The deep inelastic reaction 48Ca+64Ni at 6 MeV/A has been studied using the CLARA–PRISMA setup. Angular distributions for pure elastic scattering and total cross-sections of the most relevant transfer channels have been measured. The experimental results are compared with predictions from a semiclassical model, showing good agreement for the presently analyzed few neutrons transfer channels. The decay of the most intense reaction products has also been studied, giving indications of the population of states with very short lifetimes.Gadea Raga, Andrés, Gadea.Andres@ific.uv.e

A. Bracco

A. Corsi

A. Gadea

A. Maj

A. Zucchiatti

A.M. Stefanini

B. Million

B.Guiot

C. Ur

D. Bazzacco

D. Mengoni

D. Montanari

D.R.Napoli

E. Farnea

E. Fioretto

F. Camera

F. DellaVedova

F. Recchia

F. Scarlassara

F.C.L. Crespi

G. Benzoni

G. de Angelis

G. Lo Bianco

G. Montagnoli

G. Pollarolo

J.J.Valiente-Dobon

L. Corradi

M. Kmiecik

M. Pignanelli

N. Blasi

O. Wieland

P. Mason

R. Nicolini

R. Orlandi

R. Silvestri

R.P. Singh

S. Brambilla

S. Leoni

S. Lunardi

S. Szilner

S.M. Lenzi

W. Meczynski

The deep inelastic reaction 48Ca+64Ni at 6 MeV/A has been studied using the CLARA–PRISMA setup. Angular distributions for pure elastic scattering and total cross-sections of the most relevant transfer channels have been measured. The experimental results are compared with predictions from a semiclassical model, showing good agreement for the presently analyzed few neutrons transfer channels. The decay of the most intense reaction products has also been studied, giving indications of the population of states with very short lifetimes

Montanari, D.

Leoni, S.

Benzoni, G.

Blasi, N.

Bracco, A.

Brambilla, S.

Camera, F.

Corsi, A.

Crespi, F.

Million, B.

Nicolini, R.

Wieland, O.

Corradi, L.

De Angelis, G.

Della Vedova, F.

Fioretto, E.

Gadea Raga, Andrés

Guiot, B.

Napoli, D. R.

Orlandi, R.

Recchia, F.

Silvestri, R.

Stefanini, A. M.

Singh, R. P.

Szilner, S.

Valiente Dobón, J. J.

Bazzacco, D.

Farnea, E.

Lenzi, L. M.

Lunardi, S.

Mason, P.

Mengoni, D.

Montagnoli, G.

Scarlassara, F.

Ur, Calin A.

Lo Bianco, G.

Zucchiatti, A.

Kmiecik, M.

Maj, A.

Meczynski, W.

Pollarolo, G.

Repositori d'Objectes Digitals per a l'Ensenyament la Recerca i la Cultura

Vol. 40 (2009) ACTA PHYSICA POLONICA B No 3POPULATION OF NEUTRON-RICH NUCLEI AROUND48Ca WITH DEEP INELASTIC COLLISIONS∗D. Montanaria, S. Leonia, G. Benzonia, N. Blasia, A. BraccoaS. Brambillaa, F. Cameraa, A. Corsia, F.C.L. CrespiaB. Milliona, R. Nicolinia, O. Wielanda, L. CorradibG. de Angelisb, F. Della Vedovab, E. Fiorettob, A. Gadeab,cB. Guiotb, D.R. Napolib, R. Orlandib, F. RecchiabR. Silvestrib, A.M. Stefaninib, R.P. Singhb, S. Szilnerb,dJ.J. Valiente-Dobónb, D. Bazzaccoe, E. Farneae, S.M. LenzieS. Lunardie, P. Masone, D. Mengonie, G. MontagnolieF. Scarlassarae, C. Ure, G. Lo Biancof , A. ZucchiattigM. Kmiecikh, A. Majh, W. Meczynskih, G. PollaroloiaDipartimento di Fisica and INFN, Sezione di Milano, Milano, ItalybLaboratori Nazionali di Legnaro,Padova, ItalycIFIC, CSIC-University of Valencia, SpaindRBI, Zagreb, CroatiaeDipartimento di Fisica and INFN Sezione di Padova, Padova, ItalyfUniversità di Camerino and INFN Sezione di Perugia, Camerino (PG), ItalygINFN Sezione di Genova, Genova, ItalyhH. Niewodniczanski Institute of Nuclear Physics, PAN, Krakow, PolandiDipartimento di Fisca Teorica and INFN Sezione di Torino, Torino, Italy(Received November 20, 2008)The deep inelastic reaction 48Ca+64Ni at 6 MeV/A has been studiedusing the CLARA–PRISMA setup. Angular distributions for pure elasticscattering and total cross-sections of the most relevant transfer channelshave been measured. The experimental results are compared with predic-tions from a semiclassical model, showing good agreement for the presentlyanalyzed few neutrons transfer channels. The γ-decay of the most intensereaction products has also been studied, giving indications of the popula-tion of states with very short lifetimes.PACS numbers: 21.10.Re, 21.10.Gv, 25.85.Ge, 27.90.+b∗ Presented at the Zakopane Conference on Nuclear Physics, September 1–7, 2008,Zakopane, Poland.(585)586 D. Montanari et al.1. IntroductionOne of the most investigated issues in nuclear physics is the influenceof the N/Z ratio on the structure of the nucleus. Various models predictrelatively well properties for nuclei close to the valley of stability, while dis-agreement is found for more exotic systems. For this reason the fundamentalmodes of excitation, vibrations and rotations, are studied as a function ofN/Z. In a recent experiment we investigated the population and decay ofneutron-rich nuclei around 48Ca by means of deep-inelastic collisions (DIC)at energies ≈ 2.5 times above the Coulomb barrier. Neutron-rich Ca iso-topes are particularly interesting since highly excited states of E1 characterhave been measured in photon scattering experiments [1], being interpretedas pygmy dipole resonance states. We present here the results of a prelim-inary analysis of the angular distributions for pure elastic scattering andtotal cross-sections of the most relevant transfer channels. The data arecompared with the semiclassical multi-nucleon transfer model of Ref. [2]. Inaddition, a preliminary analysis of the γ-spectra is shown.2. Experimental setup and data analysisThe experiment was performed at Laboratori Nazionali di Legnaro, us-ing a 48Ca beam provided by the Tandem-Alpi accelerators at 270 MeV,impinging onto a 0.98 mg/cm2 thick 64Ni target. The reaction productswere detected by the magnetic spectrometer PRISMA and their γ-decay wasmeasured in coincidence by the CLARA Ge array [3]. PRISMA was placedat 20◦, which is the grazing angle for this reaction. Several atomic specieshave been populated, from −4p to +4p, and mass spectra corresponding tothe pick-up and stripping of several neutrons have been obtained.From a preliminary analysis of the data, angular distributions for pureelastic scattering and total cross-sections for the most relevant transfer chan-nels have been obtained. The elastic scattering cross-section of 48Ca has beenevaluated following the procedure described in Ref. [4] and is illustrated inFig. 1(a). The intensity of the pure elastic scattering has been determinedby subtracting from the total kinetic energy loss (TKEL) spectrum of 48Ca,measured in PRISMA (dashed line), a similar event distribution obtainedrequiring a γ-coincidence with the CLARA array (solid line), normalized inthe tail region. The resulting peak (shaded area) is centered around TKEL≈ 0 with a FWHM ≈ 2.5 MeV, which is consistent with the combined energyresolution of the 48Ca beam and of the experimental setup, as also reportedin Ref. [4]. By doing the subtraction in steps of 1 degree over the angular ac-ceptance of PRISMA (+14◦ < θ < +26◦), the elastic scattering distributionof 48Ca has been obtained, its ratio to the Rutherford cross-section comparedto the calculation by the GRAZING code (solid line) [2] is shown in the in-Population of Neutron-Rich Nuclei Around 48Ca with Deep Inelastic . . . 587set of Fig. 1(a). This ratio allows to obtain a normalization factor whichis used to estimate the total cross-sections (i.e. integrated in Q-values andsolid angle) for some of the most intense reaction products, assuming a bellshape angular distribution mostly covered by the acceptance of PRISMA.As shown in Fig. 1(b), good agreement is obtained with predictions fromGRAZING (histograms) for channels involving few nucleon transfer. Thiscan be interpreted as a dominant successive transfer mode over pair transferor other transfer mechanisms. On the other hand, larger discrepancies arefound in more exotic channels, which could be an indication of the presence,in these cases, of other reaction mechanisms not included in the model.Fig. 1. Panel (a): the TKEL distribution of 48Ca (angle-integrated) measured inPRISMA without coincidence with γ-rays (dashed line) and requiring a γ-coin-cidence in the Ge array (solid line). The difference spectrum (shaded area) givesthe pure elastic scattering contribution. The points in the inset give the ratio ofthe elastic peak to the Rutherford cross-section over the angular acceptance ofPRISMA, compared to the calculation by the GRAZING code [2]. Panels (b)–(e):experimental total cross-sections for some of the most intense transfer channels(symbols), compared to predictions by GRAZING (histograms).Fig. 2 shows examples of γ-spectra measured by the CLARA array incoincidence with 49Sc and 49Ca ions detected in PRISMA. Apart from thestrong peaks already observed in deep-inelastic heavy-ion reactions in thicktarget experiments at lower energies, i.e. around the Coulomb barrier [5],additional transitions are visible, previously observed in transfer reactionswith light ions only [6]. A similar pattern is found in other systems (47Ca and50Ca). This is mostly caused by the very short lifetimes of the correspondingstates which leads to in-flight emission of deexciting transitions.588 D. Montanari et al.Fig. 2. Gamma spectra of 49Ca (left) and 49Sc (right). The arrows indicate thetransitions which have been observed in reaction involving light ions only [6].3. ConclusionsPreliminary results from the experiment 48Ca + 64Ni at 6 MeV/A, per-formed with the CLARA-PRISMA setup, have been presented. They includecross-sections for the most intense transfer channels measured relatively tothe elastic scattering of 48Ca. A semiclassical model well reproduces thedata corresponding to (−1p) and (+1p) channels, while more massive trans-fer channels, presently under analysis, may involve additional contributionfrom pair transfer and evaporation modes. The γ-spectra display as sharplines also transitions from short-lived states, in contrary to thick target ex-periments.The work has been supported by the EU (Contract EURONS Nr. RII3-CT-2004-506065) and by the Polish Ministry of Science and Higher Educa-tion (Grant No. 1 P03B 030 030 and N N202 309135).REFERENCES[1] T. Hartmann et al., Phys. Rev. Lett. 93, 192501 (2004).[2] A. Winther, Nucl. Phys. A594, 203 (1995).[3] A. Gadea et al., Eur. Phys. J. A20, 193 (2004).[4] S. Szilner et al., Phys. Rev. C76, 024604 (2007).[5] R. Broda, J. Phys. G32, R151(2006).[6] Nucl. Data Sheets 109, 1879 (2008).

Population of neutron-rich nuclei around 48ca with deep inelastic collisions

B. Guiot

D. R. Napoli

A. M. Stefanini

R. P. Singh

J. J. Valiente Dobon

S. M. Lenzi

AIR Universita degli studi di Milano

POPULATION OF NEUTRON-RICH NUCLEI AROUND 48Ca WITH DEEP INELASTIC
COLLISIONS

The deep inelastic reaction 48Ca+64Ni at 6 MeV/A has been studied using the CLARA–PRISMA setup. Angular distributions for pure elastic scattering and total cross-sections of the most relevant transfer channels have been measured. The experimental results are compared with predictions from a semiclassical model, showing good agreement for the presently analyzed few neutrons transfer channels. The \gamma -decay of the most intense reaction products has also been studied, giving indications of the population of states with very short lifetimes

MONTANARI, DANIELE

DELLA VEDOVA, FRANCESCA

RECCHIA, FRANCESCO

LENZI, SILVIA MONICA

LUNARDI, SANTO

MENGONI, DANIELE

MONTAGNOLI, GIOVANNA

SCARLASSARA, FERNANDO

LEONI S

BENZONI G

BLASI N

BRACCO A

BRAMBILLA S

CAMERA F

CORSI A

CRESPI FCL

MILLION B

NICOLINI B

WIELAND O

CORRADI L

DE ANGELIS G

FIORETTO E

GADEA A

GUIOT B

NAPOLI DB

ORLANDI R

SILVESTRI R

STEFANINI AM

SINGH RP

SZILNER S

VALIENTE DOBON JJ

BAZZACCO D

FARNEA E

MASON P

UR C

LO BIANCO G

ZUCCHIATTI A

KMIECIK M

MAJ A

MECZYNSKI W

POLLAROLO G.

Archivio istituzionale della ricerca - Università di Padova

Population of Neutron-Rich Nuclei Around 48Ca with Deep Inelastic Collisions

The deep inelastic reaction 48Ca+64Ni at 6 MeV/A has been studied using the CLARA-PRISMA setup. Angular distributions for pure elastic scattering and total cross-sections of the most relevant transfer channels have been measured. The experimental results are compared with predictions from a semiclassical model, showing good agreement for the presently analyzed few neutrons transfer channels. The γ-decay of the most intense reaction products has also been studied, giving indications of the population of states with very short lifetimes

F. Crespi

G. d. Angelis

F. Vedova

A. c. Gadea

D. Napoli

A. Stefanini

R. Singh

S. d. Szilner

J. Valiente Dobón

G. L. Bianco

Population of neutron-rich nuclei around 48Ca with deep inelastic collisions

The reaction (48)Ca+(64)Ni has been studied in the deep inelastic regime at approximately 6 MeV/A, by the CLARA-PRISMA setup. Angular distributions of the reaction cross sections have been obtained for the most intense reaction products, taking into account the response function of the magnetic spectrometer. The response of PRISMA has been calculated making use of a MonteCarlo simulation of the transport of the ions in the spectrometer, starting from known events distributions. For the one-nucleon transfer channels, the experimental data are in good agreement with predictions from a semiclassical multi-nucleon transfer model

Population of neutron-rich nuclei around 48ca with deep inelastic collisions

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Repositori d'Objectes Digitals per a l'Ensenyament la Recerca i la Cultura

AIR Universita degli studi di Milano

Archivio istituzionale della ricerca - Università di Padova

Archivio istituzionale della ricerca - Università di Padova

Archivio istituzionale della ricerca - Università di Padova

AIR Universita degli studi di Milano