Tracking saddle-to-scission dynamics using N/Z in ...nuchem.iucf.indiana.edu/Presentations/SylvieHudan_APS2012.pdfSylvie Hudan, APS April Meeting 2012 April 1, 2012 Dynamical Breakup

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)


Dynamical Breakup

➡ Transiently deformed nuclei➡ Early cluster production




From Colin et al.



S. Hudan et al., PRC71, 05402 (2006)

AMD


Dynamical Breakup

➡ Transiently deformed nuclei➡ Early cluster production




From Colin et al.



S. Hudan et al., PRC71, 05402 (2006)

AMD

What is the isotopic composition of those fragments?


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


Experimental Setup124Xe 124Sn 112Sn1.30 1.48 1.24



N/Z

BEAM


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”



N/Z

BEAM


Experimental Setup


• 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




16 rings (x4 quadrants) 16 “pies”

16 “pies”

3.3 cm CsI(Tl)/PD 500µm Si(IP)



N/Z

BEAM


Experimental Setup


• 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




16 rings (x4 quadrants) 16 “pies”

16 “pies”

3.3 cm CsI(Tl)/PD 500µm Si(IP)



N/Z


Aligned Decay Angle between the relative velocity and the fragment “parent” velocity

ZH

ZL

α

TLF*

npvREL

vc.m.


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)


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


Relative Velocity Dependence

90°-180°66°-90°37°-66°0°-37°


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°


Relative Velocity Dependence• ⟨N⟩/Z decreases with vREL for forward decay (Coulomb effect)


• All backward decays show the same dependence with vREL

90°-180°66°-90°37°-66°0°-37°


Relative Velocity Dependence

More aligned decay with higher vREL ⇒ observed angular dependence

• ⟨N⟩/Z decreases with vREL for forward decay (Coulomb effect)


• All backward decays show the same dependence with vREL

90°-180°66°-90°37°-66°0°-37°


Time Extraction

t = 0

• The rotation angle can be related to time via the rotational frequency ω:


Time Extraction

t =α

ω

t = 0



Time Extraction

t =α

ω

t

t = 0


•ω in the range 0.7-0.6 1021 rad/s corresponding to based on previous studies*.

� ≈ 40�


Time Extraction

t =α

ω

*: G. Casini et al., PRL 71, 2567 (1993)

t = T/4

t = 0



• The correlation between <vREL> and the rotation angle is monotonous (5th degree polynom parametrization).

� ≈ 40�


Time Extraction

t =α

ω

*: G. Casini et al., PRL 71, 2567 (1993)

t = T/4

t = 0



• The correlation between <vREL> and the rotation angle is monotonous (5th degree polynom parametrization).

vREL ⇒ angle ⇒ time

� ≈ 40�


Time Extraction

t =α

ω

*: G. Casini et al., PRL 71, 2567 (1993)

t = T/4

t = 0


N/Z Time Dependence

66°-90° 37°-66°0°-37°

1 zs = 10-21 s


N/Z Time Dependence

• ZL = 4• Strong time dependence• Two components

66°-90° 37°-66°0°-37°

1 zs = 10-21 s


N/Z Time Dependence


• ZL = 5,6• Time dependence not as pronounced as for ZL = 4

66°-90° 37°-66°0°-37°

1 zs = 10-21 s


N/Z Time Dependence


• 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


Conclusions


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)


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?


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

Documents

Tracking saddle-to-scission dynamics using N/Z in ...nuchem.iucf.indiana.edu/Presentations/SylvieHudan_APS2012.pdfSylvie Hudan, APS April Meeting 2012 April 1, 2012 Dynamical Breakup