PRISMA-FIDES 2013-2016PRISMA-FIDES 2013-2016Heavy-ion reactions from grazing collisions Heavy-ion reactions from grazing collisions tto o complete fusion complete fusion

G.Montagnoli (100%), D.Montanari (100%), F.Scarlassara (50%)(Univ. and INFN - Padova) 2.5 FTE

A.M. Stefanini (100%), L. Corradi (80%), E.Fioretto (100%), Huiming Jia (100%)(INFN - LNL) 3.8 FTE

G.Pollarolo (50%) (Univ. and INFN – Torino) 0.5 FTE

G.Montagnoli (100%), D.Montanari (100%), F.Scarlassara (50%)(Univ. and INFN - Padova) 2.5 FTE

A.M. Stefanini (100%), L. Corradi (80%), E.Fioretto (100%), Huiming Jia (100%)(INFN - LNL) 3.8 FTE

G.Pollarolo (50%) (Univ. and INFN – Torino) 0.5 FTE

July 2012

Joint work with the experiments EXOTIC and GAMMA

Collaboration with GSI (D.Ackermann), Zagreb (S.Szilner,T.Mijatovic), Dubna (N.Kondratiev, R.Sagaidak), Strasbourg (F.Haas, S.Courtin), Cracow (J.Grebosz)

Joint work with the experiments EXOTIC and GAMMA

Collaboration with GSI (D.Ackermann), Zagreb (S.Szilner,T.Mijatovic), Dubna (N.Kondratiev, R.Sagaidak), Strasbourg (F.Haas, S.Courtin), Cracow (J.Grebosz)

6.8 FTE overall

The PRISMA 2 experiment at LNLThe PRISMA 2 experiment at LNL

Traditionally, our group has always been involved in 2 lines of research:

HI fusion reactionsaround VB presently focused at E << VB

using the electrostatic beam separator PISOLO

2-body reactions pair transfer enhancement (transfer coupling to fusion n-rich isotope production ....)

using the magnetic spectrometer PRISMA

• Heavy-ion reactions from grazing collisions to complete fusion: recent experiments on sub-barrier transfer and on fusion hindrance at very low energies

• The AGATA demonstrator: nuclear structure of n-rich nuclei identified with PRISMA. At LNL until end of 2011. A small array of

LaBr3:Ce detectors.

• Heavy beams at LNL (Tandem, ALPI, PIAVE) and complementary experiments at other facilities (GANIL, ANL)

• Heavy-ion reactions from grazing collisions to complete fusion: recent experiments on sub-barrier transfer and on fusion hindrance at very low energies

• The AGATA demonstrator: nuclear structure of n-rich nuclei identified with PRISMA. At LNL until end of 2011. A small array of

LaBr3:Ce detectors.

• Heavy beams at LNL (Tandem, ALPI, PIAVE) and complementary experiments at other facilities (GANIL, ANL)

PRISMA-2

PRISMA

beam direction

20o

96Zr 40Ca

Detection of (light) target like ions in inverse kinematics with Detection of (light) target like ions in inverse kinematics with PRISMA PRISMA

Detection of (light) target like ions in inverse kinematics with Detection of (light) target like ions in inverse kinematics with PRISMA PRISMA

Nucleon transfer channels have been measured down to 25 % below the Coulomb barrier

Prisma acceptance

+1n well reproduced by theory in slope and absolute value

Same slope of +2n between theory and experiment

+1n well reproduced by theory in slope and absolute value

Same slope of +2n between theory and experiment

L. Corradi et al., Phys. Rev. C 84, 034603 (2011)

+2n enhancement due to the presence of other excited

states?

+2n enhancement due to the presence of other excited

states?

Absorption reproduced by theory

Absorption reproduced by theory

2n transfer to g.s.2n transfer to 0+ (5,76MeV)(2n in p3/2)

Sub-barrier transfer for 96Zr (beam) + 40Ca

Slopes for 116Sn + 60Ni

The experiment 116Sn + 60Ni (Feb. 2012)

PRELIMINARY

+1n and +2n slopes are in agreement with those expected from binding

energies

+1n and +2n slopes are in agreement with those expected from binding

energies

Preliminary dataData under analysis

Preliminary dataData under analysis

P1

P2≈3(P1)2

LNL results on 58Ni + 54Fe

Ec.m. (MeV)

Log slope

S-factor

Fus. x-sects.

A.M.Stefanini et al., PR C81, 037601 (2010)

Recent measurements on 40Ca+40Ca, 40Ca+48Ca and 48Ca+48Ca

have investigated fusion hindrance and nuclear structureeffects at sub-barrier energies

(Fusion-evaporation residues detected using the electrostatic beam deflector at LNL)

G.Montagnoli et al., PRC 85, 024607 (2012)C.L.Jiang et al., PRC 82, 041601(R) (2010) A.M.Stefanini et al., PLB 679, 95 (2009)

Our recent results on 32S + 48Ca

the logarithmic derivative is rather lowand keeps increasing below the barrier

the barrier distribution isvery wide and showsan unusual shape

by coupling schematicallya Q>0 transfer channel,the data are well fit

• Study of nucleon-nucleon correlations (particle-vibration couplings, pairing vibrations, sub-barrier transfer) in binary reactions near the barrier

• Couplings effects and fusion hindrance far below the barrier – fusion cross sections in light heavy-ion systems

• Developments for Prisma: Prisma: the new scattering chamber with a a

second TOF arm for kinematic coincidences, a new PPAC for light second TOF arm for kinematic coincidences, a new PPAC for light

heavy-ions, better tracking of ion trajectories for higher A heavy-ions, better tracking of ion trajectories for higher A

resolutionresolution

• Test of γ-particle coincidences in Galileo and of the EXOTIC set-up for very low fusion x-sects. measurements

• All this will allow us to use the future exotic SPES beams with great efficiency

• Study of nucleon-nucleon correlations (particle-vibration couplings, pairing vibrations, sub-barrier transfer) in binary reactions near the barrier

• Couplings effects and fusion hindrance far below the barrier – fusion cross sections in light heavy-ion systems

• Developments for Prisma: Prisma: the new scattering chamber with a a

second TOF arm for kinematic coincidences, a new PPAC for light second TOF arm for kinematic coincidences, a new PPAC for light

heavy-ions, better tracking of ion trajectories for higher A heavy-ions, better tracking of ion trajectories for higher A

resolutionresolution

• Test of γ-particle coincidences in Galileo and of the EXOTIC set-up for very low fusion x-sects. measurements

• All this will allow us to use the future exotic SPES beams with great efficiency

PRISMA-FIDES

Detection of coincident fragments (MCP,TOF,DE-E)

beam

PRISMA

Via high resolution kinematic coincidence we can also deduce the fission probability of associated heavy partners, determined as function of Z,A (light partner) and Q-value of the reaction

Light partner : high Z,A resolution

Heavy partner : low Z,A resolution

L.Corradi et al, Phys.Rev.C66(2002)024606

Astrophysical S factors for several systemsmeasured in the last few years

Measurements of very low fusion cross sections need high efficiency and low background. Tests using the EXOTIC line and -particle coincidences with GALILEO are being considered

Fusion of medium-light systems

Spese ordinarie

II braccio Prisma (coinc. cinem.)

Coinc. γ-particelle(in Galileo)

Miglior. tracking

Investimenti

Previsioni di spesa 2013 - PD

• Inventariabile: 56 k€• Consumo: 26 k€• Missioni estere: 6 k€• Missioni interne: 5 k€ TOTALE : 93 k€

(per tutta la collaborazione circa 189 k€)

Richieste ai servizi LNL per il 2013Servizio Lavoro richiesto Tempo

(mesi uomo)

Officina meccanica Completamento camera sliding seal, installazione e allineamentiInstallazione II braccio

6

1

Servizio Utenti(Supporto App. Sperim.)

Sviluppo, install. e collaudo del controllo PLC del vuoto PisoloUpgrading controllo x II braccio

3

1

Richieste ai servizi Padova per il 2013Servizio Lavoro richiesto Tempo

(mesi uomo)

Ufficio Tecnico 2 flangie di adattamentoSliding seal per secondo braccioe alloggiamento rivelatori γ LaBr3

2

Officina Meccanica Completamento camera sliding seal, installazione e allineamenti

6

Laboratorio Elettronica Ottimizzazione fast ampl. + HV per i due PPAC

2

Sliding-seal scattering chamber

Beam line

Prisma

Secondo Braccio

Target

End

04/10/23 PAC-meeting 2008 20

Electrostatic separatorElectrostatic separator and E- and E-ΔE-ToF telescope to detectToF telescope to detect evaporation residues at ≈ Oevaporation residues at ≈ Ooo

beam

E-ΔE-ToF telescope detecting ER

MCP, IC & Si detectorsscattering chamber

+ +

_ _

HV

HV

target

Very different behaviors

Milestones PRISMA-2 2011-2012

1) July 31, 2011 to conclude the experimental campaign of PRISMA-AGATA measurements → AGATA stayed at LNL until December 2011- milestone reached 100%

2) December 15, 2011 to organize a measurement of sub-barrier transfer reactions involving superfluid nuclei → milestone reached 100%

3) June 30, 2012 to perform the sub-barrier fusion experiment on Ca+Zr systems → milestone reached 80%

4) June 30, 2012 to complete the installation of the new scattering chamber for PRISMA → milestone reached 30%

5) June 30, 2012 to define the scientific program using PRISMA and Pisolo spectrometers for the next few years → milestone reached 100%

6) December 30, 2012 to complete the R&D studies of PRISMA upgradings for the next few years

Milestones PRISMA-FIDES 2013

1) July 31, 2013 to extend the sub-barrier fusion experiments to medium-light systems

1) July 31, 2013 to study sub-barrier transfer in 92Mo+54Fe or in another proton-rich system

2) .Sep. 30, 2013 to install and test the new gas pumping and vacuum control of PISOLO

1) Dec. 20, 2013 to measure nucleon transfer channels in Ca+Ca systems

1) Dec. 20, 2013 to complete the tests of new detectors and DAQ upgrading for the second arm of PRISMA

New sliding seal scattering chamberNew sliding seal scattering chamber

New large angle «coincidence arm»New large angle «coincidence arm»

EFB

EFB

MCP + PPAC + IC?

Sub-barrier transfer for 96Zr (beam) + 40Ca

L.Corradi et al., Phys. Rev. C84, 034603 (2011)