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Study of the 32 S( p,p ‘ γ ) 32 S reaction f or resonant PIGE applications. Anastasios Lagoyannis Tandem Accelerator Laboratory Institute of Nuclear and Particle Physics N.C.S.R. “ Demokritos ”. Outline. The 32 S( p,p ’ γ) 32 S case Experimental Setup Experimental Procedure
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Study of the 32S(p,p‘γ)32S reaction for resonant PIGE applications AnastasiosLagoyannis Tandem Accelerator Laboratory Institute of Nuclear and Particle Physics N.C.S.R. “Demokritos”
Outline • The 32S(p,p’γ)32S case • Experimental Setup • Experimental Procedure • Excitation functions, Yield and N– Resonant Cross Section • Resonances • Conclusions - Open Questions • Future Plans A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
The 32S(p,p’γ) 32SCase 32S(p,p’γ) 32SFirst Excited Εγ = 2230 keV Previous Works: J. W. Olness et al. Phys. Rev. 112 (1958), 1702 Resonances & Relative Yield Angle: 8 angles Energy range : 2.7 – 4.0 MeV Target: ~ 20 & 50 keV SbS3 C. Tsartsarakos et al. NIM B45 (1990), 33 Resonant & Non Resonant Cross sections Angle: 90o Energy range : 3.0 – 4.0 MeV Target: ~ 14 keVCdS P. Rao et al. NIM B269 (2011), 2557 Resonances & Resonant Cross sections Angle: 0o & 90o Energy range : 3.0 – 4.0 MeV Target: Thick ZnS pellets C. Tsartsarakos et al. NIM B45 (1990), 33 A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
The 32S(p,p’γ) 32SCase Our Experimental Conditions Resonances – Resonant & Non Resonant Cross sections Angle: 55o - 90o – 125o Plus 0o - 15o – 155o on selected energies Current: 10 to 50 nA Energy range : 3.07 – 6.0 MeV for thin target 3.3, 3.6, 3.9, 4.4, 4.6, 5.26 and 6 MeV for thick target Energy step : Varying from 20 to 2 keV Target: 14 keV MoS2 on Carbon backing Thick CdS pellet for Benchmarking A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Experimental Setup • Electronically controlled turntable • Initial angles: 0o – 55o – 90o - 165o • 4 HPGe detectors (1 – 80%, 3 – 100%) • placed between 25 and 30 cm from target • (Lost 1 before measurement) • Final Angles: 0o – 55o - 125o • Si detector for target/charge monitoring • Air cooled target • NIM electronics • Singles Fast ADC DAQ A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Target Preparation Requirements • Thin target i.e. Self – supported / Thin substrate • Chemical and Thermal stability • Electrical conductivity • Act as charge reference Trial by error: • TiS on Carbon Foil Inhomogeneous • Pure S on Carbon Unstable to Heat • CdS on Ta/C Low Adhesivity Evaporator @ I.N.P. P. Demokritos Solution: MoS2 + 10% IsoPropanol sprayed on Carbon Foil using Airbrush A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Experimental Procedure Detectors’ Energy and Efficiency calibration Machine Calibration Using calibrated 152Eu and 226Ra point sources (it also includes the ΔΩ) Using the 27Al(p,γ)28Si resonance @ 991.6 keVand 13C(p,γ)14Ν @ 1478keV A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Excitation Function Detector @ 55 relative yield up to 6 MeV Raw Data also for detectors @ 90 and 125 not yet analyzed A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Non Resonant Cross sections Detector @ 0, 55 & 125 yields up to 4 MeV Cross sections are valid ONLY for Non – Resonant regions A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Non Resonant Cross sections Comparison with previous data A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Resonance Analysis Analysis of 4 resonances for Detectors @ 0 – 15 – 55 – 90 – 125 - 155 Code used: SPACES by I. Vickridge Inputs Energy of Resonance Stopping Power Doppler broadening Ripple Outputs Resonance Width Target’s thickness A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Resonance Analysis Energy of the Resonances Width of the Resonances A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Angular Distributions J. W. Olness et al. Phys. Rev. 112 (1958), 1702 A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Resonance Cross Section Comparison with previous works Possible explanations Strong angular dependence not taken into account by previous works C. Tsartsarakos et al. Angle uncertainty: ± 30o Angle uncertainty: ± 20o P. Rao et al. Present Work Angle uncertainty: ± 10o A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Conclusions – Open Questions • Yields for 3 angles from 3 to 4 MeV • Is it worth analyzing up to 6 MeV ? • 4 resonances suitable for r – PIGE studied • Angular distributions on resonances imperative • Data for benchmarking acquired – Should be analyzed • Appropriate software for validation A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Latest News … Just measured 27Al(p,p’γ)27Al reaction Angles: 0o - 55o - 90o - 165o Energy range : 2500 – 5000 keV Target of 3 keV Excitation Function A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
Collaborators A. Axiotis, V. Paneta, K. Preketes - Sigalas and S. Harissopulos M. Kokkoris P. Misaelides A. Lagoyannis Institute of Nuclear and Particle Physics NCSR “Demokritos”
