Silicon Characterization for DAPPER Austin Abbott Texas AM

Silicon Characterization for DAPPER Austin Abbott Texas A&M Cyclotron Institute DNP 2020

INTEGRAL (cosmos. esa) E. Uberseder et al. PRL 102, 151101 (2009) • 60 Fe produced in massive stars • 60 Fe/26 Al gamma flux – calibration point • Various models disagree • Uncertainty in 59 Fe(n, γ)60 Fe cross-section contributes S. W. Jones et al. MNRAS 485, 4287 -4310 (2019) 1

Photon Strength Function 57 Fe 56 Fe Transmission coefficient Photon strength function • Low energy enhancement in PSF for 56, 57 Fe not predicted by models • An enhancement could indicate an increase in the reaction rate of neutron-rich nuclei A. Voinov et al. Phys. Rev. Lett. Vol. 93, 14 (2004) 2

DAPPER: Detector Array for Photons, Protons, and Exotic Residues • • Silicon CD 2 Target 128 Ba. F 2 YAP: Ce array 3

Silicon Detector • S 3 Micron Annular Silicon • ~500 μm • 24 rings • 32 segments or “pies” CD 2 www. micronsemiconductor. co. uk Si Y Pos • Covers 120 -150 degrees X Pos 4

57 Fe(d, pγ)58 Fe Yield Proton Energy (Me. V) Multiplicity 1 and Segment gate Excitation Energy (Me. V) θ (degrees) 1674 ke. V 810 ke. V Excitation Energy (Me. V) θ (degrees) 5

FWHM (Me. V) All on All off * RF Magnets V Filter Valves *A beam of 40 Ar was directed to slits of MARS coffin Ring Number Run number Run Number • Cyclotron effect on resolution • RF • MARS magnets • Velocity filter E field • Valves 6

Simulations • • Beam energy Detector resolution – (100 ke. V FWHM) • Angular resolution and coverage Yield – (1. 25 deg theta, 11. 25 deg in phi) • Energy loss in target – 905 μg/cm 2 • Energy loss in dead layer – 0. 8 micron aluminum Yield Excitation Energy (Me. V) Beam spot size 5 mm -> 0. 3 mm 600 ke. V -> 380 ke. V Excitation Energy (Me. V) 7

Summary • Interesting structure in PSF for iron isotopes • DAPPER built to measure PSF • Silicon detector gives measurement of the excitation energy • Can achieve improvement in resolution with position sensitivity 8

Thanks Max Sorensen Aaron Couture Alan B. Mc. Intosh Kris Hagel Jerome Gauthier Shuya Ota Anna Simon This research is possible thanks to the NNSA Grant #DENA 0003841, Robert A. Welsh Foundation Grant #A-1266 and Department of Energy Grant #DE-FG 02 -93 ER 40773.