Wed·Mar 21, 2018Wednesday·March 21, 2018

1. 01*

   First determination of $\beta$-delayed multiple neutron emission beyond A = 100 through direct neutron measurement: The P${}_{2n}$ value of ${}^{136}$Sb

   R. Caballero-Folch🇪🇸 · I. Dillmann🇨🇦 · J. Agramunt · J.L. Taín🇪🇸 · A. Algora🇪🇸 · J. Äystö🇫🇮 · F. Calviño🇪🇸 · L. Canete · G. Cortès🇪🇸 · C. Domingo-Pardo🇪🇸 · T. Eronen🇫🇮 · E. Ganioglu🇹🇷 and 25 other authors

   Background: $\beta$-delayed multiple neutron emission has been observed for some nuclei with A$\le$100, with ${}^{100}$Rb being the heaviest $\beta$2n emitter measured to date. So far, only 25 P${}_{2n}$ values have been determined for the $\sim$300 nuclei that may decay in this way. Accordingly, it is of interest to measure P${}_{2n}$ values for the other possible multiple neutron emitters throughout the chart of the nuclides. It is of particular interest to make such measurement for nuclei with A$>$100 to test the predictions of theoretical models and simulation tools for the decays of heavy nuclei in the region of very neutron-rich nuclei. In addition, the decay properties of these nuclei are fundamental for the understanding of astrophysical nucleosynthesis processes such as the $r$-process, and safety inputs for nuclear reactors. Purpose: To determine for the first time the two neutron branching ratio, P${}_{2n}$ value, for ${}^{136}$Sb through a direct neutron measurement, and to provide precise P${}_{1n}$ values for ${}^{136}$Sb and ${}^{136}$Te. Method: Pure beams were provided by the JYFLTRAP at the IGISOL facility of the University of Jyväskylä, Finland. The purified ions were implanted into a moving tape at the end of the beam line. The detection setup consisted of a plastic scintillator placed right behind the implantation point, and the BELEN detector, based on neutron counters embedded in a polyethylene matrix. The analysis was based on the study of the $\beta$- and neutron- growth-and-decay curves and the $\beta$-one-neutron and $\beta$-two-neutron time correlations. Results: The P${}_{2n}$ value of ${}^{136}$Sb was found to be 0.14(3)\% and the measured P${}_{1n}$ values for ${}^{136}$Sb and ${}^{136}$Te were found to be 32.2(15)\% and 1.47(6)\%, respectively. The measured P${}_{2n}$ value is a factor 44 smaller than predicted by the FRDM+QRPA model used for $r$-process calculations.

   nucl-exPRC(2018)·11 citations
2. 02*

   Compton Scattering from the Deuteron above Pion-Production Threshold

   B. Strandberg🇬🇧 · J.R.M. Annand🇬🇧 · W. Briscoe🇺🇸 · J. Brudvik🇸🇪 · F. Cividini🇩🇪 · L. Clark🇬🇧 · E.J. Downie🇺🇸 · K. England🇺🇸 · G. Feldman🇺🇸 · K.G. Fissum🇸🇪 · D.I. Glazier🇬🇧 · K. Hamilton🇬🇧 and 17 other authors

   The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data on light nuclear targets. Recent measurements of the differential cross section for Compton scattering on the deuteron below the pion-production threshold have decreased the uncertainties in the neutron polarizabilities, yet the proton polarizabilities remain known substantially more accurately. As the sensitivity of the cross section to the polarizabilities increases with incident photon energy, measurements above the pion threshold may offer a way for an improved determination of the neutron polarizabilities. In this article, the first measurement of the cross section for Compton scattering on the deuteron above the pion-production threshold is presented.

   nucl-exPRC(2018)·2 citations
3. 03*

   Sensitivity of a low threshold directional detector to CNO-cycle solar neutrinos

   R. Bonventre🇺🇸 · G. D. Orebi Gann🇺🇸

   A first measurement of neutrinos from the CNO fusion cycle in the Sun would allow a resolution to the current solar metallicity problem. Detection of these low-energy neutrinos requires a low-threshold detector, while discrimination from radioactive backgrounds in the region of interest is significantly enhanced via directional sensitivity. This combination can be achieved in a water-based liquid scintillator target, which offers enhanced energy resolution beyond a standard water Cherenkov detector. We study the sensitivity of such a detector to CNO neutrinos under various detector and background scenarios, and draw conclusions about the requirements for such a detector to successfully measure the CNO neutrino flux. A detector designed to measure CNO neutrinos could also achieve a few-percent measurement of pep neutrinos.

   ↳ physics.ins-detastro-ph.SRhep-exnucl-exEPJC(2018)·29 citations
4. 04*

   Design flow for readout ASICs in High-energy Physics experiments

   A. Voronin🇷🇺 · E. Malankin🇷🇺

   In the large-scale high energy physics experiments multi-channel readout application specific integrated circuits (ASICs) are widely used. The ASICs for such experiments are complicated systems, which usually include both analog and digital building blocks. The complexity and large number of channels in such ASICs require the proper methodological approach to their design. The paper represents the mixed-signal design flow of the ASICs for high energy physics. This flow was successfully implemented in the development of the readout ASIC prototypes for the muon chambers of the CBM experiment. The approach was approved in UMC CMOS MMRF 180 nm process. The design flow enables to analyze the mixed-signal system operation on the different levels: functional, behavioral, schematic and post-layout including parasitic elements. The proposed design flow allows reducing the simulation period and eliminating the functionality mismatches on the very early stage of the design.

   ↳ physics.ins-dethep-exnucl-ex0 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.