Laboratori Nazionali del Sud

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Accelerators

Fribs@lns

THE FRAGMENT SEPARATOR

The FRIBs@LNS (in Flight Radioactive Ion Beams at LNS) facility at LNS, Catania produces RIBs at intermediate energy by using the In-Flight fragmentation technique. Exotic beams, from 6He to 68Ni, have been produced since 2001 following the pioneering work of G.Raciti [1], using  fragmentation of various stable beams accelerated by the LNS Superconducting Cyclotron. One of the most important characteristics of the fragment separator is that it is based on the use of the magnets of the transport beam line, therefore the beam can be used, in principle, in any of the LNS experimental halls. The configuration file for LISE code can be download here. The list of produced beams is available here.

TAGGING SYSTEM

The fragmentation beam is a cocktail beam that needs to be identified event by event in order to be used for real experiments [1]. An advanced device [2] is now used in the CHIMERA beam line consisting of a large surface MCP detector producing the start of TOF measurements, a DSSSD thin detector able to generate the energy loss information, position and the stop of TOF, a PPAC position sensitive detector to complete the trajectory measurement. Photos and examples of identification scatter plots are available here.

RESULTS

A list of publications and experiments performed with LNS fragmentation beams is available here. The first important result was the study of the DIPROTON decay of the 6.18 excited level of 18Ne [3]. After this pilot experiment performed in the 20° beam line with the HODO detector, many tests and real experiments were performed in the CHIMERA beam line. Angular distributions of neutron transfer reactions were obtained with the kinematical coincidence method [4]. One of the most interesting and recently published results was the study of alpha cluster levels of 10Be with the first observation of a level at 13.1 MeV proposed as the 6+ member of the rotational band based on the second 0+ state at 6.137 MeV [5]. The last experiment performed during 2015 was the search of the PYGMY resonance excitation with isoscalar probe on 68Ni.

PERSPECTIVES

The upgrade project of the superconducting cyclotron opens new perspectives to the use of fragmentation beams at LNS. The expected availability of a primary beam intensity up to 10 kW can be used to produce very intense and very exotic fragmentation beams. Obviously an important upgrade of the production target, of the tagging system and of the whole layout is necessary to fully profit of this intensity upgrade.  The project of a new fragment separator is going on. Radioprotection issues suggest to move the new fragment separator in a position different from the present one. The idea is to maintain the possibility to send the beam in the largest possible number of experimental points. 

The list of produced beams

 

primary beam

beam

intensity (kHz/100W)

18O 55MeV/A

16C

120

setting 11Be

17C

12

 

13B

80

 

11Be

20

 

10Be

60

 

8Li

20

18O 55MeV/A

14B

3

setting 12Be

12Be

5

 

9Li

6

 

6He

12

13C 55 MeV

11be

50

setting 11Be

12B

100

36Ar 42 MeV

37K

100

setting 34Ar

35Ar

70

 

36Ar

100

 

37Ar

25

 

33Cl

10

 

34Cl

50

 

35Cl

50

20Ne 35 MeV

18Ne

50

setting ne18

17F

20

 

21Na

100

70Zn 42MeV

 

 

setting 68Ni

68Ni

20

 Photo and examples of identification scatter plots are available here

REFERENCES

 

 [1] G. Raciti, E. Rapisarda , M. De Napoli , F. Amorini , L. Calabretta , G. Cardella ,G. Cosentino , C. Sfienti , V. Shchepunov.  Intermediate energies tagged RIBs NIM B 266 (2008) 4632

[2] I.Lombardo, F.Amorini, G.Cardella, S.Cavallaro, E.De Filippo, E.Geraci, L.Grassi, E.La Guidara, G.Lanzalone, A.Pagano, M.Papa, S.Pirrone, G.Politi, F.Porto, F.Rizzo, P.Russotto, G.Verde, M.Vigilante . Use of Large Surface MicroChannel Plates for the Tagging of Intermediate Energy Exotic Beams NIMB (Proc. Suppl.) 215 (2011) 272

[3] G.Raciti, G.Cardella, M.De Napoli, E. Rapisarda, F.Amorini, C.Sfienti. He-2 decay from the 18Ne 6.15 MeV (1-) excited state.  Phys. Rev. Lett. 100, 192503(2008)

 [4] L. Acosta , F. Amorini, L. Auditore, I. Berceanu, G. Cardella, M.B. Chatterjiee, E. De Filippo, L. Francalanza, R. Gianì, L. Grassi, A. Grzeszczuk , E. La Guidara, G. Lanzalone, I. Lombardo, D. Loria, T. Minniti, E.V. Pagano, M. Papa, S. Pirrone, G. Politi, A. Pop, F. Porto, F. Rizzo, E. Rosato, P. Russotto , S. Santoro, A. Trifirò, M. Trimarchi, G. Verde, M. Vigilante. Kinematical coincidence method in transfer reactions. NIMA A 715 (2013) 56

[5] D. Dell’Aquila, I. Lombardo, L. Acosta, R. Andolina, L. Auditore, G. Cardella, M. B. Chatterjiee, E. De Filippo, L. Francalanza, B. Gnoffo, G. Lanzalone, A. Pagano, E. V. Pagano, M. Papa, S. Pirrone, G. Politi, F. Porto, L. Quattrocchi, F. Rizzo, E. Rosato, P. Russotto, A. Trifirò, M. Trimarchi, G. Verde, and M. Vigilante. New experimental investigation of the structure of 10Be and 16C by means of intermediate-energy sequential breakup. PHYS.REV C 93, 024611 (2016).

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