Jorge Pereira ([email protected]) National Superconducting Cyclotron Laboratory (NSCL/MSU)

Jorge Pereira, INPC 2007

Jorge Pereira

([email protected])

National Superconducting Cyclotron Laboratory (NSCL/MSU)

Joint Institute for Nuclear Astrophysics (JINA)

Studies of r-process nuclei at NSCL Astrophysical importance of -decay studies

in the understanding of the r-process



Synthesis of Heavy Elements

•An overview on astronomical abundance observations

SNR 0103-72.6Credit: NASA/CXC/PSU/S.Park et al.

M57 Ring Nebula.


Observed Solar-System Heavy-Element abundances

log = log10 (Yel/YH)+12

Solar

s-process

p-process

r-process

Different processes contribute to the observed Heavy-Element abundancesr ≈ “leftovers” ( Solar – s )


CS22892-052HD 115444

BD+1703248CS 31082-001

HD221170

J.Cowan and C.Sneden, Nature 440, 1151 (2006)

R-process elemental abundances: Solar-System vs. Metal-Poor Stars (MPS)

Consistent abundances (MPS and Solar) pattern for Z > 47 Very ROBUST r-process (MAIN r-process)

Missing abundance Another process contributing to solarlight r-residuals?


LEPP elemental= HD122563– MainLEPP elemental= solar– s-process– Main

F. Montes et al., submitted to ApJ

LEPP contributes to r-process elemental abundances Very consistent pattern Second ROBUST process

LEPP contributes to r-process elemental abundances Very consistent pattern Second ROBUST process

What about less enriched stars? LEPP process C. Travaglio et al., ApJ 601, 864 (2004)


D. Swesty, A. Calder, E.Wang, D.Bock, NCSA (1998)

•How do these processes operate?

•What is their site?Comparing results (e.g. classical approach) with

observed abundance pattern

•

E0102-72.2


Astrophysical conditions: parameterized studies (e.g nn, T, tirr)…freeze-out, neutrinos

Nuclear Physics (mostly theoretical): -decay properties (T½ , Pn, masses)

What are these models sensitive to? Astrophysics VS. Nuclear Physics

100 120 140 160 180 200 22010-4

10-3

10-2

10-1

100

101

Mass number

ETFSI-QETFSI-1

Classic model. Different Nuclear Physics

C.Freiburghaus et al., ApJ516, 381 (1999)

Astrophysical r-process model calculations are very sensitive to Nuclear Physics of

nuclei involved


Why -decay studies in the search for the r-process and LEPP sites?

•NSCL experiments with Exotic Beams


-decay properties in the r-process

•Pn-values around r-process nuclei: What is the path followed by matter flow after freeze-out (Abundance pattern post freeze-out)

•Half-lives of r-process nuclei:

The clock of the r-process

What are the bottle-necks of matter flow? Abundance pattern

prior freeze-out

•T1/2 and Pn (gross -decay properties):

First insights into shell structure at low energies and above Sn

(Deformation, nucleon-nucleon interaction, new magic numbers, etc…)

-decay studies of very exotic neutron-rich nuclei at NSCL


Ion Source

K500: Operated 1982-1989

Coupled in 2000

K1200: Operated 1989-1999

Exotic beam delivery: The CCF


Ion Source

K500

K1200A1900

Exotic beam delivery: The A1900 in-flight separator


A1900

Im2

Ion Source

K500

K1200


ToF Im2-N3

E PIN

N3 vault

•Separation and identification of exotic beam: ToF vs. E

E P

IN (

a.u

.)

ToF Im2-N3 (a.u.)

107Zr


A1900

Im2

Ion Source

K500

K1200


N3 vault

•Separation and identification of exotic beam: ToF vs. E

•Exotic beam Implantation station (in the N3 vault)


Silicon PIN Stack4 x Si PIN DSSD (

•Implantation DSSD: x-y position (pixel), time

•Decay DSSD: x-y position (pixel), time 6 x SSSD (16) Ge

Implantation station: The Beta Counting System (BCS)

•Veto light particles from A1900

J.J. Prisciandaro et al., NIMA 466, 492 (2001)

105Zr

Fit (mother, daughter, granddaughter, background)

T1/2


Silicon PIN Stack4 x Si PIN DSSD (

•Implantation DSSD: x-y position (pixel), time

•Decay DSSD: x-y position (pixel), time 6 x SSSD (16) Ge•Beta calorimetry

Implantation station: The Beta Counting System (BCS)

•Veto light particles from A1900


Implantation station: The Neutron Emission Ratio Observer (NERO)

Boron Carbide Shielding

Polyethylene Moderator

BF3 Proportional Counters

3He ProportionalCounters

G. Lorusso, J.Pereira et al., PoS NIC-IX (2007)


Implantation station: The Neutron Emission Ratio Observer (NERO)

Nuclei with -decay Nuclei with -decay AND neutron(s)

Pn-values

Measurement of neutron in “delayed” coincidence with -decay


Implantation station: The Segmented Germanium Array (SeGA)

16 SeGA detectors around the BCS Efficiency ~7.5% at 1 MeV

W.Mueller et al., NIMA 466, 492 (2001)


Implantation station: The Segmented Germanium Array (SeGA)

-delayed gamma spectroscopy of daughter


Results from -decay r-process campaigns at NSCL


NSCL r-process campaigns – MSU/Mainz/Notre Dame/Maryland

Known before

NSCL Experiments done• P. Hosmer, P. Santi, H. Schatz et al. • F. Montes, H. Schatz et al.• B. Tomlin, P.Mantica, B.Walters et al.• J.Pereira, K.-L.Kratz, A. Woehr et al.

Critical region78Ni

107Zr

NSCL reach

129Rh


1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

70 120 170 220

Mass (A)

Ab

un

da

nc

e (

A.U

.)

Observed Solar Abundances

Model Calculation: Half-Lives fromMoeller, et al. 97

Same but with present 78Ni Result

Exp. 78Ni T1/2 = 110 ms

Predicted 78Ni T1/2: 460 ms

P. Hosmer et al. PRL 94, 112501 (2005)

+100

-60

I)-decay half-live of 78Ni50 waiting point

Half-live of ONE single waiting-point nucleus:

Speeding up the r-process clock

Increase matter flow through 78Ni bottle-neck

Excess of heavy nuclei (cosmochronometry)


II) “Gross” nuclear structure around 120Rh65 from -decay properties

F. Montes et al., PRC73, 35801 (2006)

Inferring (tentative) nuclear deformations with QRPA model calculations

•Half-lives and Pn-values sensitive to nuclear structure at different energies: (Complementary information to infer nuclear deformation)

•Need microscopic calculations beyond QRPA

•Possible signatures of new shell-structure when approaching r-process path


II)Probing sustainability of N=82 at 120Pd from -delayed -spectroscopy

B.Walters, B.Tomlin et al., PRC70 034414 (2004)

•No evidence of shell-quenching when approaching waiting point 128Pd at N=74

•Need more E(2+) data at 74<N<82


III) -decay properties of Zr isotopes beyond mid-shell N=66

•A ≈110: Calculations fail to reproduce r-process abundance pattern below A=130 peak

•N~66 is at mid-shell: Shape transitions between sudden onset of deformation at N=60 and closed shell at N=82

•Possible double-magic Z=40, N=70: Effects from spherical shape of 110Zr70 observable at 66<N<70? J. Dowaczewski et al.,PRL72, 981 (1994) 10

100

1000

10000

62 63 64 65 66 67 68

N

Ha

lf-l

ife

(m

s)

Zr literature

Zr preliminary

QRPA Def.

QRPA Spher.

J.Pereira et al., in preparation

•Shorter half-life of (potential) waiting-point 107Zr67 may

affect predicted r-process abundances at A~110

•QRPA consistent with spherical shapes beyond mid-shell (possible signatures of double magic N=40 N=70?)

•Urgent need of microscopic calculations beyond QRPA


Almost all -decay half-lives of r-process nuclei at N=82 and N=126 will be reachable with ISF

pps

Reach for future r-process experiments with new facilities (ISF, FAIR, RIBF…)

Fine!…but what do we do meanwhile?

a) Keep observing abundances and wait for these facilities…

b) Continue r-process studies with theoretically calculated -decay properties (to be confirmed with new measurements)


Conclusions

•Despite many years of intensive effort, the r-process site continues to be one of the BIG SCIENCE QUESTIONS for the new century – NAS REPORT. New LEPP process complicates the situation

•Besides being direct r-process inputs, beta-decay properties of exotic nuclei turned out to be an effective probe for nuclear structure studies of exotic nuclei

•R-process experimental campaigns at NSCL provide an extensive data body of beta-decay properties of r-process nuclei. Comparisons with calculations microscopic models will improve astrophysical r-process calculations

•New facilities will largely extend the r-process regions accessible. Meanwhile, new observations (SEGUE) and new measurements of exotic n-rich nuclei are highly necessary


Thanks to:

•NSCL/MSU: Hendrik Schatz, Paul Mantica Ana Becerril, Tom Elliot, Alfredo Estrade, Ron Fox, Daniel Galaviz, Tom Ginter, Mark Hausmann, Paul Hosmer, Linda Kern, Giuseppe Lorusso, Milan Matoš, Fernando Montes

•Univ. Notre Dame: Andreas Woehr Ani Aprahamian, Matt Quinn

•Mainz Universität: Karl-Ludwig Kratz Oliver Arnd, Ruben Kessler, Stefan Hennrich, Bernd Pfeiffer, Florian Schertz

•University of Maryland: William Walters

•JINA and VISTAR collaborations


Backup Slides


The Big Question

What is the origin of heavy elements

from iron to uranium ?

One of the “Eleven Science Questions for the New Century” (NAS report “Connecting Quarks with the Cosmos”)

Do we understand the observed heavy-element abundances ?


What about less enriched stars? (Leftover of Leftover)

Similar observations for Sr, Zr by C.Travaglio et al. Light Element Primary Process (LEPP)

– C. Travaglio et al., ApJ 601, 864 (2004) –

Some stars (e.g. HD122563) show enrichment of lighter elements (Sr-Ag) compared to MAIN r-process

– F.Montes et al., submitted to ApJ –


[Eu/Fe] Enrichment with main r-process

Light r / Heavy r (Eu) Heavy r / Heavy r (Eu)

What about less MAIN r-process enriched stars?

Consistent with second process producing also Sr-Ag LEPP, identified by Travaglio et al. 2004

Montes et al. to be published

Solar r

Slope indicatesratio of light/heavy)changes for lessenriched stars

Some stars havelight r-elementsat solar level

Heay r-patternrobust andagrees with solar

Light r-elementsat high enrichmentfairly robust andsubsolar

[Y/Eu] [La/Eu]

[Ag/Eu] [Sm/Eu]

[Eu/Fe] [Eu/Fe]


Trying to fit LEPP pattern with n-capture flow

Low nn and high nn fit low ZLow nn also fits small high Z abundances


Simmerer (Cowan et al.) /Lodders

-2.50

-2.00

-1.50

-1.00

-0.50

30 40 50 60 70 80 90

Element number

log

Travaglio/Lodders

-2.50

-2.00

-1.50

-1.00

-0.50

30 40 50 60 70 80 90

Element number

log

Conclusions depend on s-process

s-process from Simmerer et al. (Cowan et al.) s-process from Travaglio et al.

Need reliable s-process (models and nuclear data)Clearly something is going on for Z < ~50 (“light” p-process elements)

Need reliable s-process (models and nuclear data)Clearly something is going on for Z < ~50 (“light” p-process elements)

Need to look at many stars …


Astrophysical conditions: parameterized studies (e.g nn, T, tirr)

Nuclear Physics (mostly theoretical): -decay properties (T½ , Pn), masses

• Freeze-out • Neutrino presence

• n-capture rates• Fission barriers

What are these models sensitive to? Astrophysics VS. Nuclear Physics

100 120 140 160 180 200 22010-4

10-3

10-2

10-1

100

101

Mass number

ETFSI-QETFSI-1

Classic model. Different Nuclear Physics

C.Freiburghaus et al., ApJ516, 381 (1999)

10

10

10

10

10

10

Hot bubbleClassic model

Mass number

Ab

un

dan

ces

(Si≡

106)

Same Nuclear Physics

Astrophysical r-process model calculations are very sensitive to Nuclear Physics of

nuclei involved


Waiting point approximationDefinition: ASSUME (n,)-(,n) equilibrium within isotopic chain

This is a valid assumption during most of the r-process

BUT: freezeout is neglected

Freiburghaus et al. ApJ 516 (2999) 381 showed agreement with dynamical models

How good is the approximation ?

Consequences

During (n,)-(,n) equilibrium abundances within an isotopic chain are given by:

• Time independent • Can treat whole chain as a single nucleus in network• Only slow beta decays need to be calculated dynamically

• Neutron capture rate independent (During most of the r-process n-capture rates do not matter !)

)/exp(21

),(2

)1,(

),(

)1,(2/32

kTSkTmA

A

AZG

AZGn

AZY

AZYn

un


Inferring r-process conditions from “site-independent” models

•Parameterized Astrophysical conditions (e.g. nn, T, tirr)

Conditions which fit the A≈80 and A ≈ 130 r-process abundance peaks

K.-L. Kratz et al., ApJ 403, 216 (1993)


Conditions for the r-process from “site-independent” models

•Parameterized Astrophysical conditions (e.g. nn, T, tirr)•Nuclear Physics of nuclei involved (mostly theoretical)

K.-L. Kratz et al., ApJ 403, 216 (1993)

Conditions which fit the A≈80 and A ≈ 130 r-process abundance peaks different

components with large nn, T

BUT very sensitive to Nuclear Physics!!!

100 120 140 160 180 200 22010-4

10-3

10-2

10-1

100

101

Mass number

ETFSI-QETFSI-1

Classic model with different Nuclear Physics

C.Freiburghaus et al., ApJ 516, 381 (1999)


n/seed is higher for• lower Ye

(more neutrons)

• higher entropy (low density low 3-rate slow seed assembly)

• faster expansion (less time to assemble seeds)

1) high S, moderate Ye

2) low S, low Ye

2 possible scenarios:

(Meyer & Brown ApJS112(1997)199)

Neutron to seed ratios


Experiments with implanted RNB

Production of Primary Beam: Coupled Cyclotron Facility, CCF

Production of RNB: A1900 in-flight separator (Fragmentation reactions…and Fission (in progress))

-decay r-process motivated experiments at NSCL

Beta Counting System: Half-lives (T1/2)

•NERO:-delayed n-emission probabilities (Pn)

•SeGA:-delayed and “direct” -spectroscopy


Results from earlier experiment in Ni

I)-decay half-live of 78Ni waiting-point: testing model calculations

Half-lives and Pn-values sensitive to nuclear structure at different energies: complementary

information to rule out models


Results: -decay Half-lives (even with low statistics)

Decay-curves fits (mother, daughter, granddaughter)

105Zr107Zr106Zr

MLH: Find maximum of Likelihood function (sum of join probability density for 1, 2 and 3-member decay chains)

)()3()()2()()1()( 13221111123123 pnpnpnL iiiNi

0

0.2

0.4

0.6

0.8

1

1.2

0.5 0.7 0.9 1.1 1.3 1.5

Half-live (sec)

Lh

F

P1

P2

P3

LhF

0

0.2

0.4

0.6

0.8

1

1.2

0 0.2 0.4 0.6 0.8 1

Half-live (sec)

Lh

F

P1

P2

P3

LhF

104Zr 107Zr


Calculated -decay properties of r-process nuclei with FRDM-QRPA

Macro/Microscopic model global applicability (better suited for r-process models)

1. Calculation of ground-state masses and deformation parameters FRDM + Strutinsky microscopic corrections (Shell + Pairing)

2. Use deformation parameters to determine single-particle levels (folded-Yukawa + Lipkin-Nogami)

3. Calculate Gamow-Teller -strength function using calculated

and adding residual interaction VGT=2GT:1- • 1+: with operator 1± =∑i ( t±)i

Sensitivity to Deformation, Level ordering, Masses

P. Möller et al., NPA 1992; ADNDT 1995, 1997; PRC2000


Future Facility Reach(here ISF)

NSCL r-process campaign – MSU/Mainz/Notre Dame/Maryland

Known before

NSCL Experiments done• P. Hosmer, P. Santi, H. Schatz et al. • F. Montes, H. Schatz et al.• J.Pereira, K.-L.Kratz, A. Woehr et al.

Critical region

NSCL reach

78Ni

107Zr


•Initial conditions: =29mg/cm3; T=1.5GK; n/seed = 92

The r-process abundances (observed in Solar System and Metal-Poor Stars)

is the only clue that “he” left behind…for us


Nuclear Physics in the r-process

Nuclear IngredientDirect Astrophysical

interestIndirect Astrophysical

interest

Production cross-sections from different reaction mechanisms

Production of r-process nuclei to be investigated

-decay half-lives (T1/2)

-delayed neutron-emission probabilities (Pn)

r-process time scale (T1/2)

Abundance pattern prior (T1/2) and post freeze-out (Pn)

Nuclear structure information (at “low” cost)

Nuclear masses (neutron separation energies)

r-process path Nuclear structure

Gamma spectroscopyDetailed nuclear structure information (shell-quenching)

Fission barriers Fragment mass distributions

Primordial abundance pattern (Fission Cycling)Final abundance pattern (-delayed, -induced fission);Endpoint

What Nuclear Physics ingredients are really important?


(Pearson, et al. 1996)

r-process studies in two different regions of Terra Incognita

Two r-process regions were explored:Ge-Br (56≤N≤60): lies in the region prior to the “weak” r-process. It could also constitute part of the seed r-process nuclei

Y-Mo (A ≈110): lies right before the abundance trough prior to the A=130 peak

C.Freiburghaus et al., ApJ516 (1999) 381

100 120 140 160 180 200 22010-4

10-3

10-2

10-1

100

101

Mass number

ETFSI-Q

ETFSI-1

A=110

Z number


Nuclear Structure motivation

•What do we want to measure? -decay half-lives and Pn-values

•Why?

•They provide insight into nuclear structure in two “critical” r-process regions

• Direct inputs in r-process calculations

Evolution of nuclear shape in two regions of Terra Incognita •Ge-Br (56≤N≤60): does the sudden onset of deformation (at N=60) persist “south” of 96Kr?

•Y-Mo (A ≈110): are there more shape transitions between sudden onset of deformation at N=60 and closed shell at N=82 (new sub-shells?)

Nuclear shape evolution in these two regions will affect substantially the calculated masses and-decay processes: strong impact in r-process

calculated abundances

R.F. Casten, Nucl. Phys. A443 (1985) 1

N. Schunck et al., Phys. Rev. C63 (2004) 061305(R)


Gross -decay properties used as nuclear structure probes

Gross -decay properties are sensitive to nuclear structure at different energy regimes

5β EQf

βQ

0

ββ1/2 dEE)QR,f(Z,(E)ST

Low energies

β

n

Q

S

ββ1/2n dEE)QR,f(Z,(E)STP

Energies above Sn

Dobaczewski et al., PRL72 (1994) 981

B. Pfeiffer et al., NPA693 (2001) 282


Sensitivity of QRPA to Mass and Deformation


Preparation of experiments

Nuclei produced by Fragmentation of 136Xe on Be

•Beta Counting System (CS): T1/2

•Neutron Emission Ratio Observer (NERO): Pn

•Special blocking system (Slits + Finger) at Im1 to stop primary-beam charge-state

•BCS and NERO upgrades: VME-based DAQ, migration to production DAQ software (~400 channels), new Ge crystal (tested to be used for particle ID, -spectroscopy)

•Special setup for particle ID based on known sec-isomers with SeGA globes


Secondary Beam

Experimental Setup

Particle ID Setup (SeGA)

Production Setup (BCS+NERO)

•Isomers (sec) implanted in Al degrader

•Emitted gammas detected with 3 SeGA detectors (6%)

4 Si PIN: E, trigger

1 DSSD (1600 pixels): •4 cm x 4 cm active area•1 mm thick•40-strip pitch in x and y dimensions (1600 pixels)

1 SSSD (16 strips): Veto

BCS (Beta Counting System) NERO (Neutron Emission Ratio Observer)

Boron Carbide Shielding

Polyethylene Moderator

BF3 Proportional Counters

3He ProportionalCounters

•Fragments implanted in DSSD

•Emitted (DSSD)

•Delayed neutrons (NERO)



Conquers of Terra Incognita in r-process campaigns at NSCL

r process

N=126

N=82

Z=50

Z=82

N=50

Z=28

F.Montes, H.Schatz, T 1/2,, Pn

B.Tomlin, B.Walters, P.Mantica, T1/2, -spectroscopy

J.Pereira, A.Woehr, H.Schatz T 1/2,, Pn

J.Pereira, K.-L. Kratz, T 1/2,, Pn

P.Hosmer, H.Schatz, T 1/2,, Pn

M.Matoš, A.Estrade, Masses (ToF technique)

Mass knownHalf-life knownTerra Incognita


How about future?•What can be done at NSCL for the r-process?



How to reach now new territories at NSCL for r-process studies

Mass knownHalf-life knownTerra Incognita

r process

N=126

N=82

Z=50

Z=82

N=50

Z=28

Fission of 238U at NSCL

• Optimistic results from test (May 2006)

• Beam test development (August 2006)

1. Future experiment to explore region around 128Pd

2. Gain factor 10-100 with respect to Fragmentation of 136Xe

3. Possibility to study E(21+), E(41+) isotopic evolution of nuclei near 132Sn (BCS + SeGA)

4. Possibility to measure masses of waiting-point nuclei e.g. 130Cd with ToF-Btechnique (A1900+S800)

If successful it will allow to go one step farther into Terra Incognita New r-process

regions to be explored at NSCL


Some advances of what it is coming in the near Future for the r-process

•RF-kicker Fragment Separator:.Purify beam-cocktail. Reduce background due to implanted contaminants in the BCS

•Development of U beams: Extend -decay studies and mass measurements to new r-process regions

•Digital Data Acquisition (DDAQ): Increase SeGA resolutions and efficiencies (tests in progress) and BCS efficiencies (to be implemented). Precise -decay half-lives, Q values and spectroscopy information of new r-process

•LEBIT: Development of gas stopper for future use with reaccelerated beams. Measurement of important reactions occurring in the -process (seed nuclei for the r-process)

•BCS calorimeter: Measurement of Q values for r-process nuclei (additional structure information)


…and in the Future: NSCL upgrade

NSCL upgrade will open new possibilities in Nuclear Astrophysics

MSU Upgrade Beam intensities (pps)

pps

•Fast beams: A very significant fraction of r-process nuclei will be reached experimentally.

•Integral -decay properties of every r-process waiting-point below A=130 peak (included) and around N=126.

•Spectroscopy studies of waiting-point nuclei at N=82 and N=126: solution of the shell-quenching puzzle.

•Masses of very exotic nuclei: better determination of r-process path (Sn≈2MeV).

•Reaccelerated beams: Direct measurements of important reactions involved in the -process (generation of r-process seed nuclei): (nn,)9Be (di-neutron channel), (n,)9Be, (t,)7Li, 7Li(n,)8Li, 8Li(,n)11B…

•Other Nuclear Astrophysics aspects.

•Majority of reaction rates in rp-process will be within reach with indirect methods. Direct measurements will be achievable up to A<60.

•Measurement of GT-strength for e-capture by all relevant unstable nuclei in SNeI,II will be possible via charge exchange reactions.

•Very important reaction rates: e.g. 12C(,)16O


Epilogue


Summary

•Despite many years of active investigation the site of the r-process is still unknown. Nuclear Physics is crucial to solve this mystery

•My main research on the r-process included studies of reaction mechanisms to produce neutron-rich and -decay studies of r-process nuclei:

•GSI: experimental studies of neutron-rich nuclei approaching the r-process region around N=126

•GSI: -decay properties of waiting-point 137Sb abundance spikes around A=130 peak

•NSCL: analysis of nuclear structure of r-process nuclei based on -decay studies abundance pattern around the weak r-process region and the A=110 abundance trough region

•Future developments at NSCL (including upgrade) will open new opportunities to extend our knowledge of the r-process

•NSCL will become the “r-process facility” and one of the dominant laboratories in Nuclear Astrophysics


• Convince someone to cover the expenses of our adventure

• Develop new tools to reach “Terra Incognita”

• Learn from the natives living in the new territories

The recipe to explore “Terra Incognita”

The conquer of Terra Incognita (or the New World)

…so that finally, Terra Incognita will not be “Incognita” anymore


Acknowledgements

•NSCL/MSU: Hendrik Schatz, Paul Mantica Ana Becerril, Tom Elliot, Alfredo Estrade, Ron Fox, Daniel Galaviz, Tom Ginter, Mark Hausmann, Vladimir Henzl, Daniela Henzlova, Paul Hosmer, Linda Kern, Giuseppe Lorusso, Milan Matoš, Fernando Montes, Josh Stoker, Andreas Stoltz, Oleg Tarasov, Remco Zegers

•Univ. Notre Dame: Ani Aprahamian, Andreas Woehr, Matt Quinn

•Univ. Santiago de Compostela: Jose Benlliure, Teresa Kurtukian

•Mainz Univ.: Karl-Ludwig Kratz Oliver Arnd, Ruben Kessler, Stefan Hennrich, Bernd Pfeiffer, Florian Schertz

•GSI colaboration: Peter Armbruster, Monique Bernas, Aleksandra Kelic, Valentina Ricciardi, Karl-Heinz Schmidt

•JINA and VISTAR collaborations


Backup Slides


OUTLOOK

•Introduction: what is the r-process? What do we need to know to learn about “him”?

•My relationship with the r-process:•When we first met (at GSI): approaching Terra Incognita towards N=126 shell

•Learning more about r-process at GSI: studies around waiting point 137Sb

•R-process experiments at NSCL: incursion into Terra Incognita through two different fronts

•Discovering what NSCL can do for the r-process

•What can we do for “them”? Future perspectives



Present NSCL astrophysical motivated projects

Group Project Project Project

Astrophysics

(H.Schatz)

-decay

(r-process)

Masses

(r-process)p-resonances (rp-process)

HIRA

(B.Linch)

Masses

(rp-process)

2p-correlations

Isospin-EOS

(Neutron Stars)

LEBIT

(G.Bollen, D.Morrisey)

Masses

(rp-process)

Gas cell stopper

(Reaccelerated beams)

S800

(R.Zeger)

(CE-reactions

SNeI, II)



An overview of the present situation of Nuclear Astrophysics at NSCL

Group / People ProjectsSenior researchers

(Faculty/Staff)Post-docs Graduates Undergraduates

Astrophysics

(H.Schatz)4 3 5 3

HIRA

(B.Linch)2 2 2 4 0

S800

(R.Zenger, S.Austin)

3 2 2 0 0

Beta

(P.Mantica)1 1 1 1 0

4 Groups 8 Post-docs

10 Exp. Projects 10 Graduates

6 Faculty/Staff 3 Undergraduates

Clearly NSCL is a natural facility to cover an extensive range of different topics in Nuclear Astrophysics

Jorge Pereira ([email protected]) National Superconducting Cyclotron Laboratory (NSCL/MSU)

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Transcript of Jorge Pereira ([email protected]) National Superconducting Cyclotron Laboratory (NSCL/MSU)