Mon·Jan 24, 2022Monday·January 24, 2022

1. 01*

   Updated evaluation of potential ultra-low Q value $\beta$-decay candidates

   Dakota K. Keblbeck · Ramesh Bhandari · Nadeesha D. Gamage · Madhawa Horana Gamage · Matthew Redshaw

   "Ultra-low" Q value $\beta$ decays are referred to as such due to their low decay energies of less than $\sim$1 keV. Such a low energy decay is possible when the parent nucleus decays into an excited state in the daughter, with an energy close to that of the Q value. These decays are of interest as potential new candidates for neutrino mass determination experiments and as a testing ground for studies of atomic interference effects in the nuclear decay process. In this paper, we provide an updated evaluation of atomic mass data and nuclear energy level data to identify potential ultra-low Q value $\beta$ decay candidates. For many of these candidates, more precise and accurate atomic mass data is needed to determine if the Q value of the potential ultra-low decay branch is energetically allowed and in fact ultra-low. The precise atomic mass measurements can be achieved via Penning trap mass spectrometry.

   nucl-exPRC(2023)·25 citations
2. 02*

   Neutron skin in ${}^{48}$Ca determined from p+${}^{48}$Ca and ${}^{48}$Ca+${}^{12}$C scattering

   Shingo Tagami · Tomotsugu Wakasa🇯🇵 · Maya Takechi🇩🇪 · Jun Matsui · Masanobu Yahiro🇯🇵

   In our previous paper, we determined $r_{\mathrm{skin}}^{208}(\exp )=0.278\pm 0.035$~fm from ${\sigma }_{\mathrm{R}}$ for p+${}^{208}$Pb scattering, using the Kyushu (chiral) $g$-matrix folding model with the densities calculated with D1S-GHFB with the angular momentum projection (AMP). The value agrees with that of PREX2. Reaction cross sections ${\sigma }_{\mathrm{R}}$ are available for p+${}^{48}$Ca scattering, whereas interaction cross sections ${\sigma }_{\mathrm{I}}$ are available for ${}^{48}$Ca + ${}^{12}$C scattering. As for ${}^{48}$Ca, the high-resolution $E1$ polarizability experiment ($E1$pE) yields $r_{\mathrm{skin}}^{48}(E1\mathrm{pE})=0.14\sim 0.20\mathrm{fm}$. We determine $r_{\mathrm{skin}}^{48}(\exp )$ from the data on ${\sigma }_{\mathrm{R}}$ for p+${}^{48}$Ca scattering and from the data on ${\sigma }_{\mathrm{I}}$ for ${}^{48}$Ca+${}^{12}$C scattering. We use the Kyushu $g$-matrix folding model with the densities calculated with the D1M-GHFB+AMP densities. The D1M-GHFB+AMP proton and neutron densities are scaled so as to reproduce the data under the condition that the radius $r_{\mathrm{p}}$ of the scaled proton density equals the data $r_{\mathrm{p}}(\exp )$ determined from the electron scattering. We deduce skin values $r_{\mathrm{skin}}=r_{\mathrm{n}}(\exp )-r_{\mathrm{p}}(\exp )$ from the resulting $r_{\mathrm{n}}(\exp )$ and the $r_{\mathrm{p}}(\exp )$ determined from electron scattering. The same procedure is taken for D1S-GHFB+AMP. We regard $r_{\mathrm{skin}}^{48}(E1\mathrm{pE})$ as a reference skin value. Using the reference skin value and taking D1M-GHFB+AMP, we determine $r_{\mathrm{skin}}^{48}(\exp )=0.158\pm 0.025$~fm for p+${}^{48}$Ca scattering and $0.160\pm 0.058$~fm for ${}^{48}$Ca + ${}^{12}$C scattering. We take the weighted mean and its error for the two skin values. The result is $r_{\mathrm{skin}}^{48}(\exp )=0.158\pm (0.023{)}_{\exp }\pm (0.012{)}_{\mathrm{th}}\mathrm{fm}$.

   ↳ nucl-thnucl-ex6 citations
3. 03*

   Neutron availability in the Complementary Experiments Hall of the IFMIF-DONES facility

   Jason Hirtz🇫🇷 · Alain Letourneau🇫🇷 · Loïc Thulliez🇫🇷 · Angel Ibarra🇪🇸 · Wojciech Krolas🇵🇱 · Adam Maj🇵🇱

   The IFMIF-DONES facility will be dedicated to the irradiation of structural materials planned for the use in future fusion reactors such as DEMO (Demonstration Fusion Power Plant). The potentialities of the IFMIF-DONES facility to complement its principal purpose by other experiments that would open the facility to other communities is addressed in this work. It concerns a study based on simulations to evaluate the neutronic performances of IFMIF-DONES in an hall dedicated to complementary experiments where neutrons can be transported. With the simple beam tube geometry of 4.5~cm entrance diameter studied in this work we have shown that a collimated fast-neutron beam of about 2~10${}^{10}$~n/cm${}^2$/s is available in the hall. Adding a moderator in the hall with neutron extraction lines would allow to get thermal neutron beams of about ~10${}^6$-10${}^7$~n/cm${}^2$/s for dedicated experiments. The results show that IFMIF-DONES has the potentialities to be a medium-flux neutron facility for most of the neutron applications.

   ↳ physics.acc-phnucl-exFusion Eng.Des.(2022)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.