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Description
For the N=50 isotones $^{90}$Zr and $^{92}$Mo, additional isovector spin-flip M1 (IVSM1) strength could be expected for $^{92}$Mo in comparison to $^{90}$Zr because of the two additional protons in the proton g$_{9/2}$ orbital above the closed pf shell. In addition, the IVSM1 resonance is closely related to Gamow-Teller strengths and can serve to constrain the calculation of electron-capture rates in core-collapse supernova scenarios [1]. Using the newly available hybrid array of HPGe Clover and LaBr$_3$ detectors at the High-Intensity γ-ray source (HIγS), we probed the dipole response of both isotopes in an integral-spectroscopy approach below neutron separation thresholds. The E1 and M1 strengths will be determined up to about 9 MeV by measuring the asymmetries resulting from the excitation of the target nuclei by the fully
polarized γ-ray beam. The experimental method and first results will be discussed.
This work has been supported by DFG Project No.279384907-SFB 1245 and the U.S. DOE Grant No. DE-FG02-97ER41041 and DE-FG02-97ER41033.
[1] K. Langanke et al., Rep. Prog. Phys. 066301 (2021).
