22 Ne(p, ) 23 Na cross section measurement at astrophysical - - PowerPoint PPT Presentation

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22 Ne(p, ) 23 Na cross section measurement at astrophysical energies Federico Ferraro Universit degli Studi di Genova, INFN Sezione di Genova VIII International Nuclear Physics in Astrophysics Conference, 22 June 2017 Catania,

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VIII International Nuclear Physics in Astrophysics Conference, 22 June 2017 – Catania, Italy

22Ne(p,)23Na cross section

measurement at astrophysical energies

Università degli Studi di Genova, INFN – Sezione di Genova

Federico Ferraro

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Nuclear astrophysics in a nutshell

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STAR INTERSTELLAR GAS MIXING NUCLEAR REACTIONS EJECTION CONDENSATION Isotopic abundances Energy production Nucleosynthesis

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

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The Gamow peak defines the relevant energy range for such reactions to occur Consider a radiative capture reaction x + A  B +  The reaction rate is given by 𝑠 = NxNA

∞

𝜚 𝑤 𝜏 𝑤 𝑤 d𝑤 The cross section in the Gamow peak is small! direct measurements on surface are often hampered by cosmic ray induced background possible solutions: extrapolation, indirect and underground measurements

The Gamow peak

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Something unexpected may exist at low energies!

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It is possible to factorize the cross section 𝜏 𝐹 = 1 𝐹 𝑓−2𝜌𝜃𝑻 𝑭 and extrapolate the astrophysical factor S(E) down to astrophysical energies…

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Something unexpected may exist at low energies!

TAUP 2019

It is possible to factorize the cross section 𝜏 𝐹 = 1 𝐹 𝑓−2𝜌𝜃𝑻 𝑭 and extrapolate the astrophysical factor S(E) down to astrophysical energies… But…

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Something unexpected may exist at low energies!

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It is possible to factorize the cross section 𝜏 𝐹 = 1 𝐹 𝑓−2𝜌𝜃𝑻 𝑭 and extrapolate the astrophysical factor S(E) down to astrophysical energies… unexpected resonances may be present in the extrapolation region! But…

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Direct measurements at low energy are required

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Low cross section means low counting rate Background reduction is fundamental Underground measurements Material selection and cleaning

An example: 22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

The neon-sodium (NeNa) cycle

22Ne(p,)23Na and 23Na(p,)24Mg recently investigated at LUNA

Advanced H-burning cycle (higher temperature w.r.t. pp chain and CNO cycle) Mainly active in TP-AGB stars (Hot Bottom Burning process) Not important for energy production Important for nucleosynthesis (Na/O anticorrelation in GCs)

22Ne 23Na

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na

It was the most uncertain reaction in the NeNa cycle Several low-energy resonances Tentative resonances at very low energy New measurements performed at HZDR, LUNA and TUNL

22Ne(p,)23Na cross section measurement at astrophysical energies

LUNA HZDR

22Ne 23Na

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Federico Ferraro | federico.ferraro@ge.infn.it

The Gran Sasso National Laboratory (LNGS)

Reduction of cosmic-ray-induced background muons:  106 neutrons:  103

Grey: surface Black: LUNA Rock overburden > 1400 m (>3000 m.w.e.)

22Ne(p,)23Na cross section measurement at astrophysical energies

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Image credit: Nature

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Federico Ferraro | federico.ferraro@ge.infn.it

The Laboratory for Underground Nuclear Astrophysics

Electrostatic accelerator 2 beamlines: gas/solid targets Beam energy: 50-400 keV Beam current: up to 1 mA Energy spread: 0.1 keV Stability: 5 eV/h

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Gas target

  • Extended gas target
  • 3 differential pumping stages (no entrance window)
  • Gas recycling and purification
  • Need to measure temperature and pressure profiles -> density profile

~ 1 mbar ~ 10−7 mbar

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

temperature pressure density

(1.3% uncertainty)

Determines:

  • number of

target nuclei

  • energy loss
  • beam current

22Ne(p,)23Na cross section measurement at astrophysical energies

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22Ne gas target (99.9% enriched)

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Federico Ferraro | federico.ferraro@ge.infn.it

Beam calorimeter

𝑈ℎ𝑝𝑢 𝑈𝑑𝑝𝑚𝑒 Power compensation calorimeter Copper cylinder. Hot side, cold side, constant ∆𝑈 2 heat sources: beam and resistors beam OFF – beam ON measurements to calculate the beam power 𝑋

𝑑𝑏𝑚

Systematic uncertainty: 0.5 W 𝑋

𝑑𝑏𝑚 < 30 W

1.5% 𝑋

𝑑𝑏𝑚 ≥ 30 W

𝑋

𝑑𝑏𝑚 = 𝑋 0 − 𝑋 𝑠𝑣𝑜

𝐽𝑐𝑓𝑏𝑛 = 𝑞0 + 𝑞1𝑋

𝑑𝑏𝑚

𝐹𝑞 − Δ𝐹𝑢𝑏𝑠𝑕𝑓𝑢 𝑓

beam

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

HPGe setup (high resolution, low efficiency)

  • Collimated HPGe detectors
  • 137% detector @ 55°
  • 90% detector @ 90°
  • Lead shielding
  • Copper liners
  • Radon box (N2 flushing)

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

HPGe setup - results

e.g. 189.5 keV resonance Black: on-resonance Turquoise: off-resonance

Discovery of 3 new low-energy resonances Upper limits on 2 tentative resonances New evaluation of TNRR Better description of Na/O anti-correlation in GS  Tentative resonances not completely excluded  Direct capture and broad resonances not addressed

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New high-efficiency setup is required for further infestigation

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

In the meantime…

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TUNL (North Carolina) confirmed the existence of two out of three new resonances observed at LUNA They found slightly larger strengths, probably because of:

  • weak branches
  • angular distribution effects

not detected at LUNA using HPGe detectors

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Federico Ferraro | federico.ferraro@ge.infn.it

BGO setup (low resolution, high efficiency)

BGO detector  4 solid angle coverage 6 segments Low resolution (𝐺𝑋𝐼𝑁 ≅ 500 keV @ 𝐹𝛿 = 9 MeV) High efficiency (65% @ 𝐹𝛿 = 662 keV) Sensitivity to weak decay branches Target chamber 420 mm long connecting tube 40 mm long collimator 108 mm long interaction region Beam calorimeter Calorimeter body Chiller Power supply Acquisition & control system

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

6 segments Independent DAQ List mode acquisition Independent calibration Offline coincidence analysis Single spectra Gated spectrum Addback spectrum

14N(p,)15O

DAQ

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Background

40K 214Bi 208Tl 11B(p,)12C 18O(p,)19F

(n,) events from (,n) reactions

Present in every spectrum, used for energy calibration

Background

  • laboratory (depends on acquisition time only)  scaled and subtracted
  • beam-induced (depends on E, I, contaminants,…)  inert target, scaling to ROImonitor

Black: laboratory background Red: BIB (Ep=156 keV, Ar target)

22Ne(p,)23Na ROI 22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Results

22Ne(p,)23Na cross section measurement at astrophysical energies

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Because of the detector geometry, BGO results are nearly unaffected by

  • target thickness/resonance width (max. effect of 1-2%)
  • angular distribution (max effect of 4%)

New measurements of resonance strengths and branching ratios have been obtained for the resonances at 156.2, 189.5 and 259.7 keV

New resonances at 156.2, 189.5 and 259.7 keV

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Federico Ferraro | federico.ferraro@ge.infn.it

Branching ratios (e.g.: 189.5 keV resonance)

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Results

22Ne(p,)23Na cross section measurement at astrophysical energies

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Tentative resonances Non resonant capture

The simulated decay pattern comes from the nearby 𝐹𝑦 = 8830 keV state, which has the same 𝐾𝜌 = 1

2 +

  • f the suggested resonances at 71 and 105 keV.

New upper limits have been put in 63-78 keV and 95-113 keV energy ranges. Contribution by the 𝐹𝑦 = 8664 keV state ( 𝐾𝜌= 1

2 +

). Astrophysical S-factor and spectroscopic factor 𝑫𝟑𝑻 fitted to match experimental spectrum.

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Federico Ferraro | federico.ferraro@ge.infn.it

Implications on the Thermonuclear reaction rate

22Ne(p,)23Na cross section measurement at astrophysical energies

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For the first time all of the relevant contributions to the TNRR are based on experimental data!

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Federico Ferraro | federico.ferraro@ge.infn.it

collaboration:

  • L. Csedreki, L. Di Paolo, A. Formicola, M. Junker| INFN LNGS, Italy
  • D. Bemmerer, K. Stoeckel, M. Takacs, | HZDR Dresden, Germany
  • C. Broggini, A. Caciolli, R. Depalo, P. Marigo, R. Menegazzo, D. Piatti | Università di Padova and INFN Padova, Italy
  • C. Gustavino | INFN Roma1, Italy

G.F. Ciani, Z. Elekes, Zs. Fülöp, Gy. Gyurky,T. Szucs | MTA-ATOMKI Debrecen, Hungary

  • M. Lugaro | Konkoly Observatory, Hungarian Academy of Sciences, Budapest, Hungary
  • O. Straniero | INAF Osservatorio Astronomico di Collurania, Teramo, Italy
  • P. Corvisiero, F. Ferraro, P. Prati, S. Zavatarelli | Università di Genova and INFN Genova, Italy
  • A. Guglielmetti, E. Masha| Università di Milano and INFN Milano, Italy
  • J. Balibrea, A. Best, A. Di Leva, G. Imbriani, | Università di Napoli and INFN Napoli, Italy
  • F. Cavanna, G. Gervino | Università di Torino and INFN Torino, Italy
  • M. Aliotta, C. Bruno, T. Chillery, T. Davinson | University of Edinburgh, United Kingdom
  • F. Barile, G. D’Erasmo, E.M. Fiore, V. Mossa, F. Pantaleo, V. Paticchio, L. Schiavulli| Università di Bari and INFN Bari
  • R. Perrino | INFN Lecce, Italy

Thank you for your attention!

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Extras

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro on behalf of the LUNA collaboration | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

22Ne(p,)23Na @ LUNA – HPGe phase

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Federico Ferraro | federico.ferraro@ge.infn.it

BBN, pp chain, CNO cycle, and beyond…

22Ne(p,)23Na cross section measurement at astrophysical energies

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BBN reactions network and pp chain CNO cycle NeNa and MgAl cycles The yellow lines highlight two carbon burning reactions that will be studied with LUNA MV:

12C(12C,p)23Na and 12C(12C,α)20Ne

H burning He burning C burning → LUNA-MV

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Federico Ferraro on behalf of the LUNA collaboration | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Na/O anticorrelation (for many different dilution fraction)

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

Revision of HPGe results

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na @

22Ne(p,)23Na cross section measurement at astrophysical energies

3 MV Tandem accelerator Beam current: ~ 10 μA Solid target (implantation @ LNL) 2 HPGe detectors (90° and 55°) Active anti-compton shields (BGO) 2 independent DAQ chains ωγ determined w.r.t. higher energy resonance

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Federico Ferraro | federico.ferraro@ge.infn.it

22Ne(p,)23Na cross section measurement at astrophysical energies

22Ne(p,)23Na @ HZDR

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Federico Ferraro | federico.ferraro@ge.infn.it

Detection efficiency (over beam path)

14N(p,)15O 88Y (1836 keV) interaction chamber

Test of the 6 segments Validation of the simulation (up to high energy)

The target is extended! 22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Calorimeter calibration

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Results on the off-resonance cross section

22Ne(p,)23Na cross section measurement at astrophysical energies

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The S-factor increase at low energy is due to a subthreshold resonance (𝐹𝑦 = 8664 keV) considering BR 84 ± 3 % to GS: 𝐷2𝑇 = 0.42 ± 0.08 𝑇𝐻𝑇

𝐸𝐷 = 13 ± 5 keV b

𝑇𝑢𝑝𝑢

𝐸𝐷 = 50 ± 12 keV b

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Federico Ferraro | federico.ferraro@ge.infn.it

BBN, pp chain, CNO cycle, and beyond…

22Ne(p,)23Na cross section measurement at astrophysical energies

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Federico Ferraro | federico.ferraro@ge.infn.it

Reminder on the nuclear cross section

𝜏 ≅ 𝜏𝑂𝑆 + 𝜏𝑆

𝜏𝑂𝑆 𝐹 = 1 𝐹 𝑓−2𝜌𝜃𝑻 𝑭 𝜏𝑆 𝐹 = 𝜇2 4𝜌 𝝏𝜹 Γ 𝐹 − 𝐹𝑆 2 − Γ/2 2

S-factor Resonance strength Intermediate state

22Ne(p,)23Na cross section measurement at astrophysical energies

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