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Alchemy of the Universe The Nucleosynthesis of Chemical ElementsDr. Adriana Banu, James Madison UniversityJanuary 22, Saturday Morning Physics111Big questionsBut what produces it in the Sun? Gravity (which governs planets motion)?! Chemical reactions like on Earth (fuel burning, explosions...)?! In the 1930s we got the answer: nuclear reactions! Namely fusion! What about the other stars?!We knew for long time that our energy comes from Sun! 2. How were/are the chemical elements created? (nucleosynthesis) The answer is still: nuclear reactions! But which reactions?! How they proceed?!3. Did nucleosynthesis stop, or continues today? 2If in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words?Everything is made of atoms.

If you want to make an apple pie from scratch, you must first create the universeWe are star-stuff Richard Feynman- Carl Sagan

Nobel Prize in Physics, 19653From Aristotle to MendeleyevIn search of the building blocks of the universeGreek philosophers4 building blocks18th-19th century Lavoisier, Dalton, distinction between compounds and pure elements

atomic theory revived 1896 Mendeleyev 92 building blocks(chemical elements)

earthwaterairfire

Periodic Table of Elements4La Mendeleev nu erau 92. 92 sunt naturale, s-a ajuns la 118

THE ATOMTHE NUCLEUSelectronsnot to scale5Atom = nucleus + electrons(10-10 m)+Ze

-eNucleus = protons + neutrons(10-14 m)electronS6Modern Alchemy: radioactivity emission of radiation from atoms 3 types observed: , and

1896 Becquerel discovers radioactivity

A. H. BecquerelPierre CurieMarie Curie

The Nobel Prize in Physics 1903

(Helium)transmutation7Chart of the NuclidesA chemical element (X) is uniquely identified by the atomic number Z !XAZNNuclides that have the same Z but different N are called isotopes !Mass number: A = N + Z

Z~ 3000 currently known nuclides~ 270 stables only !~ 7000 expected to existColor Key:Stable+ emission- emission particle emissionSpontaneous fission

N118Sn5068118Sn50118Sn8Oxygen (65%) Carbon (18%) Hydrogen (10%) Nitrogen (3%) Calcium (1.5%) Phosphorus (1.0%) Potassium (0.35%) Sulfur (0.25%) Sodium (0.15%) Magnesium (0.05%) BUT ALSOCopper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%)Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts) CHEMICAL ELEMENTS IN YOUR BODYBY WEIGHT9

Nuclear Masses and Binding EnergyThe binding energy is the energy required to dissasemble a nucleus into protons and neutrons.It is due to the strong nuclear force!mp = proton mass, mn = neutron mass, m(Z,N) = mass of nucleus with Z protons and N neutrons),(BENmZmNZMnp-+=10Thanks to E=mc2, tiny amounts of mass convert into huge energy release1 kg of radium would be converted into 0.999977 kg of radon and alpha particles.

The loss in mass is only 0.000023 kg = 23 mg!

Energy = mc2 = mass x (speed of light)2 = 0.000023 x (3 x 108)2 = 2.07 x 1012 joules.Equivalent to the energy from over 400 tonnes of TNT!!!

Radium-226(88 protons + 138 neutrons)Radon-222(86 protons + 136 neutrons)He-4(2 protons + 2 neutrons)1 kg Ra (nuclear) 4*105 kg TNT (chemical)

238Pu11Modern Alchemy:nuclear fusion and fission

The process through which a largenucleus is split into smaller nuclei iscalled fission.

Fusion is the opposite!Fission and fusion are a form ofelemental transmutation becausethe resulting fragments are not the same element as the originalnuclei. Nuclear fusion occurs naturally in stars !12Nuclear ReactionsX + Y A + BA1Z1A2Z2A3Z3A4Z4Conservation laws:A1 + A2 = A3 + A4

Z1 + Z2 = Z3 + Z4Amount of energy liberated in a nuclear reaction (Q-value):Qval = [(m1 + m2) (m3 + m4)]c2 Qval > 0: exothermic process (release of energy) Qval < 0: endothermic process (absorption of energy)initialfinal(mass numbers)(atomic numbers)in starsdefinition13Stability and Binding Energy Curve

Qval >0fusionQval 0fission14What Is the Origin of the Elements?

15all elements formed from protons and neutrons sequence of n-captures and decayssoon after the Big Bang(full) Big-Bang nucleosynthesisAlpher, Bethe & Gamow ( )Phys. Rev. 73 (1948) 803

Burbidge, Burbidge, Fowler & Hoyle (B2FH)Rev. Mod. Phys. 29 (1957) 547 Stellar nucleosynthesiselements synthesised inside the starsnuclear processeswell defined stages of stellar evolution

The Nobel Prize in Physics 1967The Nobel Prize in Physics 1983Two original proposals:Which one is correct?

Nucleosynthesis: the synthesis of Elements through Nuclear Reactions16

BBNBig Bang Nucleosynthesis

occurred within the first 3 minutes of the Universe after the primordial quark-gluon plasma froze out to form neutrons and protons BBN stopped by further expansion and cooling (temperature and density fell below those required for nuclear fusion) BBN explains correctly the observed mass abundances of 1H (75%), 4He (23%), 2H (0.003%),3He (0.004%), trace amounts (10-10%) of Li and Be, and no other heavy elements Mass stability gap atA=5 and A=8 !!!

A = 8A = 5No way to bridge thegap through sequenceof neutron captures during BB 17Using nucl phys knowledge, the correct amounts of primordial isotopes could be explained! Huge success, confirmation of BB scenario!After that, very little happened in nucleosynthesis for a long time.

It required galaxy and star formation via gravitation to advance the synthesis of heavier elements.

Because in stars the reactions involve mainly charged particles, stellar nucleosynthesis is a slow process.temperature and density too small !!! matter coalesces to higher temperature and density18Stellar life cycle

thermonuclear reactions

BIRTHgravitational contractionDEATHexplosionelementmixingInterstellar gasStars energy production stability against collapse synthesis of metals+metals

19Hydrogen Burning slow or fast (explosive) H-burning almost 95% of all stars spend their lives burning the H in their core (including our Sun). Our Sun is a slow nuclear reactor (a fusion reactor we could not make!)

OUR SUN~16,000,000 DEGREES

20Add as first line:Slow or fast (explosive) H-burning our Sun is a slow nuclear reactor (a fusion reactor we cannot have on Earth yet!)

until hydrogen fuel is depleted the life time of our sun depends on the nuclear reaction rateslife time of stars depends on their mass: at larger masses burn faster! We are lucky!Add here : life time of stars depend on their mass: at larger masses burn faster! We are lucky!21Helium Burning: Carbon formation BBN produced no elements heavier than Li due to the absence of a stable nucleus with 8 nucleons

in stars 12C formation set the stage for the entire nucleosynthesis of heavy elementsHow is Carbon synthesized in stars? T ~ 6*108 K and ~ 2*105 gcm-34He + 4He 8Be8Be unstable ( ~ 10-16 s)8Be + 4He 12C22Helium Burning: Oxygen formation12C + 4He 16O + Carbon consumption !Reaction rate is very small not all C is burned, butOxygen production is possible and Carbon-based life became possible Oxygen production from carbon: 23Nucleosynthesis up to Iron

A massive star near the end of its lifetime has onion ring structureCarbon burningT ~ 6*108 K ~ 2*105 gcm-3Neon burningT ~ 1.2*109 K ~ 4*106 gcm-3Oxygen burningT ~ 1.5*109 K ~ 107 gcm-3Silicon burningT ~ 3*109 K ~ 108 gcm-3major ash: Festars can no longer convert mass intoenergy via nuclear fusion !12C +12C -> 20Ne + 4He + 4.6 MeV 23Na + 1H + 2.2 MeV20Ne + -> 16O + 4He20Ne + 4He -> 24Mg + 16O + 16O -> 28Si + 4He + 10 MeV 31P + 1H + 7.7 MeV24Nucleosynthesis beyond IronWE BELIEVE THAT HALF of THE ELEMENTS BEYOND IRON ARE PRODUCEDIN EXPLOSIONS of SUCH STARSSUPERNOVAE25

23 February 198726

27We Saw Supernova 1987A on 23 February 1987. It Actually Happened 168,000 Light Years Ago It was 987,000,000,000,000,000 MILES Away !

987 QUADRILLION MILES28Abundance of the Elements

Features: 12 orders-of-magnitude span H ~ 75% He ~ 23% C U ~ 2% (metals)Almost 5 billion years ago, our solar system began the journeywith its gravitation collapse

If we look around us today, we can see what elementswere in our interstellar cloud29Abundance of the Elements

Features: 12 orders-of-magnitude span H ~ 75% He ~ 23% C U ~ 2% (metals)AuData sources:

Earth, Moon, meteorites, stellar (Sun) spectra, cosmic rays...FeAbundance of elements and isotopes are UNIQUE finger prints of various cosmic processes. To interpret and understand them, diverse and vast nuclear physics knowledge is needed!!! Not fully solved!30U.S. Nuclear Science[Today and for the Next Decade]General goal:

Explain the origin, evolution, and structure of the visible matter of the universethe matter that makes up stars, planets, and human life itself. 31The Science Physics of Nuclei and Nuclear AstrophysicsWhat is the nature of the nuclear force that binds protons and neutrons into stable nuclei and rare isotopes?

What is the origin of simple patterns in complex nuclei?

What is the nature of neutron stars and dense nuclear matter? What is the origin of the elements in the cosmos?

What are the nuclear reactions that drive stars and stellar explosions? 32Nuclear Physics for Astrophysicsexperiments in laboratory to learn about nuclear reaction in stars

Measurement at lab energiesComparison with (reaction) calculationsExtract (nuclear structure) informationCalculate nuclear reaction probabilityCompare with direct measurementsTwo big problems in nuclear astrophysics:- reactions in stars involve(d) radioactive nuclei use RNB- very small energies and very small cross sections indirect methods33Pune aici, micsoreaza toata imaginea si pune 2-3 randuri sus de tot.Experiments in laboratory to learn about nucl reactio in stars:Direct measurements - at very low energies, are very problematic indirect measurements (methods) at larger energies, using RIB (this is what I am doing!)My research highlights34Astrophysical motivation

First starsThe first sources of light: Population III starsabout 400 million yrs.35Fate of Massive Pop III Stars3a

HGpp-I,II,III

HGCNO, rp

GCollapse

Black HoleExplode

dynamic instabilityTc 5 107 Kcrit 0.02 gcm-336Interest in 12N(p,)13OM. Wiescher et al., 1989, Ap.J., 343 :Hot pp chains and rap-process chains in low-metallicity objectspp-I: p(p,e+)d(p,)3He(3He,2p)4Hepp-II: 7Be(e-,)7Li(p,)4Hepp-III: 7Be(p,)8B(+)8Be()4He

pp-IV: 7Be(p,)8B(p,)9C(+)9B(p)8Be()4Hepp-V: 7Be(,)11C(+)11B(p,2)4Herap-I: 7Be(p,)8B(p,)9C(,p)12N(p,)13O(+)13N(p,)14Orap-II: 7Be(,)11C(p,)12N(p,)13O(+)13N)p,)14Orap-III: 7Be(,)11C(p,)12N(+)12C(p,)13N(p,)14Orap-IV: 7Be(,)11C(,p)14N(p,)15O process material from pp cycles into CNO nuclei37

12C12NMelamine target(Faraday Cup)DE-det. (PSSD)Er-det.

12C12NMelamine target(Faraday Cup)DE-det. (PSSD).Experimental Setup for 12N(p,)13O study via (12N,13O) proton transfer reaction

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My research @ Madison Radiation Laboratory (JMU) astrophysical motivation: nucleosynthesis of heavy proton-rich elements beyond iron by photoactivation technique using an electron linear acceleratorMeasurements of photoneutron reactions induced by activation of a target (stable nucleus), i. e. (,n) reaction ratesMedical linacHigh-resolutionGermanium detectors39

LENA/TUNLHIS/TUNLRESOURCES:

Existing facilities for research in Nuclear Astrophysics (North America)

TAMUMichigan State University/NSCLOak Ridge National Laboratory/HRIBFArgonne National Laboratory/ATLASLawrence Livermore National Laboratory/NIFTRIUMF/ISAC (Canada)University of Notre Dame/KN Van de Graaf acceleratorYale University/WNSLFlorida State University/Super-FN tandem/RESOLUT40

Overview of main astrophysical processes41Present and Future Direction in Physics of Nuclei and Nuclear Astrophysics Rare Isotope Beams42Producing radioactive nucleiProtons

RADIOACTIVE NUCLEINeutronsActually, made by nuclear reactions with stable nuclei: Long lived to very short lived isotopes can be produced and used to produce secondary reactions in laboratory43Add here: by nuclear reactions with stable nuclei: Long lived to very short lived isotopes can be produced and used to produce secondary reactions in laboratoryRIB Facilities(Operating or Under Construction)

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FRIB-facility for rare isotope beamsIons of all elements from protons to uranium acceleratedWhere you could work (after 2018)45Where you could work (after 2018)

neutronsprotonsp processWhat is the origin of the elements in the cosmos?s processStellar burningBig Bangr processsite unknown!NAS report: ConnectingQuarks with the cosmos11 questions for the 21st century how where the elements from iron to uranium made?FRIB reach46In summary

47Pune un slide cu JMRad Lab: o schema cu un accel de e-, care dau game, care fac reactiii care produc activare, tu si EI o masurati, etc, motivata de p-nucleiMessages to take awayNuclear reactions play a crucial role in the Universe: they provide the energy in stars including that of the Sun. they produced all the elements we depend on. nucleosynthesis is on-going process in our galaxyThere are ~270 stable nuclei in the Universe. By studying reactions between them we have produced ~3000 more (unstable) nuclei.There are ~4000 more (unstable) nuclei which we know nothing about and which will hold many surprises and applications. Present techniques are unable to produce them in sufficient quantities. It will be the next generation of accelerators and the next generation of scientists (why not some of you?!) which will complete the work of this exciting research field.48

Just As Your Parents Told YouYou Really Are Star Material !49