Presentation is loading. Please wait.

Presentation is loading. Please wait.

Elisa Rapisarda Università degli Studi di Catania Dottorato di Ricerca in Fisica.

Similar presentations


Presentation on theme: "Elisa Rapisarda Università degli Studi di Catania Dottorato di Ricerca in Fisica."— Presentation transcript:

1

2 Elisa Rapisarda Università degli Studi di Catania Dottorato di Ricerca in Fisica

3 Limit of existence of nuclei (location of the drip-lines and charge boundary of the heaviest elements) Nuclear structure (halo nuclei, skins, new magic numbers) Investigation of the EOS dependence on the isospin Astrophysics (Nucleosintesi degli elementi pesanti, rp- process)

4

5 N prod = N inc N targ cross-section, N inc : primary-beam intensity, N tar : target thickness, 1 : product release and transfer efficiency, 2 : ion-source efficiency, 3 : efficiency of the spectrometer, 4 : efficiency due to radioactive decay losses, 5 : post-accelerator efficiency.

6 Production Target Q 1,2 Test Point at the final focus of the Fragment Separator Test Point in Ciclope EXCYT Production Target Fragment Separator Test Point at the 20° line 27 Al (100 m) 58 Ni 40 AMeV 9 Be (500 m) 40 Ar 40 AMeV 12 C 62 AMeV 20 Ne 45 AMeV

7 Degrader Q 1 Q 2 Q 3 Q 4 Q 5 Q 6 Q 7 Q 8 Q 9 D1D1 D2D2 Bersaglio di prod. Bersaglio di produzione Q 1,2

8 filter the nuclei of interest from other fragment collect as much as possible the nuclei of interest Produce an achromatic image of the primary beam spot for further transport through other beam lines ACHROMATIC: the total dispersion is zero WHAT WE WANT HOW TO DO IT 2 optical section (a,b) symmetric to each other The optic of the second section merely compensate the dispersion caused by the first One-to-one image of the beam on target can be obtained at the final focus B = P/q

9 filter the nuclei with the same A/q ratio for fully stripped ions: A 2.5 /Z 1.5 preserve the achromaticity of the separator WEDGE SHAPED Thicker degrader at the high velocity side Thinner degrader at the lower velocitity side BUT: the spectrometer can not separate nuclei with the same ratio A/q DEGRADER dE/dx Z 2 /v 2

10

11 ü TAGGING: the basic idea is to identify event- by-event the produced ions with minor modifications of their characteristics: Charge and mass identification (Z,A) Position Diagnostic (x,y) Energy E measurements ü production yields MEASUREMENT ü TRANSMISSION measurements up to experimental areas 12 C + 9 Be(500 m) a 62 AMeV (February 2001) 40 Ar + 9 Be(500 m) a 40 AMeV (June 2002) 58 Ni + 27 Al(100 m) a 40 AMeV (June 2002) 20 Ne + 9 Be(500 m) a 45 AMeV (June 2004) Possible with pulsed beams: 10 6 ions/sec are distributed as one per burst at 100 MHz (10 nsec) LNS-CS RF MHz

12 Secondary Target (ΔE,ToF) (x,y) (x,y) Si PPACPPAC (A,Z), E Secondary Ion (ΔE,ToF) Si-Strip 1616 OR Plastic Scintillator 2.5x2.5cm 2 (rate: >10 5 ) Si(300μm) 3x3cm 2 (rate: >10 5 ) PPAC 4x4cm 2 (rate:10 4 ) ENERGY DIRECTION INTENSITY ION CHARACTERISTICS MODIFICATIONS energy loss straggling reactions PERFORMANCE: up to Z=70 for intermediate energy primary beam (30-40 MeV/u) RESOLUTION: 0.6 %

13 E Si (MeV) ToF (nsec) E plas (ch) 40 9 ZOOM E – E E – ToF

14 E plas (channel) 57 Ni 54 Co 56 Co 55 Co 52 Fe 53 Fe 54 Fe 55 Fe 51 Mn 53 Mn 52 Mn 50 Mn 54 Mn 49 Cr 51 Cr 50 Cr 48 Cr 52 Cr 48 V 49 V 50 V 47 V 47 Ti 46 Ti 46 V 45 Ti 44 Ti 43 Sc 43 Ca 42 Ca 39 K 38 Ar 41 K 40 K 42 K 39 Ar 40 Ar 41 Ca 36 Ar 37 Ar 40 Ca 38 K 37 Cl 44 Sc 45 Sc ToF(nsec) E Si (MeV) E – E E – ToF 58 Ni AMeV

15 To calculate the transmission and yields of fragments produced and collected in a spectrometer (*) (*) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A482(2002) 314 O.B.Tarasov, D.Bazin, M.Lewitowicz, O.Sorlin, Nuclear Physics A701(2002) Ottica magnetica del fragment separator Spessore dei vari materiali (degrader, rivelatori, etc.) Rigidità magnetica Bρ dello ione scelto INPUT Matrici di trasporto Rese isotopiche Matrici ΔE-ToF, ΔE-E Spettri E, ΔE, x, y OUTPUT Sezioni durto: 1.Param. EPAX 2.Valori sperimentali OPZIONI

16 E(MeV) ToF(nsec) 40 Ar+ 9 40AMeV ΔE-ToF Lise ΔE-ToF experimental

17 0.8AMeV 23AMeV experimental 39 Cl 23AMeV Energy(AMeV) 40 Ar+ 9 Be 40AMeV ΔE/E=3% Lise simulation 1.5 AMeV 21.2 AMeV 56 Co 21.7AMeV Energy(AMeV) 58 Ni+ 27 Al 40AMeV experimental Lise simulation ΔE/E=7%

18 for 20 Ne+ 9 Be 45AMeV E (MeV) 18 Ne with 27 Al 200μm degrader SECONDARY REACTIONS ANGULAR AND ENERGETIC STRAGGLING Better separation for isotopes with the same A/Z Riductions of contaminants (*) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A482(2002) 314 O.B.Tarasov, D.Bazin, M.Lewitowicz, O.Sorlin, Nuclear Physics A701(2002) E (MeV) No degrader 18 Ne (*)

19 20 Na 19 Ne 18 Ne Bρ=1.58 Tm 20 Na 19 Ne Bρ=1.57 Tm 20 Na 19 Ne 18 Ne 17 Ne 17 F 16 F 15 O 14 O Bρ=1.63 Tm 20 Na 19 Ne 18 Ne 17 Ne 15 O Bρ=1.61 Tm 17 Ne 15 O 14 O Bρ=1.64 Tm 21 Na 20 Na 20 Ne 19 Ne 18 Ne 17 Ne 18 F 17 F 16 F 16 O 15 O 14 O 14 N 13 N 12 N 12 C 11 C 10 C 10 B 9B9B No degr 20 Ne+ 9 45AMeV

20 C+Be ioni/sec Ar+Be ioni/sec Ni+Al ioni/sec 12 N61.2 ± 3 39 Cl237 ± 7 55 Co259 ± 6 10 C29.0 ± 2 36 S95.8 ± 3 53 Fe97 ± 4 8B8B8.8 ± 1 34 P43 ± 2 54 Fe54 ± 3 31 Si22 ± 1 53 Mn49 ± 3 Gaussian Fits to obtain the yields I = 100 epA Primary intensity 100 enA (*10 3 ) 10 5 ioni/sec Ne+Be ioni/sec 21 Na 16.5 ± 4 18 Ne 10.8 ± 3 15O15O 16.2 ± 4 13 N 5.3 ± 2 I = 10 enA Cross-Comparison with LISE 20 Ne+ 9 Be 45AMeV

21 Rate (ioni/sec) massa 12 C+ 9 Be 62AMeV 40 Ar+ 9 Be 40AMeV 58 Ni+ 27 Al 40AMeV i=3enA i=7enA i= 100epA

22 very good transmission efficiency up to 20 degrees cave feasibility of experiments with such RIBs Transmission % 20 Ne+ 9 Be 45AMeV 21 Na 20 Ne 19 Ne 18 Ne Ciclope beam line 20 degrees beam line OPTICAL TRANSPORT by using pilot beam STABLE BEAM PROPERLY DEGRADED

23 Study of FRAGMENTATION CROSS SECTIONS of RIBs on a Carbon target 208 Pb 18 Ne 18 Ne* 16 O 2 He 208 Pb 18 Ne 18 Ne* 16 O Search for DI- PROTON DECAY of excited states of 18 Ne

24

25 22 Na 21 Na 21 Ne 20 Ne 19 Ne 18 Ne 19 F 18 F 17 F 16 O 15 O 15 N 14 N 13 C 13 N 12 C 11 C 11 B 17 O Secondary Target (ΔE,ToF) (x,y) (A,Z), E Secondary Ion Si-Strip 1616 Tagged Ion Si-Strip X-Y Position measured in the 20° line

26 89 THREE-FOLD TELESCOPES ARRAY 4.5° 16.5° 81 TWO-FOLD TELESCOPES ARRAY 4.5° 4.5°

27 EVENT DISPLAY: Three body event with Carbon Target EVENT DISPLAY Three body event with Carbon Target

28 21 Na 21 Ne 20 Ne 19 Ne 18 Ne 18 F 17 F 16 O 15 O 14 N 13 C 12 C 11 C 11 B

29 21 Na selected on all the strips Extra-production of C and O to be better investigated! Cross – Section of products from 21 Na + C

30 Proton rich with 58 Ni+ 27 Al and 20 Ne+ 9 Be Neutron rich with 40 Ar+ 9 Be Light proton rich with 12 C+ 9 Be Measured yields are in good agreement with LISE simulation Ions tagging is possible Optimized transmission of the RIBs up to some experimental area Experiments already started

31 Eliminazione RF (Plastico / PPAC) Sostituzione elementi magnetici (quadrupoli) Tracciatura eventi

32 208 Pb 18 Ne 18 Ne* 16 O 208 Pb 18 Ne 18 Ne* 16 O 2 He Sezione durto dellordine di 100 mbarn (Eccitazione Coulombiana) Branching ratio di circa * *

33 1 hour 1 min = 1 mbarn =0.5 barn =1 barn Primary Beam Current (enA) Time (sec) 41 Cl (target=5mg/cm 2, Production target 500 m) 40 Cl Induced Reaction for Target Thickness=5mgr/cm 2 and =1barn Reaction Products Rate (event/sec) Primary Beam Current (enA)

34 Estimated minimum beam intensities for various experiments with fast fragmentation Estimated beam intensities for various experiments with fast fragmentation RIA

35 Spettro Y Lise Spettro X-Y PPAC Matrice X-Y Si-Strip Si-Strip 16X16 (300μm) 50x50mm 2

36 ToF (nsec) E Si (MeV) C 12 +Be 9 (500um) 62 AMeV settings on 11 C NoDegrader 12 9 C 12 +Be 9 (500um) 62 AMeV Bp= E – ToF sperimentale E – ToF LISE

37 FRIBs Test point Ciclope Test Point

38 CFD Fast. Amp Lin. Amp X left X right Y up Y down PPACPPAC Si Plastic RF AND ADC E GATEGATE TDC S T A R T COMMONSTOPCOMMONSTOP

39 Spettri in energia del rivelatore a Si E (MeV) Counts Spettro α

40 1.La terna di quadrupoli Q 1 -Q 3 focalizza i frammenti nel dipolo D 1 2.D 1 effettua la prima selezione in Bρ 3.La terna di quadrupoli Q 4 -Q 6 crea il fuoco intermedio 4.Un degrader (opzionale) causare una perdita di energia Z 2 5.I quadrupoli Q 7 -Q 9 creano il fuoco finale acromatico, in cui la posizione degli ioni è indipendente dal loro impulso 6.D 2 effettua una seconda selezione in p/q. Degrader Q 1 Q 2 Q 3 Q 4 Q 5 Q 6 Q 7 Q 8 Q 9 D1D1 D2D2 Bersaglio di produzione selezione A/Z dE/dx Z 2

41 Laboratorio Acceleratore Frag. Sep. Energie (AMeV) GANIL RIKEN GANIL GSI NSCL -MSU LANZHOU Ciclotroni SIS Ciclotrone Ciclotroni Ciclotrone SISSI + LISE A1200 FRS o ESR RIPS ACCULINNA&COMBAS RIBLL <95 <200 <1200 <150 <100 <80 Laboratorio Accel. Primario Post-acceler. Energie Ciclotrone Ciclotroni PS Booster Sincrotrone Ciclotrone Louvain le Neuve SPIRAL-GANIL ISOLDE-CERN TRIUMF -Vancouver ORNL Oak Ridge ANL - Argogne Ciclotrone K110 CIME LINAC TANDEM ATLAS AMeV 2-25 AMeV <2.2 AMeV AMeV 25 MVolt 6-15 AMeV..extended evalution of fundamental nuclear properties(massa data e charge radius data

42 Calcolo di trasmissione e rese di frammenti e residui di fusione prodotti e raccolti da un Fragment Separator (*) ToF(nsec) E(MeV) (*) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A482(2002) 314 O.B.Tarasov, D.Bazin, M.Lewitowicz, O.Sorlin, Nuclear Physics A701(2002)

43 Emittance = 20 p mm mr Solid Angle = 0.32 msr Br max = 18 Tm Dp / p = 2% Resolving Power = 1600 at Middle Focus Achromatic at Final Focus Primary Beam from SIS B – E – B Technique

44 INTENSITA ~ 10 ioni/sec TARGET SECONDARI SPESSI ~ 500mg/cm 2

45 Progetto LNS: EXCYT (1994) (CS+TANDEM) FRIBs (CS+FRS),LNS

46 Electrods Thickness 300m

47 The coordinates of each particle are defined in term of the reference particle We need 6 variables to characterize the particle in the phase-space: (ion-optics convention on phase space) x,y are positions or displacement from the central orbit x,y are angles with respect to the central orbit l is the path length difference is the fractional momentum deviation from the assumed central trajectory ds x x dx x s Central orbit xs plane Vertical Horizontal Longitudinal

48 The charge particle motion can be reduced to a process of matrix multiplication The action of a magnet on the particle coordinates is represented by a 6 6 matrix The 6 variables are component of a vector Each magnetic element has its own characteristic matrix TRANSFER MATRIX The transfer matrix for a succession of magnet is the product of the transfer matrix for individual elements.

49 For a static magnetic system with midplane symmetry: The motion along x and y can be decomposed NO MIXED TERM

50 ΔE-ToF experimental 22 Na 21 Na 21 Ne 20 Ne 19 Ne 18 Ne 19 F 18 F 17 F 16 O 15 O 15 N 14 N 13 C 13 N 12 C 11 C 11 B 17 O 20 Ne+ 9 45AMeV ΔE-ToF (experimental) ΔE-ToF (LISE)

51 Q7Q7 Q 4,5,6 Q8Q8 Q9Q9 D2D2 Degrader Q 1 Q 2 Q 3 Q 4 Q 5 Q 6 Q 7 Q 8 Q 9 D1D1 D2D2 Prod. Target Fragment Separator Production Target Q 1,2 27 Al (100 m) 58 Ni 40 AMeV 9 Be (500 m) 40 Ar 40 AMeV 12 C 62 AMeV 20 Ne 45 AMeV

52 Sezioni durto di frammentazione di 129 Xe in un bersaglio di 27 Al a 800AMeV. Linea tratteggiata EPAX 1, linea continua EPAX 2. INDIPENDENTE DALLENERGIA nel centro di massa (limiting fragmentation) NON DESCRIVE la frammentazione di PROIETTILI FISSILI e reazioni di PICK-UP per frammenti con A~A p DISTRIBUZIONE ISOTOPICA centrata su N/Z del proiettile e con varianza Δ piccola. Fragments far away from the projectile (ΔA>15-20%) DISTRIBUZIONE ISOTOPICA INDIPENDENTE DAL PROIETTILE, posizione, forma ed ampiezza dipendenti solo da A f (statisical evaporation from an excited pre-fragment) PARAMETRIZZAZIONE delle sezioni durto di frammentazione CARATTERISTICHE

53 Total cross section of elements with mass A f it accounts for the peripheral nature of the reaction Pendenza della resa in massa Carica più probabile CHARGE DISPERSION ISOBARIC CROSS SECTION * * (*) K. Summerer et al. Phys. Rev. C42, 2546 (1990) Phys. Rev. C52, 1106 (1995)


Download ppt "Elisa Rapisarda Università degli Studi di Catania Dottorato di Ricerca in Fisica."

Similar presentations


Ads by Google