b.mouginot ipno phd director : f. azaiez, s. franchoo
DESCRIPTION
B.MOUGINOT IPNO PHD director : F. AZAIEZ, S. FRANCHOO. Giant Pairing Vibration : Experimental Overview. How to populate a O+ state in Nuclei ?. Giant Pairing Vibration. GPV Mode : Collective Excitation of Pair in the Next Major Shell. Next Major Shell. Low-lying 0+ Excitation. - PowerPoint PPT PresentationTRANSCRIPT
B.MOUGINOTIPNO
PHD director : F. AZAIEZ, S. FRANCHOO
Giant Pairing Vibration :
Experimental Overview
Ground State 0+
First 0+ excited state A Higher excited 0+
Next M
ajor Shell
Giant Pairing VibrationGPV Mode : Collective Excitation of Pair
in the Next Major Shell
Low-lying 0+ Excitation
How to populate a O+ state in Nuclei ?
>Pairing vibrations : L=0
>Sensitive to Pairing interaction
Giant Pairing Vibrations
GPV
GPV is a Collective mode
> Should lie at high excitation energy
> 2 nucleon transfer channel selective for pairing vibration
ex (p,t) reaction
E. Khan PRC69(2004)
Overview of (p,t) reactions
Orihara Phys.Rev. C 9(1974)266
Data recorded at 8°- 65°
51.9MeV protons at Institute of Nuclear Study
Lanford Phys.Rev. C 16(1977)988
35MeV protons at MSU cyclotron :Data recorded at 6° 14° 30°
E* range : 0 - 10 MeV
E* range : 0 - 7 MeV
208Pb (p,t) 206Pb
208Pb (p,t) 206Pb
Position sensitive chamber at the focal plane of the spectrograph
>Data recorded at 7°- 35°
Shepard Nucl.Phys. A 322(1979)
40 MeV protons at Indiana University Cyclotron (IUCF)
Takahashi Phys.Rev.C 27(1983)
51.9 MeV protons at Institute of Nuclear Study Tokyo University
Array of 200 proportional countersat the focal plane of the spectrometer
>Data recorded at 2°- 60°
E* range : 0 - 6 MeV
E* range : 0 - 5 MeV
Mihailidis Phys.Rev.C 64(2001)
Gerlic Phys.Rev. C 39(1989)
168 MeV protons at K220 Orsay Synchrocyclotron
Vertical-wire Drift Chamber at focal plane of K600 spectrometer
Data recorded at 7°- 34°
Data recorded at 2°- 18°
120 MeV protons at IUCF
E* range : 0 - 12 MeV
E* range : 0 - 7 MeV
208Pb (p,t) 206Pb
40 MeV protons at University of Minnesota linear accelerator
Bassani Phys.Rev. 139(1965)
8 Plastic scintillators at the focal plane of the spectrometer
Data recorded at 7°-30°
120Sn (p,t) 118Sn
E* range : 0 - 11 MeV
89MeV protons at IUCF
Crawley et al. Phys.Rev. C 22(1980)
42 MeV protons at Jefferson labresistive-wire proportional counter at focal plane of Enge spectrometer
25000
Crawley et al. Phys.Rev.Lett. 39(1977)33
Data recorded at 10°- 45°
Data recorded at 15°- 45°
E* range : 0 - 50 MeV
E* range : 0 - 20 MeV
120,122Sn (p,t) 118,120Sn
Why revisit (p,t) reactions for GPV?On 208Pb :
>51.9 MeV proton at 8°- 65° : Orihara Phys.Rev. C 9(1974)266
>35 MeV proton at 6° 18° 30° : Lanford Phys.Rev. C 16(1977)988
>40 MeV proton at 7°- 35° : Shepard Nucl.Phys. A 322(1979)
>51.9 MeV proton at 6° 18° 30° : Takahashi Phys.Rev.C 27(1983)
>168 MeV proton at 2°-18° : Gerlic Phys.Rev. C 39(1989)
>120 MeV proton at 7°-34° : Mihailidis Phys.Rev.C 64(2001)
On 120Sn :
>40 MeV proton at 7°- 30° : Bassani Phys.Rev. 139(1965)
>42 MeV proton at 10°- 45° : Crawley et al. Phys.Rev.Let. 39(1977)33
>89MeV proton at 15°- 45° : Crawley et al. Phys.Rev. C 22(1980)
No experiment at the right angle and/or the right energy !!0°or very near 0°& 60 MeV
GPV predicted at 10-20MeV>wrong Energy Range
At iThemba (South-Africa) :208Pb(p,t)206Pb Q = -5.62 MeV120Sn(p,t)118Sn Q = -7.111 MeV
Spectrometer at 7°
Our recent work
Spectrometer at 7°
1 Wire Chamber : position of the light ejectile - triton energy
Proton beamTarget : 208Pb & 120Sn
tritons
1 Paddle : dE/TOF – triton selection
At 60 MeV
Selection of B window (5-7MeV)
thickness 6.4mm
AB
Z
2 Week-ends
B
p (208Pb,206Pb) t & p (120Sn,118Sn) t
Our recent work
Gate on Tritons
Without Gate
triton
deuteron
16O(p,t)
12C(p,t)
208Pb(p,d)207Pb Ground State
5/2-3/2-
13/2+
7/2-
Gate on Deuterons
Exemple for 41MeV setting
TOF
E p
addl
e1
16O(p,t)
12C(p,t)
No gate:
0,996triton gated
triton nongated
N
N
gated on tritons:
0,0019deuton gated
deuton nongated
N
N
Deuterons acceptance ratio :Tritons acceptance ratio :
Exemple for 41MeV setting
TOF
E p
addl
e1
Excitation Spectrum of 206Pb all fields overlapping
Excitation Spectrum of 206Pb all fields superimposed
Excited state of 206Pb
14O Ground state
10C Ground state
Excited state of 207Pb
So far no indication of bump or broad structure in the 206Pb spectrum
Excitation Spectrum of 120Sn all fields overlapping
Excitation Spectrum of 120Sn(p,t) :
GPV?Deep hole statesA hint for GPV in 120Sn: observation of cross-section enhancement
(weak bump) at Ex=12MeV?The GPV? If yes, should increase at 0°
Next Move : in SPRING 2009
120Sn(p,t)118Sn & 208Pb(p,t)206Pb
proton beam @ 60 MeV
K600 spectrometer @ 0°
N=70
Futur plans and improvments?
Thank you
iThemba labs
Excitation Spectrum of 1118Sn(p,t) :
GPV?Deep hole states
N=70
A hint for GPV in 120Sn: observation of cross-section enhancement (weak bump) at Ex=12MeV?
The GPV? If yes, should increase at 0°
GPV could be searched for using Pair Transfer Reactions
(t,p) reactions (p,t) reactions
At iThemba :208Pb(p,t)206Pb Q = -5.62 MeV120Sn(p,t)118Sn Q = -7.111 MeV
GPV : L = 0 pairing mode
Spectrometer at 0°
Futur plans and improvments?