G.Raciti –Dip. Fisica& Astronomia –Univ. Catania & INFN – Otranto 2005 FASCI RADIOATTIVI (Esotici) Particelle o ioni instabili prodotti artificialmente(

Presentazione sul tema: "G.Raciti –Dip. Fisica& Astronomia –Univ. Catania & INFN – Otranto 2005 FASCI RADIOATTIVI (Esotici) Particelle o ioni instabili prodotti artificialmente("— Transcript della presentazione:

1 G.Raciti –Dip. Fisica& Astronomia –Univ. Catania & INFN – Otranto 2005 FASCI RADIOATTIVI (Esotici) Particelle o ioni instabili prodotti artificialmente( ovvero non esistenti in natura) con caratteristiche energetiche e spaziali tali da poter essere riutilizzati come un normale fascio ottenuto da un acceleratore. (10 -10 sec) (10 -10 sec) 10 -10 sec) 10 -10 sec) Li 11 (neutron rich) Li 11 (neutron rich) Sn 107 (proton-rich) Sn 107 (proton-rich)

2 Normal Nucleus: 6 neutrons 6 protons (carbon) 12 C Stable, found in nature Exotic Nucleus: 16 neutrons 6 protons (carbon) 22 C Radioactive, at the limit of nuclear binding Characteristics of exotic nuclei: Excess of neutrons or protons, short half-life, neutron or proton dominated surface, low binding What is an exotic nucleus?

3 284 isotopes with T 1/2 > 10 9 year Our beams till 1989 ! Un po di Storia…

4 <1940 495 Un po di Storia…

5 <1940 1940 495 822 Reactors: n on U Un po di Storia…

6 <1940 1940 1950 495 822 1244 First Isotope Separator experiment Niels Bohr Institute 1951 fast n on U: Kr and Rb isotopes Un po di Storia…

7 <1940 1940 1950 1960 495 822 1244 1515 Selective detection method: decay Un po di Storia…

8 <1940 1940 1950 1960 1970 495 822 1244 1515 2010 Light-ion induced spallation Heavy-ion induced fusion Un po di Storia…

9 <1940 1940 1950 1960 1970 1980 495 822 1244 1515 2010 2270 Projectile and target fragmentation Un po di Storia…

10 Stable + decay - decay decay p decay spontaneous fission Around 3000 of the expected 6000 nuclei have been observed Oggi

11 Produzione N prod = N inc N targ N prod = N inc N targ [ions/sec] [ions/sec] [nucl/cm 2 ] [cm 2 ] [ions/sec] [ions/sec] [nucl/cm 2 ] [cm 2 ] I(eA) N A [gr/cm 2 ] [cm 2 ] I(eA) N A [gr/cm 2 ] [cm 2 ] Z proj e [coul] A targ [gr] N prod = I(enA) 10 -9 10 19 6.02 10 23 [ gr/cm 2 ] 10 -6 [mbarn ] 10 -27 Z proj 1.602 A targ N prod = 3.76 I(enA) [ gr/cm 2 ] [mbarn ] Z proj A targ Z proj A targ N prod = [ gr/cm 2 ] = [gr/ cm 3 ] t [ m] 10 2 [ gr/cm 2 ] = [gr/ cm 3 ] t [ m] 10 2

12 Qualche calcolo….. I= 10enA -> 0.6 10 11 protons/sec Potenza (W)= I V = I (Energy/Charge state) Es: I=1mA E=50 A MeV di O 16 completamente strippato (O 8+) : P = 1 10 -3 (50 16/8) 10 6 =100 kW

13 ProductionTarget Un Esempio…...Produzione

14 ProductionTarget 1 hour 1 min =1mbarn =0.5 barn =1barn …..Reazione

15 Intensità Minime di RIBs

16 Reazioni di Produzione Bassa Energia (Fusione, Fissione, Reazioni dirette, Deep Inelastic)Bassa Energia (Fusione, Fissione, Reazioni dirette, Deep Inelastic) Alta Energia (Frammentazione Proiettile o Targhetta, Spallation, Fissione in volo)Alta Energia (Frammentazione Proiettile o Targhetta, Spallation, Fissione in volo) - peripheral elastic and quasi-elastic ( QE ) collisions - semi-peripheral deep-inelastic collisions ( DIT ) collisions - incomplete ( ICF ) and complete ( CF ) fusion in central collisions - pre-equilibrium emision typically preceding ICF/CF and DIT l ) l (angular momentum

17 Reazioni di Produzione Transfer Reactions In generale: In generale: Piccate ad angoli in avantiPiccate ad angoli in avanti 10 -1 – 10 mbarn 10 -1 – 10 mbarn

18 292 MeV 54 Fe + 92 Mo 146 Er(p4n) 141 Ho 402 MeV 78 Kr + 58 Ni 136 Gd(p4n) 131 Eu A.A. Sonzogni et al., Phys. Rev. Lett. 83 1116 (1999) D. Seweryniak et al., Phys. Rev. Lett. 86 1458 (2001) Reazioni di Produzione Fusione

19 Reazioni di Produzione Frammentazione del Proiettile Participant-spectator reactions at relativistic energies ( above 100 AMeV )

20 Reazioni di Produzione (Frammentazione)

21 Reazioni di Produzione Frammentazione della Targhetta Random removal of protons and neutrons from heavy target nuclei by energetic light projectiles (pre-equilibrium and equilibrium emissions).Spallation

22 Reazioni di Produzione

23 Reazioni di Produzione (Frammentazione Fissione)

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25 Reazioni di Produzione Fissione K.H. Schmidt et al., Model predictions of the fission-product yields for 238 U (2001)

26 Optimum delle Reazioni di Produzione

27 Metodi di Produzione In-Flight (Fascio prodotto direttamente nella reazione)In-Flight (Fascio prodotto direttamente nella reazione) Reazioni su targhette spesse ISOL (Prodotti di reazione accelerati in un secondo acceleratore)ISOL (Prodotti di reazione accelerati in un secondo acceleratore) DegradersDegraders TaggingTagging In Flight Acceleratore Primario (Driver) Target di Produzione Selezionatore e.m. Utente ISOL Acceleratore Primario (Driver) Target di Produzione Selezionatore e.m. Utente Acceleratore

28 RIBs Facilities nel mondo

29 RIBs Facilities in Europa CRC, Louvain-la-Neuve, Belgium delivering ISOL beams since 1989 SPIRAL, Caen, France delivering IF beams since 1984 delivering ISOL beams since 2001 REX-ISOLDE, Geneva, Switzerland delivering ISOL beams since 2001 GSI, Darmstadt, Germany delivering IF beams since 1990 MAFF, Munich, Germany under construction SPES, Legnaro, Italy project LNS-Catania-Italy EXCYT: ISOL Under commissioning FRIBS: IF since 2001

30 Production Yield I = N 1 2 3 4 5 cross-section, : primary-beam intensity, N: target thickness, 1 : product release and transfer efficiency, 2 : ion-source efficiency, 3 : efficiency due to radioactive decay losses, 4 : efficiency of the spectrometer, 5 : post-accelerator efficiency. N = Luminosity I = Intensità particelle prodotte

31 driver accelerator or reactor thin target high-temperature thick target fragment separator experiment detectors spectrometers... ion source mass separator storage ring In Flight (IF)Isotope Separator On Line (ISOL) heavy ions -fusion -fragmentation light and heavy ions, n, e -spallation -fission -fusion -fragmentation post accelerator 30 A MeV-GeV eventually slowed down s meV to 100 MeV/u ms to several s good beam quality gas cell ~ ms Confronto fra i due Metodi

32 Metodo ISOL IsotopesSeparationOnLine Driver ad alta intensità (Dissipazione Calore) Targhette di produzione (Raffreddamento e Radioattività) Efficienza Selezione(20%) Efficienza di estrazione (30%) Efficienza di Trasmissione alla Sorgente(30%) Potenza (W)= I V = I (Energy/Charge state) Es: I=1mA E=50 A MeV di O 16 completamente strippato (O 8+) : P = 1 10 -3 (50 16/8) 10 6 =100 kW Beam

33 Metodo ISOL Ottima qualità dei Fasci

34 secondary = production N target beam x release – transport x ionization x transport - storage - post-acceleration I secondary /I total Intensity Purity Event rate I counts (reaction) = I secondary branching reaction x N secondary target x spectrometer x detector I counts (decay) = I secondary branching x detector Peak to background R resolving power (suppression of background, identification of events) Figure di Merito

35 ISOL Running Facilities LocationYearDriver Post Accelerator CRC, Louvain-la- Neuve, Belgium 1989Cyclotron p, 30 MeV, 200 A cyclotrons K = 44 and 110 SPIRAL, GANIL, Caen, France 20012 cyclotrons heavy ions up to 95 MeV/u 6 kW cyclotron K = 265 2 - 25 MeV/u REX-ISOLDE, CERN, Geneva, Switzerland 2001PS booster p, 1.4 GeV, 2 A linac 0.8 - 2.2 MeV/u HRIBF, Oak Ridge, USA 1998cyclotron p, d,, 50 -100 MeV 10 - 20 A 25 MV tandem ISAC, TRIUMF, Vancouver, Canada 2000synchrotron p, 500 MeV, 100 A linac 1.5 MeV/u

36 GANIL

37 GANIL-SPIRAL(ISOL)

38 SPIRAL II

39 Louvain la Neuve (Belgio)

40 Louvain la Neuve

41 ISOLDE -CERN

42 Metodo In-Flight Separazione ElettroMagnetica (Coktail di RIBS) Uso di Degrader Accettanza in angolo solido del FRS RIBs non monoenergetici Energia ? Energia incidente NON REGOLABILE Rese di Produzione più alte Intensità di corrente 10 3 piu basse Relativi problemi di radioattività RIBs con vite medie piccole (< sec)

43 Overview of the Fragment Separation Technique Degrader Q 1 Q 2 Q 3 Q 4 Q 5 Q 6 Q 7 Q 8 Q 9 Dipole 1 Dipole 2 Production Target Final Focus Intermediate Focus

44 RIBs IF-Running Facilities In Flight GANIL NSCL-MSU GSI RIKEN DUBNA LANZHOU LNS C Cycl. C Cycl.s SIS Cycl. C Cycl.s Cycl. SISSI+LISE A1200 FRS or ESR RIPS ACCULINNA&COMBAS RIBLL FRS-CT <95 A MeV <200 A MeV <1.2 A GeV <150 A MeV <100 A MeV <80 A MeV <50 A MeV Laboratory Accelerators RIB Separator RIB Energies Fragment Separators

45 Magnetic rigidity The force qvB on a charged particle moving with velocity v in a dipole field of strength B is equal to its mass multiplied by its acceleration towards the centre of its circular path. Curvature radius which can be written as: B is called magnetic rigidity If we put in all the correct units we get: B = 33.356·p [KG·m] or: B = 3.3356·p [T·m] (if p is in [GeV/c])

46 Magnetic Dipole (I) A dipole is the ion-optical equivalent of a prism A dipole introduce dispersion, i.e. a relation between momentum and position A/q selection with a certain acceptance in momentun width Reference momentum Reference trajectory DIPOLE SELECTION

47 Magnetic dipole (II) Here we consider two different types of dipoles, represented by two examples: ALADIN:: A Large Acceptance DIpole magNet dipole magnet of the FRS (Fragment Recoil Separator) ALADIN: to evaluate the velocity of a fixed charged particle (momentum reconstraction): once B is know by the measurement of the trajectory of the ion, the evaluation of the velocity can be done if the A/Z of the charged particle is already known. Large acceptance in angle and momentum FRS dipole: Magnetic selection in mass, charge state and speed. Limited acceptance in angle and momentum Only particles with a limited range of bending radii, centered around 0, can pass. The binding radius 0 is defined by the geometry of the magnet.

48 Quadrupole (I) Magnetic field Hyperbolic contour x · y = constant A Quadrupole has 4 poles, 2 north and 2 south They are symmetrically arranged around the centre of the magnet There is no magnetic field along the central axis On the x-axis (horizontal) the field is vertical and given by: B y x On the y-axis (vertical) the field is horizontal and given by: B x y The field gradient, K is defined as:

49 Quadrupole (II) A pair of quadrupoles with a drift section in between is the ion-optical equivalent of a lens. Force on particles It focuses the beam horizontally and defocuses the beam vertically. Rotating this magnet by 90º will give a vertical focusing and an horizontal defocusing

50 Located in an intermediate focal plane on the beam line Better separation of isotopes with the same A/q ratio Reduction of contaminants The relative energy loss in the degrader is given by: With K: constant typical of the degrader A: nucleus mass e: thickness of the degrader Z: atomic number Degrader Thickness and material is chosen as a compromise between desired and undesired effects. ENERGY STRAGGLING ANGULAR STRAGGLING NUCLEAR REACTIONS INTENSITY LOSS

51 Wien Filter For the selected nucleus the forces due to the two fields compensate each other: The other ions are deviated No p dispersion E B Large velocity Small velocity

52 Optical Coordinate System 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

53 Matrix optics(I) 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.

54 Matrix optics(II) For a static magnetic system with midplane symmetry: The motion along x and y can be decomposed NO MIXED TERM

55 Achromatic Fragment Separator(I) 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 WHAT WE WANT 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

56 Achromatic Fragment Separator (II) filter the nuclei with the same A/q ratio preserve the achromaticity of the separator WEDGE SHAPED Thicker degrader at the high velocity side Thinner degrader at the lower velocitity side

57 Achromatic Fragment Separator (III)

58 Fragment Separators LISE

59 LISE at Ganil LISE = Ligne d Ions Super Epluch é s (Super Stripped Ion Line) secondary beam dipole 1 wedge Wien filter target http://www.ganil.fr/lise/lise.html dipole 2

60 LISE-GANIL

61 GSI-Darmstad

62 FSR@GSI

63 FRS of GSI

64 ESR - GSI

65 NSCL-MSU- USA

66

67 Fribs In Flight Radioactive Ion Beams 2001-2003: RIBs Production with C(62 AMeV ), 40 Ar and 58 Ni (40 AMeV) and 20 Ne (45 MeV) on Be target. 2004-2005: Transmission trough the LNS beam lines and First Experiment (EXPERA) bersaglio secondario (ΔE,ToF) (x,y) (A,Z), E ione secondario Si-Strip 1616 Tagging FRIBs -LNS

68 RI-Beam factory: RIKEN European Separator On-Line Radioactive Nuclear Beam Facility GSI New Projects of RIBs Facilities

69 EURISOL Date: ??? Site: ???

70 RIA-USA Date: ??? Site: ???

71 RIA

72

73 FAIR-GSI 2003

74 FAIR-GSI

75

76 New FRS

77 Spectroscopy Facilities

78 New FRS Performances

79 New Storage/ Cooling Rings

80 Mass Measurements

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84 Mass Measurements:Why?

85 Pbar Production Target: Iridium 60mm thick Proton beam energy >29 GeV Antiprotons Beam

86 High Energy Storage Ring and Detector Concept L = 2·10 32 cm -2 s -1 ; p = 1.5 – 15 GeV/c PANDA

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88

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90 Very Neutron Rich Hypernuclei

91 Detection and identification of Rare Nuclei The end of Mendeleevs table: superheavies Measuring and predicting the limits of nuclear existence Explaining complex nuclei from basic constituents Doubly-magic nuclei and shell structure far from stability Nuclear structure, rp-process Nuclear size and shape, r-process The size of the nucleus: halos and skins Understanding the origin of elements Nucleosynthesis (rp-process, r-process) Lifetimes/ -decay studies Isospin dependence of the nuclear force Neutron stars Nuclear Calorimetry Testing the Standard Model Applications in materials and life sciences Radioisotopes for Medical Imaging Physics Interaction cross section Elastic and Inelastic scattering Charge exchange Knockout or Stripping reactions Heavy-ion collisions Giant dipole resonance Coulomb excitation (2+) Direct measurements.

92 Production of longer lived neutron rich isotopes Connection to newly synthesized elements New Elements

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96 19 B and 22 C are bound Shell Model Calculation

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98 16 Be is not bound No Evidence for 16 Be

99 H. Sakurai et al., Phys. Lett. 448B, 180 (1999) Search for 28 O / Existence of 31 F

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