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Delayed Neutron Emission Induced by 800 MeV Protons. Steven Greene, LANL 11/14/2007. Slide 1. LANL Research Team. Chris Morris, P-25 ( Principal Investigator ) Steve Greene, P-25 Mark Makela, P-25 David Clark, P-22 Randy Spaulding, ISU Fesseha Mariam, P-25 Lori Waters, D-5
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Delayed Neutron Emission Induced by 800 MeV Protons Steven Greene, LANL 11/14/2007 Slide 1
LANL Research Team Chris Morris, P-25 (Principal Investigator) Steve Greene, P-25 Mark Makela, P-25 David Clark, P-22 Randy Spaulding, ISU Fesseha Mariam, P-25 Lori Waters, D-5 Jay Elson, D-5 Greg Canavan, P-DO Slide 2
Experimental Setup - OL Station Target ladder for small “bare” targets Vacuum Beam Pipe He3 detector and LaBr detector 34-in target distance
Delayed Neutrons on 10s of ms time scale Room return
Delayed Cross Sections vs. Z • Delayed neutrons from Pb, Hg, Au appear to arise from fission. • 18O has the highest delayed neutron production of all targets measured. • Typical background materials like iron and Aluminum have cross sections ~1/100th of Uranium
Experimental Setup - IL2 station Ladder DU: 1”x4”x4” Shielding Water, Al, Steel, Pb Various thicknesses Null Proton Beam centerline 22.50 Pb: 2”x4”x8” Quad He3 detector 315-cm target distance 310 He3 detector and LaBr detector 173-cm target distance 440
Shielding • Material density thickness* • No shielding (air) 0.1 g/cm2 • Aluminum 27.4 g/cm2 4” • Steel 81 g/cm2 4” • Water 30.4 g/cm2 12” • Polyethylene (CH2) 29.5 g/cm2 12.5” • Sand (SiO2) 44.7 g/cm2 8” • Lead 229.6 g/cm2 8” *minimum linear thickness of materials --protons & neutrons traveled through materials at an angle of 22.50