sparked interests for both nuclear astrophysics and nuclear structure for many years. Nuclear mass data along the heavy neutron-deficient N = Z line and its neighbors are crucial for the investigation of the rp- (rapid-proton capture) and the νp-(rapid-neutrino capture) processes. In addition, access to nuclei on (or more proton-rich than) the N = Z line is needed to solve key challenges related to many open questions in nuclear structure as well. The masses of neutron-deficient exotic nuclei in the mass region near N=Z line will be measured with the Penning trap mass spectrometer JYFLTRAP of the Ion Guide Isotope Separator On-Line (IGISOL) facility of JYFL-ACCLAB in the University of Jyväskylä/Finland and the Radioactive Isotope Beam Factory (RIBF) facility at RIKEN/Japan. IGISOL is by far the place to have achieved the highest resolution to do these measurements for the heavy N=Z area nuclei with the JYFL setup. The utilization of the TOF-ICR and the PI-ICR methods with a precision ~ 1 keV, while the nuclei with half-lives less than 100 ms down to few ms, the masses will be measured with the MR-TOF MS with a precision of few tens of keV. At RIBF, Bρ-TOF method simultaneously in conjunction with the Isochronous Mass Spectrometry (IMS) method with the Rare-RI Ring. The IMS method will be employed to address the masses of nuclei with half-lives ranging from 100 us to 1 ms with a precision of ~ 100 keV and the Bρ-TOF method will be used to measure the extremely short-lived nuclei with half-lives less than 1us. The masses of more than 20 nuclei will be measured at the IGISOL and RIBF Facilities. The results will not only provide essential data for modeling rp-process and the νp-process in astrophysics, but also help reveal new insights into several open questions for nuclear structures such as: origin of the Wigner energy; super allowed GT decay of 100Sn; the location of the proton drip-line; deformation and the evolution of shell-closures (N=Z~40); test of mass models; isospin symmetry breaking; puzzle of two protons and one proton decay of 94Ag high level long isomer state; and the test of the CVC hypothesis. Any of breaking through and will be published in Journal of high impact.

Principal Investigator

Other persons related to this project (JYU)

Primary responsible unit

Follow-up groups

Profiling area: Accelerator and Subatomic Physics (University of Jyväskylä JYU); School of Resource Wisdom (University of Jyväskylä JYU) JYU.Wisdom; School of Wellbeing (University of Jyväskylä JYU) JYU.Well

Free keywords

N=Z nuclei, Mass measurement, Penning trap, MR-TOF, Storage Ring, Nuclear physics, Nuclear astrophysics

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