Mon·Aug 16, 2021Monday·August 16, 2021

1. 01*

   The 27Al(p,a)24Mg reaction at astrophysical energies studied by means of the Trojan Horse Method applied to the 2H(27Al,a24Mg)n reaction

   Sara Palmerini · Marco La Cognata · Fairouz Hammache · Luis Acosta · Rosa Alba · Vaclav Burjan · Efrain Chavez · Silvio Cherubini · Alexandra Cvetinovic · Giuseppe D'Agata · Nicolas De Sereville · Alessia Di Pietro and 24 other authors

   The 27Al(p,a)24Mg reaction, which drives the destruction of 27Al and the production of 24Mg in stellar hydrogen burning, has been investigated via the Trojan Horse Method (THM) by measuring the 2H(27Al,a24Mg)n three-body reaction. The experiment covered a broad energy range (-0.5 MeV < E_cm < 1.5 MeV), aiming to investigate those of interest for astrophysics.The results confirm the THM as a valuable technique for the experimental study of fusion reactions at very low energies and suggest the presence of a rich pattern of resonances in the energy region close to the Gamow window of stellar hydrogen burning (70-120 keV), with potential impact on astrophysics. To estimate such an impact a second run of the experiment is needed, since the background due the three-body reaction hampered to collect enough data to resolve the resonant structures and extract the reaction rate.

   nucl-exastro-ph.SREur.Phys.J.Plus(2021)·7 citations
2. 02*

   Alpha-decay-correlated mass measurement of 206,207Ra using an $\alpha$-TOF detector equipped MRTOF-MS system

   T. Niwase · M. Wada🇵🇱 · P Schury🇯🇵 · P. Brionnet🇫🇷 · S. D. Chen🇺🇸 · T. Hashimoto🇯🇵 · H. Haba🇯🇵 · Y. Hirayama · D. S. Hou · S. Iimura · H. Ishiyama · S. Ishizawa and 16 other authors

   The atomic masses of the isotopes ${}^{206,207}$Ra have been measured via decay-correlated mass spectroscopy using a multi-reflection time-of-flight mass spectrograph equipped with an $\alpha$-TOF detector. The Ra isotopes were produced as fusion-evaporation products in the ${}^{51}$V+${}^{159}$Tb reaction system and delivered by the gas-filled recoil ion separator GARIS-II at RIKEN. The $\alpha$-TOF detector provides for high-accuracy mass measurements by correlating time-of-flight signals with subsequent $\alpha$-decay events. The masses of ${}^{206}$Ra and ${}^{207g,m}$Ra were directly measured using a multi-reflection time-of-flight mass spectrograph equipped with an $\alpha$-TOF detector. A mass excess of ME = 3538(15) keV/c${}^2$ and an excitation energy of E${}_{\mathrm{ex}}$ = 552(42) keV were determined. The $\alpha$-decay branching ratio of ${}^{207m}$Ra, b$\alpha$ = 0.26(20), was directly determined from decay-correlated time-of-flight signals, and the reduced alpha width of ${}^{207m}$Ra was calculated to be ${\delta }^2$ = 50+62-41 keV from the branching ratio. The spin-parity of ${}^{207m}$Ra was confirmed to be $J^{\pi }$ = 13/2${}^{-}$ from decay correlated mass measurement results.

   nucl-exPRC(2021)·4 citations
3. 03*

   High-precision nuclear chronometer for the cosmos

   X. H. Wu🇨🇳 · P. W. Zhao🇨🇳 · S. Q. Zhang🇨🇳 · J. Meng🇨🇳

   Nuclear chronometer, which predicts the ages of the oldest stars by comparing the present and initial abundances of long-lived radioactive nuclides, provides an independent dating technique for the cosmos. A new nuclear chronometer called Th-U-X chronometer is proposed, which imposes stringent constraints on the astrophysical conditions in the $r$-process simulation by synchronizing the previous Th/X, U/X and Th/U chronometers. The astrophysical uncertainties of nuclear chronometer are significantly reduced from more than $\pm 2$ billion years to within 0:3 billion years by the Th-U-X chronometer. The proposed chronometer is then applied to estimate the ages of the six metal-poor stars with observed uranium abundances, and the predicted ages are compatible with the cosmic age 13.8 billion years predicted from the cosmic microwave background radiation, but in contradictory with the new cosmic age 11.4 billion years from the gravitational lenses measurement.

   ↳ nucl-thastro-ph.COastro-ph.IMnucl-exApJ(2022)·13 citations
4. 04*

   The Florence Trigger-Box (FTB) project: an FPGA-based configurable and scalable trigger system

   Pietro Ottanelli🇮🇹 · Gabriele Pasquali · Lucia Baldesi🇮🇹 · Sandro Barlini🇮🇹 · Riccardo Bolzonella🇮🇹 · Alberto Camaiani🇮🇹 · Giovanni Casini🇮🇹 · Caterina Ciampi🇮🇹 · Tommaso Marchi🇮🇹 · Silvia Piantelli🇮🇹 · Simone Valdre'🇮🇹 · Giuseppe Verde🇮🇹

   A multi-layer trigger system, based on programmable logic devices hosted on VME boards, has been implemented. It is completely scalable and suitable for handling from a few up to a few hundred channels. Custom software for monitoring and controlling the trigger system has been developed.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2021)·2 citations

* 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.