Thu·Dec 8, 2016Thursday·December 8, 2016

1. 01*

   Improved Pulse Shape Discrimination in EJ-301 liquid scintillators

   R.F. Lang🇺🇸 · D. Masson🇺🇸 · J. Pienaar🇺🇸 · S. Röttger🇩🇪

   Digital pulse shape discrimination has become readily available to distinguish nuclear recoil and electronic recoil events in scintillation detectors. We evaluate digital implementations of pulse shape discrimination algorithms discussed in the literature, namely the Charge Comparison Method, Pulse-Gradient Analysis, Fourier Series and Standard Event fitting. In addition, we present a novel algorithm based on a Laplace Transform. Instead of reducing the performance of these algorithms to a single Figure of Merit, we evaluate them as function of recoil energy. Specifically, using commercial EJ-301 liquid sctintillators, we examine both the resulting acceptance of nuclear recoils at a given rejection level of electronic recoils, as well as the purity of the selected nuclear recoil event samples. We find that both a Standard Event fit and a Laplace Transform can be used to significantly improve the discrimination capabilities over the whole energy range. Furthermore, we show that the Charge Comparison Method performs poorly in accurately identifying nuclear recoils.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2017)·8 citations
2. 02*

   Cluster states in stable and unstable nuclei

   M. Kimura🇯🇵

   In this contribution, I will discuss two topics related to the clustering of atomic nuclei. The first is dual character of the ground state. Recently, it was pointed out that the ground states of atomic nuclei have dual character of shell and cluster implying that both of the single-particle excitation and cluster excitation occur as the fundamental excitation modes. The isoscalar monopole and dipole transitions are regarded as the triggers to induce the cluster excitation. By referring the Hartree-Fock and antisymmetrized molecular dynamics calculations, the dual character and those transitions are explained. The second is the linear-chain state of ${}^{16}\mathrm{C}$ in which the linearly aligned 3$\alpha$ particles are sustained by the valence neutrons. The rather convincing evidences for this exotic state are very recently reported by several experiments. Here, I introduce a couple of theoretical analysis and predictions.

   ↳ nucl-thnucl-ex2 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.