Update of High Resolution (e,e'K^+) Hypernuclear Spectroscopy at Jefferson Lab's Hall A

Updated results of the experiment E94-107 hypernuclear spectroscopy in Hall A of the Thomas Jefferson National Accelerator Facility (Jefferson Lab), are presented. The experiment provides high resolution spectra of excitation energy for 12B_\Lambda, 16N_\Lambda, and 9Li_\Lambda hypernuclei obtained by electroproduction of strangeness. A new theoretical calculation for 12B_\Lambda, final results for 16N_\Lambda, and discussion of the preliminary results of 9Li_\Lambda are reported.Comment: 8 pages, 5 figures, submitted to the proceedings of Hyp-X Conferenc

Shell-model calculations for p-shell hypernuclei

The interpretation of hypernuclear gamma-ray data for p-shell hypernuclei in terms of shell-model calculations that include the coupling of Lambda- and Sigma-hypernuclear states is briefly reviewed. Next, Lambda 8Li, Lambda 8Be, and Lambda 9Li are considered, both to exhibit features of Lambda-Sigma coupling and as possible source of observed, but unassigned, hypernuclear gamma rays. Then, the feasibility of measuring the ground-state doublet spacing of Lambda 10Be, which, like Lambda 9Li, could be studied via the (K-,pi0 gamma) reaction, is investigated. Structural information relevant to the population of states in these hypernuclei in recent (e,e'K+) studies is also given. Finally, the extension of the shell-model calculations to sd-shell hypernuclei is briefly considered.Comment: 17 pages, 3 figures. Contribution to special volume on Strangeness Nuclear Physic

High-Resolution Spectroscopy of Λ(16)N by Electroproduction

An experimental study of the 16O(e,e′K+)Λ16N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e′K+)Λ,Σ0 exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76±0.16  MeV was obtained for Λ16N with better precision than previous measurements on the mirror hypernucleus Λ16O. Precise energies have been determined for peaks arising from a Λ in s and p orbits coupled to the p1/2 and p3/2 hole states of the 15N core nucleus

Optimization of the sheet hydroforming process parameters to improve the quality of reshaped EoL components

The reshaping of End-of-Life (EoL) components by means of sheet metal forming process has been considered largely attractive, even from the social and economic point of view. At the same time, EoL parts can be often characterized by non-uniform thicknesses or alternation of work-hardened/undeformed zones as the results of the manufacturing process. Such heterogeneity can hinder a proper reshaping of the EoL part and residual marks on the re-formed blanks can be still present at the end of the reshaping step. In a previous analysis, the authors evaluated the effectiveness of reshaping a blank with a deep drawn feature by means of the Sheet Hydroforming (SHF) process: it was demonstrated that residual marks were still present if the deep drawn feature was located in a region not enough strained during the reshaping step. Starting from this condition and adopting a numerical approach, additional investigations were carried out changing the profile of the load applied by the blankholder and the maximum oil pressure. Numerical results were collected in terms of overall strain severity and residual height of the residual marks from the deep drawn feature at the end of the reshaping step. Data were then fitted by accurate Response Surfaces trained by means of interpolant Radial Basis Functions, subsequently used to carry out a virtual optimization managed by a multi-objective genetic algorithm. Optimization results suggested the optimal value of the output variables to reduce the marks from the deep drawn feature without the occurrence of rupture

Design, Construction, Operation and Performance of a Hadron Blind Detector for the PHENIX Experiment

A Hadron Blind Detector (HBD) has been developed, constructed and successfully operated within the PHENIX detector at RHIC. The HBD is a Cherenkov detector operated with pure CF4. It has a 50 cm long radiator directly coupled in a window- less configuration to a readout element consisting of a triple GEM stack, with a CsI photocathode evaporated on the top surface of the top GEM and pad readout at the bottom of the stack. This paper gives a comprehensive account of the construction, operation and in-beam performance of the detector.Comment: 51 pages, 39 Figures, submitted to Nuclear Instruments and Method

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