Inverse kinematic studies of 12C(α,γ 16O with · PDF fileInverse kinematic studies...

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Transcript of Inverse kinematic studies of 12C(α,γ 16O with · PDF fileInverse kinematic studies...

  • Ruhr-Universitt BochumLehrstuhl fr Physik mit Ionenstrahlen (EP III)

    Nukleare AstrophysikProf. Dr. C. Rolfs

    Inverse kinematic studies of12C(,)16O with ERNA

    Daniel SchrmannERNA Collaboration

    The Status of 12C(,)16O, the Holy Grail of Nuclear Astrophysics, Caltech 2006/12/15

  • Recoil Separator ERNA:an alternative approach to measure the reaction 12C(,)16O

    ion sourcedynamitron

    tandem accelerator

    ion beam purification

    Gastarget & Post-Stripper

    singlet

    60 magnet

    E-Etelescope

    recoilseparation

    doubletanalysingmagnet

    recoilfocussing

    Wien filter

    Wien filter Wien filter

    Wien filter

    magneticquadrupolemultiplets

    triplet

    side FC

    Nrecoils detected = Nprojectiles ntarget TERNA pqRequirements

    angular / energy acceptance knowledge of charge state distribution high purity of incoming 12C beam suppression of 12C beam

    Advantageshigh efficiency ~pqmeasure totindependent of s(mostly) background free-ray coincidences possible

  • FromFrom CaltechCaltech to Bochumto Bochum

  • Recoil Separator ERNA:an alternative approach to measure the reaction 12C(,)16O

    ion sourcedynamitron

    tandem accelerator

    ion beam purification

    Gastarget & Post-Stripper

    singlet

    60 magnet

    E-Etelescope

    recoilseparation

    doubletanalysingmagnet

    recoilfocussing

    Wien filter

    Wien filter Wien filter

    Wien filter

    magneticquadrupolemultiplets

    triplet

    side FC

    Nrecoils detected = Nprojectiles ntarget TERNA pqRequirements

    angular / energy acceptance knowledge of charge state distribution high purity of incoming 12C beam suppression of 12C beam

    Advantageshigh efficiency ~pqmeasure totindependent of s(mostly) background free-ray coincidences possible

  • GastargetGastarget

    Density Determination Energy Loss (Stopping Power) 7Li(,)11B 7Li(,)7Li*

    Position [mm]-150 -100 -50 0 50 100 150

    Aus

    beut

    e [a

    .U.]

    -510

    -410

    -310

    -210

    -110Messung upstream (d=2 mm)

    Messung downstream (d=2 mm)

    Messung ausserhalb (d=4 mm)

    Integrand

  • Recoil Separator ERNA:an alternative approach to measure the reaction 12C(,)16O

    ion sourcedynamitron

    tandem accelerator

    ion beam purification

    Gastarget & Post-Stripper

    singlet

    60 magnet

    E-Etelescope

    recoilseparation

    doubletanalysingmagnet

    recoilfocussing

    Wien filter

    Wien filter Wien filter

    Wien filter

    magneticquadrupolemultiplets

    triplet

    side FC

    Nrecoils detected = Nprojectiles ntarget TERNA pqRequirements

    angular / energy acceptance knowledge of charge state distribution high purity of incoming 12C beam suppression of 12C beam

    Advantageshigh efficiency ~pqmeasure totindependent of s(mostly) background free-ray coincidences possible

  • Charge State DistributionCharge State Distribution

  • Charge State DistributionCharge State Distributionelectron losselectron loss

    pressure p[mbar]0 1 2 3 4 5

    prob

    abili

    ty

    0

    0.2

    0.4

    0.6

    0.8

    1

    pressure p[mbar]0 1 2 3 4 5

    prob

    abili

    ty

    0

    0.2

    0.4

    0.6

    0.8

    1

    calculatedqrecoil = qcarbon

    measured

    qrecoil = qcarbon +2

    12C3+ 16O6+

    Ecm=3.2 MeV

    pressure [mbar]0 1 2 3 4 5

    prob

    abili

    ty [%

    ]

    0

    10

    20

    30

    40

    50

    60

    70

    80

    90

    100q=3+q=4+q=5+q=6+q=7+

    16 3+ 4O 9.60 MeV in He

    inte

    grat

    e

    Solution:post-target stripper

  • Recoil Separator ERNA:an alternative approach to measure the reaction 12C(,)16O

    ion sourcedynamitron

    tandem accelerator

    ion beam purification

    Gastarget & Post-Stripper

    singlet

    60 magnet

    E-Etelescope

    recoilseparation

    doubletanalysingmagnet

    recoilfocussing

    Wien filter

    Wien filter Wien filter

    Wien filter

    magneticquadrupolemultiplets

    triplet

    side FC

    Nrecoils detected = Nprojectiles ntarget TERNA pqRequirements

    angular / energy acceptance knowledge of charge state distribution high purity of incoming 12C beam suppression of 12C beam

    Advantageshigh efficiency ~pqmeasure totindependent of s(mostly) background free-ray coincidences possible

  • AcceptanceAcceptanceMatrix calculations:COSY INFINITY

    These jus

    t give ST

    ARTING v

    alues:

    Tune Sep

    arator wit

    h 16O pil

    ot beam!

    Good tuning

    Bad tuning

  • Angular acceptanceAngular acceptance

    Ecm = 2.4 MeV qrec = 6+

  • AngularAngular AcceptanceAcceptance

    [mrad]-40 -30 -20 -10 0 10 20 30 40

    Tran

    smis

    sion

    0

    0.2

    0.4

    0.6

    0.8

    1

    Bext. Triplet changed by 0.7% !

  • Energy AcceptanceEnergy Acceptance

    -20 -15 -10 -5 0 5 10 15 200.0

    0.2

    0.4

    0.6

    0.8

    1.0

    trans

    mis

    sion

    E / E0 [ % ]experimental

    calculated

    by variation of beam energy

  • Recoil Separator ERNA:an alternative approach to measure the reaction 12C(,)16O

    ion sourcedynamitron

    tandem accelerator

    ion beam purification

    Gastarget & Post-Stripper

    singlet

    60 magnet

    E-Etelescope

    recoilseparation

    doubletanalysingmagnet

    recoilfocussing

    Wien filter

    Wien filter Wien filter

    Wien filter

    magneticquadrupolemultiplets

    triplet

    side FC

    Nrecoils detected = Nprojectiles ntarget TERNA pqRequirements

    angular / energy acceptance knowledge of charge state distribution high purity of incoming 12C beam suppression of 12C beam

    Advantageshigh efficiency ~pqmeasure totindependent of s(mostly) background free-ray coincidences possible

  • Typical E-E Spectra

    Ecm = 4.4 MeVsuppression ~ 3109

    Ecm = 2.2 MeVsuppression ~ 11011

  • SuppressionSuppression

    E [MeV]1.5 2 2.5 3 3.5 4 4.5 5

    Rat

    e R

    910

    1010

    1110

    R = # beam particles# leaky beam in E-E

  • 1212C(C(,,))1616O total cross O total cross sectionsection

    [MeV]cmE2 2.5 3 3.5 4 4.5 5

    [nb]

    -110

    1

    10

    210

    310

    410

    -1

    +2+4 +4

    +2

    +0

  • Background ?Background ?

    Sources: 16O impurities in 12C beam scattering of 16O restgas 12C + 12C

  • Beam purification systemWien-Filters

    Purification WF: OFF On [channel]restE

    500 1000 1500 2000 2500 3000 3500 4000 [channel]restE

    0 500 1000 1500 2000 2500 3000 3500 4000

    E [c

    hann

    el]

    0

    500

    1000

    1500

    2000

    2500

    3000

    3500

    4000

    C12

    O16

    RT*50

    PO ~ 10-12PWF < 10-9

  • Background: Background: 1212C + C + 1212CC

    [channel]restE0 20 40 60 80 100 120 140

    E [c

    hann

    el]

    0

    20

    40

    60

    80

    100

    120

    140

    [channel]restE0 20 40 60 80 100 120 140

    restE0 50 100 150 200 250

    E

    0

    20

    40

    60

    80

    100

    120

    140

    160

    180

    200

    C (leaky beam)12

    O16

    restE0 50 100 150 200 250

    20

    40

    60

    80

    100

    120

    140

    160

    180

    200

    Ne20

    O16

    restE0 50 100 150 200 250

    1

    10

    210

    310

    pre target aperture-> Rate x50

    carbonfoil

  • Background ?Background ?

    Sources: 16O impurities in 12C beam 105 to small scattering of 16O restgas 102 to small 12C + 12C most probably !

    (but: background almost constant)

  • Comparison ERNA Calculation Kunz. et al.(Kunz R. et al., ApJ 567, 643-650 2002)

    Basic resonance properties well reproducedClear need for improved (new) R-Matrix calculation

  • ERNA CollaborationERNA CollaborationBochumBochumA. A. DiDi LevaLevaR. KunzR. KunzD. D. RogallaRogallaC. RolfsC. RolfsF. F. SchmannSchmannD. SchrmannD. SchrmannF. F. StriederStriederH.H.--P. P. TrautvetterTrautvetter

    Naples & CasertaN. De CesareL. GialanellaA. DOnofrioG. ImbrianiC. LubrittoA. OrdineV. RocaM. RomanoF. Terrasi

    Thank you!

  • Leaky BeamLeaky Beam

    qrecoil = 3+qcarbon, initial = 6+

    Triplet Wien Filter

  • [MeV]cmE2 2.5 3 3.5 4 4.5 5

    S(E

    ) [k

    eV-b

    arn

    ]

    10

    210

    310

    1-

    2+

    4+

    4+

    2+

    0+

    12C(,)16O total cross section

  • [MeV]cmE0.5 1 1.5 2 2.5 3

    [keV

    -bar

    n]E1S

    1

    10

    210

    E1 calcFey (Turntable)Fey (Eurogam)Kunzouellet

    [MeV]E0.5 1 1.5 2 2.5

    N

    1

    10

    210

    310

    410

    510

    16N decay

    [MeV]E0.5 1 1.5 2 2.5

    N

    1

    10

    210

    310

    410

    510

    16N decay

    [MeV]cmE0.5 1 1.5 2 2.5 3

    [keV

    -bar

    n]E1S

    1

    10

    210

    E1 calcFey (Turntable)Fey (Eurogam)Kunzouellet

    Fit to E1 groundstate data Assuncao et al.

  • E1 groundstate transition:5-6 MeV states

  • Charge State DistributionCharge State Distribution

  • --Recoil CoincidencesRecoil CoincidencesEcm = 2.4 MeV (1-)8x BaF2

    channel0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

    cou

    nts

    1

    10

    102

    103