Direct Measurement of the 21 Na(p, γ ) 22 Mg Reaction: Resonance Strengths and γ - γ Analysis

TRIUMFCanada’s national laboratory for nuclear and particle physics

Direct Measurement of the Direct Measurement of the 2121Na(p,Na(p,γγ))2222Mg Reaction: Mg Reaction:

Resonance Strengths and Resonance Strengths and γγ--γγ AnalysisAnalysis

Mike Trinczek for the DRAGON CollaborationMike Trinczek for the DRAGON Collaboration

TRIUMFTRIUMF

Eighth International Symposium on Nuclei in the CosmosEighth International Symposium on Nuclei in the Cosmos

23 July 200423 July 2004

23 July 2004

NIC8 – Direct measurement of the 21Na(p,γ)22Mg reaction: Resonance strengths and γ-γ analysis

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OutlineOutline

• DRAGON FacilityDRAGON Facility• 2121Na(p,Na(p,γγ))2222Mg resultsMg results• Current and Future workCurrent and Future work

– γγ--γγ Analysis of Analysis of 2222Mg LevelsMg Levels– 2626Al(p,Al(p,γγ))2727SiSi

• SummarySummary

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ISAC: Highest yields for On-Line Facilities, can go up to 100 μA @ 500 MeV DC proton

Target-Ion Sources:Target-Ion Sources:• Surface Surface

– Li, K, Na, Rb, Al, …

• ECR, on-line tests and first experiment

– 18,19Ne

• Laser, off-line test – Ga in the Fall, Al

• Negative, off-line test • FEBIAD prototype • High-power target

tested off-line – 11Li in Oct. 2004

• Actinide target task force

– Tests in early 2005

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DRAGON FacilityDRAGON Facility

D. Hutcheon et al., NIM A 498, 190 (2003).

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DRAGON ProgrammeDRAGON Programme

• Almost completedAlmost completed– 2121Na(p,Na(p,γγ))2222MgMg

• In progressIn progress– 2626Al(p,Al(p,γγ))2727SiSi– 1212C(C(αα,,γγ))1616OO– 1212C(C(1212C,C,γγ))2424MgMg

• Future workFuture work– 26m26mAl(p,Al(p,γγ))2727SiSi– 2525Al(p,Al(p,γγ))2626SiSi

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2121Na(p,Na(p,γγ))2222Mg ReactionMg Reaction

S. Bishop et al., PRL 90, 162501 (2003).

• First direct radioactive beam First direct radioactive beam measurement of the reaction rate, measurement of the reaction rate, populating the 5.714 MeV level in populating the 5.714 MeV level in 2222MgMg

• Measured resonance energy and Measured resonance energy and the resonance strengththe resonance strength– EEcmcm = 205.7 = 205.7 ± 0.5 keV± 0.5 keV

– ωγωγ = 1.03 = 1.03 ± 0.21 meV± 0.21 meV

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Contributions to the Reaction RateContributions to the Reaction Rate

• Extended the measurements Extended the measurements to other states, deduced their to other states, deduced their contributions to the reaction contributions to the reaction rate and their impact on rate and their impact on 2222Na Na production in ONe novae and production in ONe novae and x-ray burstsx-ray bursts

J.M. D’Auria et al., PRC 69, 065803 (2004).

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Summary of Summary of 2121Na(p,Na(p,γγ))2222MgMg

EExx (keV) (keV) EEcmcm (keV) (keV) ΓΓ (keV) (keV) ωγωγ (meV) (meV)

57145714 205.7 205.7 ± 0.5± 0.5 1.03 1.03 ± 0.21± 0.21

58375837 329329 ≤ ≤ 0.290.29

59625962 454 454 ± 5± 5 0.86 0.86 ± 0.29± 0.29

60466046 538 538 ± 13± 13 11.5 11.5 ± 1.4± 1.4

62466246 738.4 738.4 ± 1.0± 1.0 219 219 ± 25± 25

63296329 821.3 821.3 ± 0.9± 0.9 16.1 ± 2.816.1 ± 2.8 556 556 ± 77± 77

66096609 1101.1 1101.1 ± 2.5± 2.5 30.1 ± 6.530.1 ± 6.5 368 368 ± 62± 62

J.M. D’Auria et al., PRC 69, 065803 (2004).

Resonance Strengths and EnergiesResonance Strengths and Energies

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BGO ArrayBGO Array

D.G. Gigliotti et al., NIM B 204, 671 (2003).D.G. Gigliotti, M.Sc. thesis, University of Northern BC.

• Efficiency 1 - 10 MeV gammasEfficiency 1 - 10 MeV gammas– 60-72% (0.5 MeV threshold)60-72% (0.5 MeV threshold)

– 45-60% full Geant simulation45-60% full Geant simulation

• FWHM at 6.13 MeV (FWHM at 6.13 MeV (244244Cm/Cm/1313C)C)– Averages 7% for all detectorsAverages 7% for all detectors

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γγ--γγ Correlation AnalysisCorrelation Analysis

• Received 10Received 1099 2121Na per second Na per second from ISAC onto Hfrom ISAC onto H22 gas target gas target

• Detect multiple gammas in the Detect multiple gammas in the BGO arrayBGO array

• Propose decays and spin Propose decays and spin assignments, guided by assignments, guided by analogue states in the mirror analogue states in the mirror nucleus nucleus 2222Ne Ne

• Future: working on using our Future: working on using our GEANT simulation to possibly GEANT simulation to possibly extract branching ratiosextract branching ratios

C.C. Jewett, Ph.D. thesis, Colorado School of Mines.

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738 keV Resonance738 keV Resonance

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The three ResonancesThe three Resonances

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Revisiting the 1101 keV resonanceRevisiting the 1101 keV resonance

• Different gamma distribution Different gamma distribution at the low-energy tailat the low-energy tail

• TUDA suggested ~1080 keVTUDA suggested ~1080 keV• Extended our measurements Extended our measurements

down to lower energydown to lower energy– See resonanceSee resonance

– Twice as intenseTwice as intense

C.C. Jewett, Ph.D. thesis, Colorado School of Mines.

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2222Mg Mg γγ--γγ Analysis Analysis ResultsResults

2222MgMg Mirror Nucleus Mirror Nucleus 2222NeNebb

EExx (keV) (keV)aa Level (kev)Level (kev) Proposed JProposed Jππ Level (keV)Level (keV) JJππ

1101.1 1101.1 ± 2.5± 2.5 66096609 2+2+ 68176817 2+2+

821.3 821.3 ± 0.9± 0.9 63296329 1+1+ 68536853 1+1+

738.4 738.4 ± 1.0± 1.0 62466246 4+4+ 63456345 4+4+

~1079~1079 65876587

a J.M. D’Auria et al., PRC 69, 065803 (2004).b R.B. Firestone, Table of Isotopes, 8th Edition, 1996.

Consistent with results from the TUDA group: C. Ruiz et al., PRC 65, 042801(R) (2002). C. Ruiz, Ph.D. Thesis, University of Edinburgh (2003).

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2626Al(p,Al(p,γγ))2727Si - 188 keV resonanceSi - 188 keV resonance

• 7652 keV level7652 keV level• Dominating resonance in Dominating resonance in 2626Al+p Al+p

for novaefor novae• A change in A change in ωγωγ by 1/3 would by 1/3 would

change the final abundance of change the final abundance of 2626Al Al by a factor of 2by a factor of 2

• Weak, poorly-known resonanceWeak, poorly-known resonance– High 0.29 meVHigh 0.29 meV

– Low 10Low 10-5-5 meV meV

– Adopted value 0.064 meVAdopted value 0.064 meV

• DRAGON will use the 7828 keV DRAGON will use the 7828 keV level (363 keV resonance) for level (363 keV resonance) for commissioningcommissioning

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2626Al(p,Al(p,γγ))2727Si - CommissioningSi - Commissioning

• 363 keV resonance363 keV resonance• SiC target optimized for SiC target optimized for 2626AlAl

– 101088 per second per second

– 1:20 000 1:20 000 26m26mAlAl

– 1:200 1:200 2626NaNa

• Preliminary Preliminary ωγωγ 60 60 ±±14 meV14 meV– cf. 65 cf. 65 ±±18 meV18 meV

26Al(p,)27Si 363 keV

27Si recoils

L. Buchmann et al., NPA 415, 93 (1984).

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SummarySummary

• DRAGON is a working facilityDRAGON is a working facility• (Almost) Completed (Almost) Completed 2121Na(p,Na(p,γγ))2222MgMg

– Extending to Extending to γγ--γγ Analysis Analysis

• Stable beams programmeStable beams programme– 1212C(C(αα,,γγ))1616OO– 1212C(C(1212C,C,γγ))2424MgMg

• Beginning Beginning 2626Al(p,Al(p,γγ))2727SiSi• Exciting futureExciting future

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DRAGON E824 CollaborationDRAGON E824 Collaboration

Colorado School of MinesColorado School of MinesUwe Greife

Cybele Jewett

Simon Fraser UniversitySimon Fraser UniversityShawn Bishop (RIKEN)

John D’AuriaMike Lamey (Notre Dame)

Chris RuizChris Wrede (Yale)

TRIUMFTRIUMFLothar Buchmann

Don Hunter (Langara)Dave Hutcheon

Alison Laird (York)Art Olin

Dave OttewellMarcello Pavan

Joel RogersMike Trinczek

Mike AndersonKathryn OraasAndres Ruberg

University of Northern BCUniversity of Northern BCDario Gigliotti

Ahmed Hussein

McMaster UniversityMcMaster UniversityAlan Chen

Jonty Pearson

Yale UniversityYale UniversityRachel LewisPeter Parker

Ruhr-UniversitRuhr-Universitäät, Bochumt, BochumSabine Engel

Universitat Politécnica de CatalunyaUniversitat Politécnica de CatalunyaJordi José

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Documents

Direct Measurement of the 21 Na(p, γ ) 22 Mg Reaction: Resonance Strengths and γ - γ Analysis