Tracking saddle-to-scission dynamics using N/Z in projectile
breakup reactions
SYLVIE HUDANApril 1, 2012
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Dynamical Breakup
Montoya et al., PRL73, 3070 (1994); Bocage et al., NPA676, 391 (2000)
Davin et al., PRC65, 064614 (2002); Colin et al., PRC67, 064603 (2003)
McIntosh et al., PRC81, 034603 (2010)
From Colin et al.
Observation of strongly aligned decay in mid-peripheral collisions at intermediate energies with:
Large yieldLarge relative velocity relative to fission
S. Hudan et al., PRC71, 05402 (2006)
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Dynamical Breakup
➡ Transiently deformed nuclei➡ Early cluster production
Montoya et al., PRL73, 3070 (1994); Bocage et al., NPA676, 391 (2000)
Davin et al., PRC65, 064614 (2002); Colin et al., PRC67, 064603 (2003)
McIntosh et al., PRC81, 034603 (2010)
From Colin et al.
Observation of strongly aligned decay in mid-peripheral collisions at intermediate energies with:
Large yieldLarge relative velocity relative to fission
S. Hudan et al., PRC71, 05402 (2006)
AMD
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Dynamical Breakup
➡ Transiently deformed nuclei➡ Early cluster production
Montoya et al., PRL73, 3070 (1994); Bocage et al., NPA676, 391 (2000)
Davin et al., PRC65, 064614 (2002); Colin et al., PRC67, 064603 (2003)
McIntosh et al., PRC81, 034603 (2010)
From Colin et al.
Observation of strongly aligned decay in mid-peripheral collisions at intermediate energies with:
Large yieldLarge relative velocity relative to fission
S. Hudan et al., PRC71, 05402 (2006)
AMD
What is the isotopic composition of those fragments?
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Experimental Setup124Xe 124Sn 112Sn1.30 1.48 1.24
FIRST: T. Paduszynski et al., NIMA 547, 464 (2005)
124(,136)Xe + 112, 124Sn @ 49.2 MeV/AExperiment performed at GANIL (France)
N/Z
BEAM
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Experimental Setup124Xe 124Sn 112Sn1.30 1.48 1.24
FIRST: T. Paduszynski et al., NIMA 547, 464 (2005)
124(,136)Xe + 112, 124Sn @ 49.2 MeV/AExperiment performed at GANIL (France)
N/Z
BEAM
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Experimental Setup
• T1: Si-Si-CsI(Tl)- 2.8° ≤ θLab ≤ 6.6°- Z = 1-55; A for Z = 1-14
124Xe 124Sn 112Sn1.30 1.48 1.24
273µm Si(IP) 1001µm Si(IP) 3.3cm CsI(Tl)/PD
48 rings 16 “pies”
48 rings 16 “pies” 16 “pies”
FIRST: T. Paduszynski et al., NIMA 547, 464 (2005)
124(,136)Xe + 112, 124Sn @ 49.2 MeV/AExperiment performed at GANIL (France)
N/Z
BEAM
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Experimental Setup
• T1: Si-Si-CsI(Tl)- 2.8° ≤ θLab ≤ 6.6°- Z = 1-55; A for Z = 1-14
• T2: Si-CsI(Tl)- 7.3° ≤ θLab ≤ 14.3°- Z = 1-24; A for Z=1-8
124Xe 124Sn 112Sn1.30 1.48 1.24
273µm Si(IP) 1001µm Si(IP) 3.3cm CsI(Tl)/PD
48 rings 16 “pies”
48 rings 16 “pies” 16 “pies”
16 rings (x4 quadrants) 16 “pies”
16 “pies”
3.3 cm CsI(Tl)/PD 500µm Si(IP)
FIRST: T. Paduszynski et al., NIMA 547, 464 (2005)
124(,136)Xe + 112, 124Sn @ 49.2 MeV/AExperiment performed at GANIL (France)
N/Z
BEAM
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Experimental Setup
• T1: Si-Si-CsI(Tl)- 2.8° ≤ θLab ≤ 6.6°- Z = 1-55; A for Z = 1-14
• T2: Si-CsI(Tl)- 7.3° ≤ θLab ≤ 14.3°- Z = 1-24; A for Z=1-8
• LASSA: 36.4° ≤ θLab ≤ 51.5°• DEMON: n TOF
124Xe 124Sn 112Sn1.30 1.48 1.24
273µm Si(IP) 1001µm Si(IP) 3.3cm CsI(Tl)/PD
48 rings 16 “pies”
48 rings 16 “pies” 16 “pies”
16 rings (x4 quadrants) 16 “pies”
16 “pies”
3.3 cm CsI(Tl)/PD 500µm Si(IP)
FIRST: T. Paduszynski et al., NIMA 547, 464 (2005)
124(,136)Xe + 112, 124Sn @ 49.2 MeV/AExperiment performed at GANIL (France)
N/Z
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Aligned Decay Angle between the relative velocity and the fragment “parent” velocity
ZH
ZL
α
TLF*
npvREL
vc.m.
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Aligned Decay
• Asymmetric angular distributions• Larger asymmetry for lighter ZL
• Asymmetry persists up to ZL = 18• Similar yield for n-rich target*
Angle between the relative velocity and the fragment “parent” velocity
ZH
ZL
α
TLF*
npvREL
vc.m.
*: Backward enhancement observed in Sn+Ni for change of target and projectile
P. Russotto et al., PRC 81, 064605 (2010)
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Isotopic Composition vs Rotation Angle
• Backward emission neutron-rich relative to forward emission
• Fragment neutron content enhanced for larger alignment
• No visible target effect of the relative neutron composition
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Relative Velocity Dependence
90°-180°66°-90°37°-66°0°-37°
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Relative Velocity Dependence• ⟨N⟩/Z decreases with vREL for forward decay (Coulomb effect)
• ⟨N⟩/Z increases with vREL for backward decay
90°-180°66°-90°37°-66°0°-37°
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Relative Velocity Dependence• ⟨N⟩/Z decreases with vREL for forward decay (Coulomb effect)
• ⟨N⟩/Z increases with vREL for backward decay
• All backward decays show the same dependence with vREL
90°-180°66°-90°37°-66°0°-37°
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Relative Velocity Dependence
More aligned decay with higher vREL ⇒ observed angular dependence
• ⟨N⟩/Z decreases with vREL for forward decay (Coulomb effect)
• ⟨N⟩/Z increases with vREL for backward decay
• All backward decays show the same dependence with vREL
90°-180°66°-90°37°-66°0°-37°
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Time Extraction
t = 0
• The rotation angle can be related to time via the rotational frequency ω:
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Time Extraction
t =α
ω
t = 0
• The rotation angle can be related to time via the rotational frequency ω:
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Time Extraction
t =α
ω
t
t = 0
• The rotation angle can be related to time via the rotational frequency ω:
•ω in the range 0.7-0.6 1021 rad/s corresponding to based on previous studies*.
� ≈ 40�
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Time Extraction
t =α
ω
*: G. Casini et al., PRL 71, 2567 (1993)
t = T/4
t = 0
• The rotation angle can be related to time via the rotational frequency ω:
•ω in the range 0.7-0.6 1021 rad/s corresponding to based on previous studies*.
• The correlation between <vREL> and the rotation angle is monotonous (5th degree polynom parametrization).
� ≈ 40�
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Time Extraction
t =α
ω
*: G. Casini et al., PRL 71, 2567 (1993)
t = T/4
t = 0
• The rotation angle can be related to time via the rotational frequency ω:
•ω in the range 0.7-0.6 1021 rad/s corresponding to based on previous studies*.
• The correlation between <vREL> and the rotation angle is monotonous (5th degree polynom parametrization).
vREL ⇒ angle ⇒ time
� ≈ 40�
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Time Extraction
t =α
ω
*: G. Casini et al., PRL 71, 2567 (1993)
t = T/4
t = 0
April 1, 2012Sylvie Hudan, APS April Meeting 2012
N/Z Time Dependence
66°-90° 37°-66°0°-37°
1 zs = 10-21 s
April 1, 2012Sylvie Hudan, APS April Meeting 2012
N/Z Time Dependence
• ZL = 4• Strong time dependence• Two components
66°-90° 37°-66°0°-37°
1 zs = 10-21 s
April 1, 2012Sylvie Hudan, APS April Meeting 2012
N/Z Time Dependence
• ZL = 4• Strong time dependence• Two components
• ZL = 5,6• Time dependence not as pronounced as for ZL = 4
66°-90° 37°-66°0°-37°
1 zs = 10-21 s
April 1, 2012Sylvie Hudan, APS April Meeting 2012
N/Z Time Dependence
• ZL = 4• Strong time dependence• Two components
• ZL = 5,6• Time dependence not as pronounced as for ZL = 4
• ZL = 8• Similar dependence for both short and long times
66°-90° 37°-66°0°-37°
1 zs = 10-21 s
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Conclusions
April 1, 2012Sylvie Hudan, APS April Meeting 2012
ConclusionsThe ⟨N⟩/Z of fragments emitted in dynamical decay is correlated with the rotation angle.Different vREL dependence are observed for forward and backward emission.For backward decays, ⟨N⟩/Z increases with vREL with a similar magnitude for all angles.Evolution of ⟨N⟩/Z over 2-3 zs (600-900 fm/c)
April 1, 2012Sylvie Hudan, APS April Meeting 2012
ConclusionsThe ⟨N⟩/Z of fragments emitted in dynamical decay is correlated with the rotation angle.Different vREL dependence are observed for forward and backward emission.For backward decays, ⟨N⟩/Z increases with vREL with a similar magnitude for all angles.Evolution of ⟨N⟩/Z over 2-3 zs (600-900 fm/c)
Difference in ⟨N⟩/Z time dependence for different ZL may be related to differences in the initial di-nuclear configuration (different position relative to saddle and scission points).In the future, use of damped reactions at radioactive beam facilities?
April 1, 2012Sylvie Hudan, APS April Meeting 2012
Collaboration and AcknowledgementsIndiana University: A.B. McIntosh, S. Hudan, J. Black, D. Mercier, C.J. Metelko, R. Yanez, R.T. de Souza
GANIL: A. Chbihi
GSI: S. Bianchin, C. Schwarz, W. Trautmann
Université Laval, Québec: M.O. Frégeau, J. Gauthier, J. Moisan, R. Roy
WMU: M. Famiano
Thanks to:• The support of the GANIL staff and facility• The DEMON collaboration
This work was supported by the DOE Office of Science under the Grant No. DEFG02-88ER-40404