Download presentation
Presentation is loading. Please wait.
Published byTimothy Owens Modified over 4 years ago
1
Nuclear Burning in Stars (E star ) ( E ) = S(E) e –2 E -1 Reaction Rate(star) (E) (E) dE Gamow Peak Maxwell Boltzmann Extrap.Meas. LUNA results Men in pits or wells sometimes see the stars…. Aristotle Carlo Broggini, INFN-Pd
2
INFN - Laboratori Nazionali del Gran Sasso D.Bemmerer,R.Bonetti,C.Broggini*,F. Confortola,P.Corvisiero,H.Costantini,Z.Elekes, A.Formicola, Z. Fülöp, G.Gervino,A.Guglielmetti, C.Gustavino, G. Gyurky, G. Imbriani, M.Junker, A.Lemut, B.Limata, V.Lozza,M.Marta,R.Menegazzo, P.Prati, V.Roca, C.Rolfs, M.Romano, C.RossiAlvarez, O.Straniero,F.Strieder, E.Somorjai,F.Terrasi,H.P.Trautvetter INFN : Genova, LNGS, Milano, Napoli, Padova, Torino Inst.Physik mit Ionenstrahlen, Ruhr- Universität Bochum (GE) Atomki Debrecen (Hungary) LUNA
3
luna Voltage Range :50-400 kV Output Current: 1 mA (@ 400 kV) Absolute Energy error ±300 eV Beam energy spread: <100 eV Long term stability (1 h) : 5 eV Terminal Voltage ripple: 5 Vpp Ge detector F = 0.7 m -2 h -1 FnFn 3 10 -6 cm -2 s -1
4
p + p d + e + + e d + p 3 He + 3 He + 3 He +2p 3 He + 4 He 7 Be + 7 Be+e - 7 Li + + e 7 Be + p 8 B + 7 Li + p 8 B 2 + e + + e 84.7 %13.8 % 13.78 % 0.02% pp chain
5
14 N(p, g ) 15 O Q=7.3 MeV - 504 -21 278 14 N+p 7297 7556 7276 6859 6793 6176 5241 5183 0 15 O 1/2 + 7/2 + 5/2 + 3/2 + 3/2 - 5/2 + 1/2 + 1/2 -
6
10 -7 mbar10 -6 mbar10 -4 mbar 0.5-2 mbar Windowless gas-target Max 10 mbar Low energy: gas target + BGO
7
Reaction Rate = 10.95 0.83 counts/day Background rate = 21.14 0.75 counts/day t = 49.12 daysQ = 927 7 C beam energy: 80 keV
8
cno from the Sun Globular cluster age C yield in AGB stars S t (0)=1.61±0.08±0.16 keV b
9
3 He(, g ) 7 Be Solar Neutrinos: 7 Be, 8 B BBN 7 Li prompt gammaCross section from prompt gamma down to 90 keV (CM energy) using 4 He beam on 3 He target radioactive decayActivation via off-line radioactive decay measurements of the 7 Be atoms collected in the beam catcher All with a final error < 5 % Q=1.6 MeV
10
Summary of previous measurements = 0.51 ± 0.02 keV b = 0.57 ± 0.03 keV b 0.53 ± 0.05 keV b (9%) [Adelberger 98] 0.54 ± 0.09 keV b (16%) [NACRE 99] Recommended S 34 (0) values: R-matrix analysis: 0.51 ± 0.04 keV b (8%) [Descouvemont 2004]
13
Activation measurement o 4 He beam @ 350 keV o ~ 230 µA oRecirculated 3 He @ 0.7 mbar 478 214 Bi 7 Be
14
SourceDeterminationRelative Uncertainty Detector efficiencyMeasured1.8 % Beam currentCalibrated calorimeter1.5 % Beam heating effectMeasured (typical correction: 5%) 1.3 % Target thicknessPressure and temperature measurements 0.6 % Backscattering lossMeasured and simulated (typical correction: 2.1%) 0.5 % 478 keV -ray branchingFrom literature0.4 % Incomplete 7 Be collectionMeasured and simulated (typical correction: 1.6%) 0.4% Effective energyMeasured0.5-0.8 % Parasitic 7 Be productionMeasured upper limit0.04 % Sputtering lossUpper limit from MC Simulation0.02 % Total3.0 % Systematic uncertainties and corrections
17
Prompt -spectra o 4 He beam @ 400 keV o ~ 300 µA oIrradiation time: 4.4d o 4 He beam @ 220 keV o ~ 240 µA oIrradiation time: 24.4d
18
3 He(, g ) 7 Be: the Sun: 7 Be and 8 B neutrinos Big-Bang 7 Li 14 N(p, g ) 15 O: down to 70 keV (T=60 T 6 ) cno from the Sun reduced by 2 Globular cluster age increased by 0.7-1 Gy Higher C yield in AGB stars LUNA has shown that it is possible to measure (E star ): 3 He ( 3 He,2p) 4 He, 2 H(p, g ) 3 He 3 He ( 3 He,2p) 4 He: down to 16 keV no resonance within the solar Gamow Peak
20
S 14,1 /5 S 14,1 x5 Standard CF88
22
25 Mg(p, g ) 26 Al Q=6.3 MeV Nucleosynthesis Mg-Al Astronomical interest of the from 26 Al decay Ge detectorsCross section at 180-400 keV (CM energy) using Ge detectors (not underground) BGO summing crystalsCross section at lower energies using BGO summing crystals (underground)
Similar presentations
© 2018 SlidePlayer.com Inc.
All rights reserved.
Doc convert to ppt online reader Free download ppt on transportation in plants Ppt on group discussion topics Ppt on obesity prevention cdc Free download ppt on energy resources Solving equations ppt one step Ppt on computer manners Ppt on file system in unix the lowest Ppt on series and parallel combination of resistors experiment Ppt on job rotation examples