Gamma Efficiency Simulations for Coincident Fusion Cross Section Measurements

Transcription

1 Gamma Efficiency Simulations for Coincident Fusion Cross Section Measurements ANSRI 2016 Marcel Heine for the STELLA Collaboration CNRS Strasbourg 5/13/2016

2 Outlook 1 Deep Sub-barrier Fusion Cross Sections S-Factor Measurements of 12 C+ 12 C Reactions Coincident Gamma Charged-Particle Technique 2 Experimental Setup Mobile Gamma Charged Particle Detection System ANDROMEDE Accelerator 3 Simulation Software for STELLA LaBr 3 Detector Implementation Efficieny Simulations of 36 LaBr 3 Detectors Self Activity of LaBr 3 Crystals 4 Summary and Outlook

3 S-Factor Measurements of 12 C+ 12 C Reactions 17 Gamow window 16 S [MeVb] Barron-Palos et al., (2006) Fruet, PhD project Zickefoose et al., (20) Mazarakis et al., (1973) Gasques et al. (2005) Jiang et al. (2007) E rel [MeV] exp (-kt) Gamow window Energy [a.u.] barrier S = Eσ(E)exp(2πη) Gamow window: fusion cross sections in the order of nbarn extremely sensitive to background contributions gamma-particle (coincidence) technique

4 Coincident Gamma Charged-Particle Technique Particle spectrum (deg) θ lab C,p) d( C C( C,p) Na E (4kev/channel) 1 G. Fruet, PhD project, ANL, 2015 X. Fang et al., Jour. Phys., 420, , 2013 efficient background reduction normalization

5 Coincident Gamma Charged-Particle Technique Coincidence with E γ = 440 kev (deg) θ lab C,p) d( C C( C,p) Na E (4kev/channel) G. Fruet, PhD project, ANL, 2015 X. Fang et al., Jour. Phys., 420, , 2013 efficient background reduction normalization

6 Motivation Experimental Setup Mobile Gamma Charged Particle Detection System particles: 3 DSSSD gammas: 36 LaBr3 (Ce) M. Krauth, P. Dene Simulation Summary and Outlook

7 ANDROMEDE Accelerator 4 MV Van de Graaff Accelerator at IPN, Orsay (France) commissioned Jan.-March C intensity: 5- pµa considerable beamtime available

8 LaBr 3 Detector Implementation standard G4 constructors physics list: QGSP BIC HP dose assignment to sensitive volumes I/O via ROOT P. Regan, IASEN, 2014 crystal: = 1.5, l = 2 PMT: = 2, l 8 DAQ read out electronics HV modules

9 Efficieny Simulations of 36 LaBr 3 Detectors Yield [Counts] 137 Cs on CsI crystals 220 Entries Mean RMS Underflow 30 Overflow Integral 2.449e geometrical acceptance photo-peak efficiency compactness feasibility (construction) Channel Geometrical Acceptance [%] Sphere Cylinder Wall G. Heitz

10 Motivation Experimental Setup Simulation Summary and Outlook Efficieny Simulations of 36 LaBr3 Detectors 137 Cs on CsI crystals geometrical acceptance 220 Entries Mean RMS Underflow 30 Overflow 0 Integral 2.449e Yield [Counts] compactness 120 feasibility (construction) Channel Geometrical Acceptance [%] Sphere Cylinder Wall photo-peak efficiency

11 Simulated Photo-Peak Efficiency eff. x acc. [%] GAMMASPHERE E addb [MeV] green: GAMMASPHERE, ANL circles: LaBr 3, STELLA

12 Self Activity of LaBr 3 Crystals T 1/2 = a, nat. ab. = 0.090% A = 90 Bq 66% : 138 La + e 138 Ba + ν e ; E γ = MeV 34% : 138 La 138 Ce + e + ν e ; E γ = MeV 000 beta decay spectrum Yield [Counts] PDF [a.u.] E [kev] E [kev]

13 Approximation of Gamma Background Spectrum: Work in Progess Yield [Counts] γ(p ) 1 γ(α ) green: exponential background blue: simulation E [kev]

14 mechanical design for particle and gamma detectors simulation of characteristic gamma interactions in scintillators efficiency study for gamma detector arrangement self activity model LaBr 3 classify Crystals according to energy resolution and α impurities Thank You For Listening!!