simulation tool for lifetime measurements · 2008. 7. 9. · simulation tool for lifetime...
TRANSCRIPT
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Simulation tool for lifetime measurements
D. Mengoni
Università e Sezione INFN di Padova, Italia.
Agata Week, Uppsala - SwedenJuly 8th ÷ 11th, 2008
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 1 / 12
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Outline
1 ExperimentApparatusWorking principle
2 SimulationFrameworkEvent generatorResults
3 Conclusion
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 2 / 12
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CLARA-PRISMA set-up
CLARA: 25 Euroball cloversEfficiency ∼ 3% (Eγ 1.3 MeV) → 1%
P/T ∼ 45%
FWHM ∼ 10 keV (v/c=10%) → 6 keV
A. Gadea et al., Eur. Phys. J. A20 (2004) 193.
PRISMA: magnetic spectrometerSolid angle ∼ 80 msr
Mom. acceptance ± 10%
Maximum rigidity1.2 Tm
Energy resolution 1/1000
Mass resolution 1/300 FWHM
A.M. Stefanini et al., Nucl. Phys. A701 (2002) 109c.
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 3 / 12
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Tracking of PRISMA
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 4 / 12
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Working principle
J.J. Valiente, D. Mengoni et al., LNL An.Rep. 2007.
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 5 / 12
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AD-PRISMA set-up
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 6 / 12
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FrameworkRealistic physics
0
20
40
60
80
100
120
140
900 1000 1100 1200
Cou
nts
Energy (keV)
D = 1209 µm50Ca2+ --> 0+
generatorC code
Tracking
PSA
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 7 / 12
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Event generator
Two information streams: gammas towards the AD andprojectile-like heavy nuclei towards PRISMA.
Inclusion of target-degrader effect: effective thickness of thedegrader.
Velocity of the ion derived from the exp. one measured inPRISMA.
Output format: fully compatible with AGATA.
Stand-alone PRISMA tool: trajectory reconstruction, stoppingpower, AGATA input format, output suitable for tracked gammasmerging.
http://agata.pd.infn.it, http://www.lnl.infn.it/∼docserv/
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 8 / 12
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The 50Ca case:CLARA-PRISMAComparison between simulated and experimental data (τ ∼100 ps)
0
100
200
0
100
Cou
nts
900 1000 1100 1200Energy (keV)
0
20
40
2+ 0
+ 50Ca Distance = 300µm
Distance = 1209µm
Distance = 2223µm
After degraderBefore degrader
a)
b)
c)
Is
Iu
0
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40
60
900 1000 1100
Energy (keV)
D = 2223 µm
0
20
40
Cou
nts D = 1209 µm
0
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60
80
100
D = 300 µm
50Ca
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 9 / 12
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The 50Ca case:AD-PRISMAComparison between simulated and experimental data
0
100
200
300
400
900 1000 1100
Energy (keV)
D = 2223 µm
0
100
200
Cou
nts D = 1209 µm
0 100 200 300 400 500 600 700
D = 300 µm
50Ca
0 100 200 300 400 500 600 700
1000
Energy (keV)
D = 300 µm
0 20 40 60 80
100 120 140 160 180 200
Cou
nts D = 1240 µm
0 50
100 150 200 250 300 350
D = 2200 µm
50Ca
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 10 / 12
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46Ar lifetime derivationWeakening of N=28?
fully shifted peak for D=30µm (short lifetime) ⇒ simulation!
0
5
10
15
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1400 1600 1800 2000
Energy (keV)
D = 30 µm
0
5
10
15
20
Cou
nts D = 100 µm
0
5
10
15
20
D = 300 µm
46Ar
0
5
10
15 0
0.01
0.02
0.03
0.04
0.05
42 43 44 45 46 47 48 1
1.5
B(E2:0+->2+)[e2b2]
E2+->0+(MeV)
Mass
BE2-MNTBE2-Coulex
Energy
PRELIMINARY
H. Scheit et al., Phys. Rev. Lett 77 (1996) 3967.
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 11 / 12
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Outlook and Conclusions
The novel method for lifetime measurement in neutron-rich nucleican be succesfully simulated.
Possibility to fully simulate experiment: 52Ca with the AD +PRISMA + Köln Plunger (LoI already submitted.)
Derivation of lifetime otherwise impossible to extract from exp.data.
... near futureTwo body MNT generator: selected nucleus and angle using a giveninput file (grazing code) including cross section for a selected channel.
D. Mengoni (INFN-Pd) Simulation July 8÷11, 2008 12 / 12
ExperimentApparatusWorking principle
SimulationFrameworkEvent generatorResults
Conclusion