1. Piotr Bednarczyk
SPES LETTER OF INTENT   High spin g-ray spectroscopy of heavy, octupole deformed Ac and Fr nuclei produced in fusion-evaporation reactions with the intense A~90 Rb radioactive beams at SPES

2. Collaboration
P.Bednarczyk, M.Ciemała, B.Fornal, J.Grębosz, M.Kmiecik, W.Królas, M.Krzysiek, A.Maj, M.Matejska-Minda, W.Męczyński, B.Wasilewska, M.Ziębliński
H. Niewodniczański Institute of Nuclear Physics PAN, Kraków, Poland
G. Jaworski, M. Komorowska, P. Napiorkowski, M.Palacz
HIL, University of Warsaw, Poland,
D.Curien, J.Dudek,
IPHC, Strasbourg, France,
G. de Angelis, V. Modamio, D.R. Napoli, J. Valiente
LNL, Legnaro, Italy,
A.Boso, D. Bazzacco, S. Lenzi, S. Lunardi, R.Menegazzo, D.Mengoni, F. Recchia
INFN sezione di Padova, Padova, Italy,
A.Bracco, G. Benzoni, F. Camera, F. Crespi, S.Leoni , B. Million. O. Wieland
Università degli Studi and INFN sezione di Milano, Milano, Italy

3. Fusion-evaporation with RIB
Test of feasibility
Fusion-evaporation with RIB
The strongest available beam
Interesting physics case
Efficient gamma and ancillary detector setup

4. SPES beams- fission on UCx
90-92Rb
133,135I
Day1 (5mA) reduction factor of ~100

5. Onset of octupole deformed shapes in actinides at N~130, Z~88
Reflection asymmetric shapes
224Ra
Gaffney et al.,
Nature 497, 199 (2013)
Simplex symmetry:
Even A
s=+1 Ip= 0+, 1-, 2+, 3-,…
s=-1 Ip= 0-, 1+, 2-, 3+,…
Odd A
s=+i 2Ip= 1+, 3-, 5+,…
s=-i 2Ip= 1-, 3+, 5-, …
Alternative parity bands
Debray PRC 73(2006)

6. Experimental investigation of alternative parity bands in actinides
Schultz 1992
Beams : C, O, N
Targets: Pb, Bi
Max.Spin J~20h
209Bi(12-14C, xn) Ac
Alternative parity bands
12C
14C
209Bi
224Ra
RIB COULEX

7. Alternative use of a symmetric reaction with a RIB
RIB: 90-92Rb at 109(7) pps
Target: 130Te c
High spins ?

8. Increase of angular momentum
PACE4
sresid = 150 mb
sfission = 75-95%
sresid = 70 mb
High spin states: 130Te(92Rb, 4n)218Ac
Eb = 375MeV,
v/c > 4%

9. g-spectroscopy at high spin and temperture
220CN E*
fission
E1 (GDR) n
octupole-quadrupole shape transition at HS
PARIS
Multiplicity
High energy g ?
AGATA
discrete g J

10. g-spectroscopy at high spin and temperture
220CN E*
fission
E1 (GDR) n
PARIS
Multiplicity
High energy g ?
AGATA
discrete g J
+ ancillary detector to suppres fission and perform Doppler correction

11. Recoil Filter Detector
ToF = T0 + Dt T0 Dt
GASP
RFD
coincidence of ER and g-rays
ToF technique allows to deduce actual velocity of every recoil and to filter out unwanted reaction channels:
scattered beam, Coulex, fission

12. Recoil Filter Detector
ToF = T0 + Dt T0 Dt
GASP
RFD
Set of fast 18 HI detectors (SEE)
W.Meczynski, et al, NIM A580, 1310 (2007)

13. Fission background reduction
218Ra: heart-shape nucleus:
quadrupole deformation + octupole phonon wave
Frauendorf PRC77(2008)
198Pt(26Mg,a2n) 218Ra
CN= 224Th
sresid(219,220Th)~ 10mb
sfiss~ 250mb (90%)
i< 1pnA
RIB:
130Te(93Kr,5n)218Ra
219,220Th
CN= 223Ra
sresid~ 200mb
sfiss ~ 150mb (40%)
exp. 2009, G. de Angelis et al.

14. 130Te(92Rb,4n)218Ac ToF RFD at GALILEO RFD angles Eb = 370MeV, fission
recoils
35%
beam
recoils
fission 1%
ang. distr
GEMINI++

15. Perspectives of using RFD at RIB
GAMMA-ray detector arrays
GALILEO
AGATA
PARIS
RFD advantages
High efficiency for recoils
Projectiles do not irradiate the setup and can be transported to a FC distant from the experimental area.
Detectors are not sensitive to any kind of radioactivity
Doppler broadening reduction
Fission background supression
Litetimes (DSAM)