Piotr Bednarczyk Instytut Fizyki Jdrowej im Henryka Niewodniczaskiego
Piotr Bednarczyk Instytut Fizyki Jądrowej im. Henryka Niewodniczańskiego Polskiej Akademii Nauk 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
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, Italy, A. Bracco, G. Benzoni, F. Camera, F. Crespi, S. Leoni , B. Million. O. Wieland Università degli Studi and INFN sezione di Milano, Italy 2 nd SPES Workshop LNL, 26 -28 May 2014
Test of feasibility Fusion-evaporation with RIB q q q The strongest available beam Interesting physics case Efficient gamma and ancillary detector setup 2 nd SPES Workshop LNL, 26 -28 May 2014
SPES beams- fission on UCx 133, 135 I I 90 -92 Rb q Day 1 (5 m. A) reduction factor of ~100 2 nd SPES Workshop LNL, 26 -28 May 2014
Onset of octupole deformed shapes in actinides at N~130, Z~88 Reflection asymmetric shapes 224 Ra Gaffney et al. , Nature 497, 199 (2013) Alternative parity bands Debray PRC 73(2006) Simplex symmetry: Even A s=+1 Ip= 0+, 1 -, 2+, 3 -, … s=-1 Ip= 0 -, 1+, 2 -, 3+, … Odd A s=+i 2 Ip= 1+, 3 -, 5+, … s=-i 2 Ip= 1 -, 3+, 5 -, … 2 nd SPES Workshop LNL, 26 -28 May 2014
Experimental investigation of alternative parity bands in actinides s=+1 1980 -1990 Beams : C, O, N Targets: Pb, Bi Schultz 1992 220 Ac s=-1 209 Bi(12 -14 C, xn)217 -220 Ac Alternative parity bands Max. Spin J~20 h 12 C 14 C 209 Bi 224 Ra RIB COULEX 2 nd SPES Workshop LNL, 26 -28 May 2014
Alternative use of a symmetric reaction with a RIB c RIB: 90 -92 Rb at 109(7) pps c Target: 130 Te High spins ? 2 nd SPES Workshop LNL, 26 -28 May 2014
Increase of angular momentum PACE 4 sresid = 150 mb sfission = 75 -95% sresid = 70 mb High spin states: 130 Te(92 Rb, 4 n)218 Ac Eb = 375 Me. V, v/c > 4% 2 nd SPES Workshop LNL, 26 -28 May 2014
g-spectroscopy at high spin and temperture 220 CN E* fission E 1 (GDR) n octupole-quadrupole shape transition at HS PARIS Multiplicity High energy g ? AGATA discrete g J 2 nd SPES Workshop LNL, 26 -28 May 2014
g-spectroscopy at high spin and temperture 220 CN E* fission E 1 (GDR) n PARIS Multiplicity High energy g ? AGATA discrete g J + ancillary detector to suppres fission 2 SPES Workshop and perform Doppler correction LNL, 26 -28 May 2014 nd LNL, 26 -28 May 2014
Recoil Filter Detector GASP RFD q coincidence of ER and g-rays q To. F technique allows to deduce actual velocity of every recoil and to filter out unwanted reaction channels: T 0 To. F = T 0 + Dt Dt scattered beam, Coulex, fission 2 nd SPES Workshop LNL, 26 -28 May 2014
Recoil Filter Detector GASP T 0 RFD To. F = T 0 + Dt Dt Set of fast 18 HI detectors (SEE) W. Meczynski, et al, NIM A 580, 1310 (2007) 2 nd SPES Workshop LNL, 26 -28 May 2014
Fission background reduction 218 Ra: heart-shape nucleus: quadrupole deformation + octupole phonon wave Frauendorf PRC 77(2008) 198 Pt(26 Mg, a 2 n) 218 Ra CN= 224 Th sresid(219, 220 Th)~ 10 mb sfiss~ 250 mb (90%) i< 1 pn. A RIB: 219, 220 Th exp. 2009, G. de Angelis et al. 130 Te(93 Kr, 5 n)218 Ra CN= 223 Ra sresid~ 200 mb sfiss ~ 150 mb (40%) 2 nd SPES Workshop LNL, 26 -28 May 2014
RFD at GALILEO 130 Te(92 Rb, 4 n)218 Ac To. F fission 1% beam Eb = 370 Me. V, recoils 35% RFD angles fission recoils ang. distr GEMINI++ 2 nd SPES Workshop LNL, 26 -28 May 2014
Perspectives of using RFD at RIB q GAMMA-ray detector arrays Ø GALILEO Ø AGATA Ø PARIS q RFD advantages Ø Doppler broadening reduction Ø Fission background supression Ø Litetimes (DSAM) Ø High efficiency for recoils Ø Projectiles do not irradiate the setup and can be transported to a FC distant from the experimental area. Ø Detectors are not sensitive to any kind of radioactivity 2 nd SPES Workshop LNL, 26 -28 May 2014
- Slides: 15