Speaker
Description
Conventional high-resolution techniques for $\beta$-decay spectroscopy utilize high-purity germanium detectors to measure individual $\gamma$ rays emitted after $\beta$ decay. However, these measurements are affected by the Pandemonium systematic error [1], resulting in many high-energy $\gamma$ rays and a significant portion of the $\beta$ strength being missed. The Total Absorption $\gamma$-ray Spectroscopy (TAGS) technique effectively addresses this issue [2, 3]. It relies on detecting the full energy of $\gamma$ cascades following the decay, achieved through the use of large, high-efficiency scintillation crystals acting as calorimeters. This technique allows for a Pandemonium-free determination of the $\beta$ strength, a fundamental quantity that depends on the underlying nuclear structure, thus the ideal tool for constraining theoretical models.
The TAGS technique has been successfully utilized in $\beta$-decay studies for many years, yielding important results relevant to nuclear structure, nuclear astrophysics, and applications in reactor and neutrino physics (see Ref. [3] for a recent review). In my talk, I will highlight some selected achievements. I will then introduce Experiment E891_23 [4], which has been granted beam time at the GANIL laboratory in France. The experiment aims to measure the $\beta$-decay properties of several proton-rich nuclei in the Cr-Zn region, of significant interest for both nuclear structure [5, 6] and nuclear astrophysics. This experiment will be performed with a new-concept hybrid spectrometer, STARS, currently under development within the (NA)$^{2}$STARS project [7]. STARS will be the world’s first device to combine the large $\gamma$ efficiency characteristic of TAGS calorimeters with the superior energy resolution and timing of LaBr$_{3}$(Ce) crystals. This unique combination will enable unprecedented studies further away from nuclear stability.
[1] J.C. Hardy et al., Phys. Lett. B 71, 307 (1977).
[2] B. Rubio et al., J. Phys. G Nucl. Part. Phys. 31, S1477 (2005).
[3] A. Algora et al., Eur. Phys. J. A 57, 85 (2021).
[4] Experiment E891_23: “Total Absorption Spectroscopy for Nuclear Structure and Nuclear Astrophysics” (spokespersons: M. Fallot, S.E.A. Orrigo, A.M. Sánchez Benítez), approved by the GANIL Program Advisory Committee, Nov. 2023.
[5] S.E.A. Orrigo et al., Phys. Rev. Lett. 112, 222501 (2014).
[6] S.E.A. Orrigo et al., Phys. Rev. C 93, 044336 (2016).
[7] Project (NA)$^{2}$STARS: “Neutrinos, Applications and Nuclear Astrophysics with a Segmented Total Absorption with a higher Resolution Spectrometer” (spokesperson: M. Fallot), endorsed by the GANIL Scientific Council, Jan. 2023.
| session | I. Nuclear Structure and Reactions |
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