BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Development of a spectrometry system for measurement of internal-p air studies DTSTART;VALUE=DATE-TIME:20190320T084500Z DTEND;VALUE=DATE-TIME:20190320T090000Z DTSTAMP;VALUE=DATE-TIME:20260811T104856Z UID:indico-contribution-1343@indico.tlabs.ac.za DESCRIPTION:Speakers: Maluba Vernon J. Chisapi (iThemba LABS/Stellenbosch University)\nExcited nuclei eventually de-excites mainly through electroma gnetic transitions\, e.g. gamma-ray transitions or electric monopole (E0) transition in an event that the former is forbidden. E0 transitions procee d via conversion electrons and electron-positron pairs (for transition ene rgies > 1022 keV). Compared to gamma-ray transitions that are predominantl y studied across the chart of nuclides\, a great deal of E0 transitions an d their associated excited 0+ states are still not firmly characterized.\n \nApart from being the only alternative means of unambiguously assigning s pin and parity to states\, E0 transitions also offer a reliable thumbprint for shape coexistence in nuclei\, as the E0 transition strength can be us ed in the calculation of the mixing parameters for shapes suspected to be coexisting. Measurements of E0 transitions also helps elucidate phenomena relating to nuclear compressibility and isotope and isomer shift as well a s provide sensitive tests on various models of nuclear structure [1][2][3] [4].\n\nA new facility\, namely the electron spectrometer\, for measuring E0 transitions was recently commissioned at iThemba Laboratory for Acceler ator Based Sciences (LABS). The current work is aimed at giving the equipm ent new capability by adapting a segmented germanium (LEPS) detector into the spectrometer in order for it to be used to measure e-/e+ pairs of high er (> 3 MeV) energies as well. The LEPS detector is opted for owing to the scarcity (or exorbitant prices if found) of thick segmented Si(Li) detect ors around the globe. The refurbishment is being aided by Geant4 simulatio ns with magnetic field mapped out of the solenoid magnetic lens using OPER A-3D software [5]. The Transmission\, efficiency\, momentum resolution and other parameters of the spectrometer\, obtained using Geant4 simulations\ , will be presented. On-going investigation on the feasibility of using a LEPS detector to measure internal pairs will also be discussed.\n\nOnce th e facility is fully operational\, the physics case will involve measuring E0 transitions in 50Ti\, which will provide information that will subseque ntly be used to investigate the previously suspected existence of admixtur es of 0+ excited states with 2+\, 3+ and 4+ states [6][7][8].\n\nReference s\n[1] Michael Taylor et al. A triplet of differently shaped spin-zero sta tes in the atomic nucleus 186Pb. Nature\, 405:430{433\, 5 2000.\n[2] JL Wo od et al. Coexistence in even-mass nuclei. Physics Reports\, 215(3-4):101{ 201\, 1992.\n[3] Tibor Kibedi and Ray H Spear. Electric monopole transitio ns between 0+ states for nuclei throughout the periodic table. Atomic Data and Nuclear Data Tables\, 89(1):77{100\, 2005.\n[4] JL Wood et al. Electr ic monopole transitions from low energy excitations\nin nuclei. Nuclear Ph ysics A\, 651(4):323{368\, 1999.\n[5] Opera Electromagnetic FEA Simulation Software. Opera-3D software. [Online]. https://operafea.com/\, [Accessed: 28 December 2018].\n[6] DS Oakley et al. Pion elastic and inelastic scatt ering from 48\;50Ti\, 52Cr\,\nand 54\;56Fe at 180 MeV: Determination of ne utron and proton multipole matrix elements. Physical Review C\, 35(4):1392 \, 1987.\n[7] JG Pronko et al. gamma-ray deexcitation of Ti 50 states in t he region of 4-MeV excitation. Physical Review C\, 10(4):1345\, 1974.\n[8] HP Morsch. Monopole transitions in the inelastic 3He-scattering on Ti-iso topes. Physics Letters B\, 47(1):21{23\, 1973.\n\nhttps://indico.tlabs.ac. za/event/82/contributions/1343/ LOCATION:J Block Auditorium URL:https://indico.tlabs.ac.za/event/82/contributions/1343/ END:VEVENT END:VCALENDAR