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PRISMA PRISMA SpectrometerSpectrometer
E. FiorettoINFN - LNL
Target
Beam
Rotating platform
Focal plane
Quadrupole
Start detector
30 cm
50 cm
Dipole60°
120 cm
-20°
+130°
INTAG meetingJanuary 27th, 2005 - Jyväskylä
Angular acceptances Δθ ~ ±6o Δφ ~ ±11o
Solid angle ΔΩ ~ 80 msr
Distance target-FPD 7 m
Energy acceptance ± 20%
Momentum acceptance ± 10%
Maximum rigidity ME/q2 = 70 MeV amu
Dispersion 4 cm/%
Energy resolution 1/1000 (via TOF)
Mass resolution 1/300 FWHM (via TOF)
Aberrations correction via software
Angular acceptances Δθ ~ ±6o Δφ ~ ±11o
Solid angle ΔΩ ~ 80 msr
Distance target-FPD 7 m
Energy acceptance ± 20%
Momentum acceptance ± 10%
Maximum rigidity ME/q2 = 70 MeV amu
Dispersion 4 cm/%
Energy resolution 1/1000 (via TOF)
Mass resolution 1/300 FWHM (via TOF)
Aberrations correction via software
E. FiorettoINFN - LNL
Design Characteristics of PRISMADesign Characteristics of PRISMA
INTAG meetingJanuary 27th, 2005 - Jyväskylä
The Start DetectorThe Start Detector
Developed in the collaboration: INFNDeveloped in the collaboration: INFN--PadovaPadova, , JINR JINR DubnaDubna, INFN, INFN--LNL LNL
The readout of the anode is based on two The readout of the anode is based on two orthogonal delay lines.orthogonal delay lines.The delay lines are homeThe delay lines are home--made using 70 made using 70 µµm m diameter Cudiameter Cu--Be wires.Be wires.Timing Timing resolutionresolution ~ ~ 350 350 psps
E. FiorettoINFN - LNL
∅∅=1mm =1mm
ηη=1.1mm (FWHM)=1.1mm (FWHM)
•• ItIt isis basedbased on on MicroMicro--ChannelChannel PlatePlate•• activeactive area area 80x100 mm80x100 mm22
•• ddtargettarget = = 25 cm from the target25 cm from the target•• a thin a thin Carbon foilCarbon foil ((20 20 μμg/cmg/cm22) is ) is passedpassed byby
the the particlesparticles at an angle of 135at an angle of 135°°•• EaccEacc ~~ 3030--40 40 kVkV/m/m d(C d(C foilfoil//gridgrid) =) = 1cm1cm•• B B ~~ 120 Gauss120 Gauss
XX
YY
INTAG meetingJanuary 27th, 2005 - Jyväskylä
The Focal Plane Detector: MWPPACThe Focal Plane Detector: MWPPAC
Active area of the FPD:Active area of the FPD:100x13 cm100x13 cm22
MWPPACMWPPAC
CathodeCathode
Anode Anode YY
Al frameAl frame
Al frameAl frameAnode Anode XX
E. FiorettoINFN - LNL
S.Beghini et al.- LNL Ann. Rep. 2000 p.163
Filling gas : CFilling gas : C44HH10 10 Working pressure : 7 Working pressure : 7 hPahPa
INTAG meetingJanuary 27th, 2005 - Jyväskylä
The Focal Plane Detector: ICThe Focal Plane Detector: IC
10 x 4 sections10 x 4 sections10x25 cm10x25 cm22
ICIC
E. FiorettoINFN - LNL
E.Fioretto et al.- LNL Ann. Rep. 2002 p.148
0 10 20 30 40 50 604
6
8
10
12
14
16
18 132Xe
80Se56Fe40Ca35Cl
16O
Ion
Ene
rgy
(MeV
/u)
Atomic Number
CH4
CF4 C4H10
CH4 Si100 hPa 59 μmCHCH4 4 SiSi100 100 hPahPa 59 59 μμmm
CF4 Si100 hPa 168 μmCFCF4 4 SiSi100 100 hPahPa 168 168 μμmm
Maximum working pressure: Maximum working pressure: 100 100 hPahPa
100 cm
INTAG meetingJanuary 27th, 2005 - Jyväskylä
InIn--beam testsbeam tests
ΔΔE/E < 2%E/E < 2%Z/Z/ΔΔZ ~ 60 for Z=20Z ~ 60 for Z=20
ΔΔtt ~ 300 ~ 300 psps, , ΔΔX, X, ΔΔY = 1 mmY = 1 mm
195 MeV 195 MeV 3636S + S + 208208Pb, Pb, θθlablab = 80= 80oo
E (E (a.ua.u.).)
ΔΔE
(E
( a.ua.u .
).)
Z=16Z=16
Z=28Z=28240 MeV 56Fe+124Sn, θlab = 70°
E (E (a.ua.u.).)
ΔΔE
(E
( a.ua.u .
).)
Z=26
X position X position
E. FiorettoINFN - LNL
Y positionY position
INTAG meetingJanuary 27th, 2005 - Jyväskylä
InIn--beam tests : energy resolutionbeam tests : energy resolution
235 235 MeVMeV 4040Ca+Ca+208208PbPb PRISMAPRISMA @ @ θθlablab = 90= 90oo
E. FiorettoINFN - LNL
X (X (a.ua.u.).)
Coun
tsCo
unt s
Inelastic excitations Inelastic excitations of of
octupoleoctupole vibrationsvibrations
The deduced energy resolution is roughly 700 The deduced energy resolution is roughly 700 keVkeV, or 1/300., or 1/300.
Position (energy) spectrumPosition (energy) spectrum
gated on A=40 and Z=20 with the condition of a narrow cone in the entrance MCP detector
2.614 2.614 MeVMeV
INTAG meetingJanuary 27th, 2005 - Jyväskylä
InIn--beam tests : mass resolutionbeam tests : mass resolution
260 260 MeVMeV 5858Ni+Ni+124124Sn, Sn, θθlablab = 70= 70oo
PPAC section #7PPAC section #7
XX
TOF
TOF
A/qA/q
58/1958/19++
59596060
A mass resolution of about 1/220 has been measured A mass resolution of about 1/220 has been measured for neutron pickfor neutron pick--up channelsup channels
E. FiorettoINFN - LNL
gated by a 10 mm × 40 mm window in the (X,Y) matrix of the entrance MCP detector
Z=28 events selected in the IC.Z=28 events selected in the IC.
INTAG meetingJanuary 27th, 2005 - Jyväskylä
First experimental campaign
E. FiorettoINFN - LNL
Shell model in 37P and 39PBreaking of a semi-magic shell
closure far from stability
INTAG meetingJanuary 27th, 2005 - Jyväskylä
82Se+238U
36S+208Pb15
2032S+58Ni
Mirror pair 31S and 31P
54Fe+50CrSpectroscopy of 54Co Isospin non conservingpart of the effective
interaction
64Ni+238UShell model A~60
Shell closure evolution at Shell closure evolution at the magic number N=50the magic number N=50
50
32
Multi-nucleon transfer
Resonances in 24Mg+24Mg and molecular states in 48Cr
27
2840Ca+208Pb
Pairing-vibration states in 42Ca
90Zr+208Pb
24Mg+24Mg
Large-angle scattering
58Ni+60Ni
EE
proton stripping
channels
proton pick-up channels
fission eventsZ=50
Z=34
AprilApril 20042004
ΔΔEE
505 MeV 82Se+238U PRISMA at 64°
Element identification
E. FiorettoINFN - LNL
INTAG meetingJanuary 27th, 2005 - Jyväskylä
Detector thicknessDetector thickness
E. FiorettoINFN - LNL
C foil20 μg/cm2 thick
Mylar foils1.5 μm thick
~ 600 μg/cm2
PRISMA meetingMarch 14th, 2005 - LNL
Mass distributions of reaction productsMass region : A=60-90
Se
As
Br
Kr
Ge
Ga
Zn
Cu
Ni
82
838481
80
77
76
89
8182
7978
808179
78
69
7778
7473
7475
73
7170
6768 72
6564 7170
69
8685
87
81
84 8883
A
505 MeV 82Se+238U PRISMA at 64°
E. Fioretto / INFN - LNL
beam
εεPPACPPAC~100%~100%
7776
75
78 7776
75
74
7980
81
8283
78 7776
75
74
7980
81
8283
GeGe
INTAG meetingJanuary 27th, 2005 - Jyväskylä
INTAG meeting - January 27th, 2005 - Jyväskylä
279
227
121
139
466524352
104011331086
the isomeric 237keV transition is missing in the CLARA-
PRISMA spectrum!
Transitions identified for first time with CLARA-PRISMA
2+→ 0+
8+→ 6+6+→ 4+
4+→ 2+
10+→ 8+
Gammasphere, 64Ni+208PbEur.Phys.J. A 9 (2000) 183
CLARA-PRISMA singles Spectrum
(-6p
-4n)
72Zn
80As(-1p -1n)
Level scheme from a thicktarget GASP exp.
460 MeV 82Se on 192Os
CLARA data
INTAG meetingJanuary 27th, 2005 - Jyväskylä
E. FiorettoINFN - LNL
Mass distributions of reaction products
Zr isotope populationZr isotope population
Events of each line have the same A/q
q=30q=31 q=29
Mass region : A=80-90
560 MeV 90Zr+208Pb PRISMA @ 62°
Z=40 events selected in the ICZ=40 events selected in the IC
E. FiorettoINFN - LNL
εεPPACPPAC~100%~100%
INTAG meetingJanuary 27th, 2005 - Jyväskylä
A mass resolution of about 1/280 has been measured A mass resolution of about 1/280 has been measured
Mass distributions of reaction products
E. FiorettoINFN - LNL
122 MeV 32S+58Ni
92 MeV 24Mg+24Mg
12C
13C
16O
20Ne
21Ne19Ne
24Mg
25Mg
28Si
Mass region : A=12-32
εεPPACPPAC~70%~70%
εεPPACPPAC~90%~90%
INTAG meetingJanuary 27th, 2005 - Jyväskylä
Future Future taggingtagging developmentsdevelopments
E. FiorettoINFN - LNL
Low efficiency for light-ions (60-70%)Low efficiency for lightLow efficiency for light--ions (60ions (60--70%)70%)
INTAG meetingJanuary 27th, 2005 - Jyväskylä
Heavy ions (Heavy ions (E<10 E<10 MeVAMeVA; Z>10; Z>10))
Emissive foil (Emissive foil (VVff = 10 kV= 10 kV))Mylar 0.6 Mylar 0.6 μμm + Al 30 nmm + Al 30 nm
EE
BB
0 V0 V
Accelerating grid (Accelerating grid (VVgg = 0 V= 0 V))
ExtractionExtractionAccelerationAcceleration
GuidingGuidingFocusingFocusing
Detection Detection LPMWPCLPMWPC
Thin window (Thin window (0.9 0.9 μμmm))
PPACPPAC
MWPCMWPCY strips (Wires)Y strips (Wires)
X stripsX strips0 V0 V
HV +HV +
CC44HH1010 –– 5hPa5hPa ΔΔtt ~ 150 ~ 150 pspsΔΔX, X, ΔΔY ~ 2 mmY ~ 2 mm
MylarMylar cathodecathode SeSe--DDSecondarySecondary electronselectrons
TransparencyTransparency ~ ~ 94%94% HigherHigher transparencytransparency
New New MWPPACsMWPPACs
E. FiorettoINFN - LNL
Low efficiency for light-ions (60-70%)Low efficiency for lightLow efficiency for light--ions (60ions (60--70%)70%)
MylarMylar cathodecathode
wires wires ØØ==10 10 μμm m
Future Future taggingtagging developmentsdevelopments
EE
BB
Heavy ions (Heavy ions (E<10 E<10 MeVAMeVA; Z>10; Z>10))
Emissive foil (Emissive foil (VVff = 10 kV= 10 kV))Mylar 0.6 Mylar 0.6 μμm + Al 30 nmm + Al 30 nm
0 V0 V
Accelerating grid (Accelerating grid (VVgg = 0 V= 0 V))ExtractionExtractionAccelerationAcceleration
GuidingGuidingFocusingFocusing
Detection Detection LPMWPCLPMWPC
Thin window (Thin window (0.9 0.9 μμmm))
PPACPPAC
MWPCMWPCY strips (Wires)Y strips (Wires)
X stripsX strips
0 V0 V
HV +HV +
CC44HH1010 –– 5hPa5hPa ΔΔtt ~ 150 ~ 150 pspsΔΔX, X, ΔΔY ~ 2 mmY ~ 2 mm
E. FiorettoINFN - LNL
New FPD for low energy HI New FPD for low energy HI SeSe--DD
Collaboration with UK groups Manchester (Se-D) - Daresbury (ASIC)
Collaboration with UK groups Collaboration with UK groups Manchester (SeManchester (Se--D) D) -- DaresburyDaresbury (ASIC)(ASIC)
~ ~ 400 400 μμg/cmg/cm22
~ ~ 80 80 μμg/cmg/cm22
INTAG meetingJanuary 27th, 2005 - Jyväskylä
SeSe--DD prototypeprototype
Emissive foilEmissive foil
Magnetic field boxMagnetic field box
SeSe--D with mask in VAMOSD with mask in VAMOS
E. FiorettoINFN - LNLPRISMA meeting - February 15th, 2005
ElectronicsElectronics
2x16 analogic channelsSensibility: 3.6 V/pCPeaking time: 1.2 msSerial outputRead-out: Caen RAMS
Gas32 Gas32 boardboard
ASIC ASIC electronicselectronicsApplication Specific Integrated CircuitApplication Specific Integrated Circuit E. Fioretto
INFN - LNLPRISMA meeting
February 15th, 2005
IsomersIsomers
E. FiorettoINFN - LNL
PRISMA meetingMarch 14th, 2005 - LNL
What is an isomer?Metastable (long-lived) excited nuclear state.
Why/When do you get isomers?If there is•large change in spin (“spin-trap”)•dramatic change in structure (shape, K-value)
What do isomers tell you?Isomers occur due to single-particle structure.K-isomers probe both single particle and collective structure.
What is an isomer?Metastable (long-lived) excited nuclear state.
Why/When do you get isomers?If there is•large change in spin (“spin-trap”)•dramatic change in structure (shape, K-value)
What do isomers tell you?Isomers occur due to single-particle structure.K-isomers probe both single particle and collective structure.
ShortShort--lived isomers lived isomers
Promptγ’s
g.s. τ
Isomerτ
E. FiorettoINFN - LNL
τ ≤ 10 ns
PRISMA meetingMarch 14th, 2005 - LNL
LongLong--lived isomerslived isomers
E. FiorettoINFN - LNL
Delayedγ’s
g.s. τ
τ
β
4 CLOVERs detectors
A wall of 40 Si detectors300 μm thick
Active area = 5 x 5 cm2
16 resistive strips
PRISMA meetingMarch 14th, 2005 - LNL
400 ns ≤ τ ≤ 1 μs
OperationOperation in in GasGas--FilledFilled ModeMode
• ER recoiling at or near to 0°• Loss of mass and energy resolution
→ separation of the ERs from the beam particles• PRISMA as separator rather than a spectrometer• Filling gas and working pressures
→ simulations are in progress• Ion species efficiently focused onto a small area at the
the exit of the magnetic dipole (10 x 15 cm2)• The large area of the FPD is not required
→ modification of the FPD• Small dead thickness (no Mylar window)
•• ER recoiling at or near to 0ER recoiling at or near to 0°°•• Loss of mass and energy resolutionLoss of mass and energy resolution
→ separation of the ERs from the beam particlesseparation of the ERs from the beam particles•• PRISMA as separator rather than a spectrometerPRISMA as separator rather than a spectrometer•• Filling gas and working pressuresFilling gas and working pressures
→ simulations are in progresssimulations are in progress•• Ion species efficiently focused onto a small area at the Ion species efficiently focused onto a small area at the
thethe exit of the magnetic dipole (exit of the magnetic dipole (10 x 15 cm10 x 15 cm22))•• The large area of the FPD is not required The large area of the FPD is not required
→ modification of the FPDmodification of the FPD•• Small dead thickness (Small dead thickness (no Mylar windowno Mylar window))
-- Fusion reactions in heavy systemsFusion reactions in heavy systems-- ImplantationImplantation--decay studies (RDT technique)decay studies (RDT technique)-- OffOff--beam spectroscopy beam spectroscopy
E. FiorettoINFN - LNL
INTAG Workshop June 8-9, 2005 - Saclay
Limitations due to the magnetic rigidity
• The average charge state in gas ismuch smaller than in a solid(vacuum), especially at low energy
• Using a central trajectory (Bρ <1.2 Tm) we are limited to A < 180
• With a shift of 30 cm from the central trajectory we can exceedBρ = 1.5 Tm.
• Because of the increase in Bρ at low energy, the rigidity of ERs istypically larger than the beam’s.
• The ratio (BρBEAM)/ (BρER) dependson the energy: careful planning of experiments.
SimulationSimulation resultsresults
E. FiorettoINFN - LNL
INTAG Workshop June 8-9, 2005 - Saclay
EntranceEntrance windowwindow
OperationOperation in in GasGas--FilledFilled ModeMode
DipoleDipole
QuadrupoleQuadrupole
beambeam
FillingFilling gas gas HeHe at P = 1hPaat P = 1hPaANAMARI and TRAJIG ANAMARI and TRAJIG codescodes
1 m
Gas: Gas: 44HeHe
172Y(48Ca, 4n)216ThE = 200 MeV
E. FiorettoINFN - LNL
INTAG Workshop June 8-9, 2005 - Saclay
TaggingTagging detectorsdetectors forfor the GFM the GFM phasephaseJu
nction
Junc
tion
side
side
Ohm
icOhm
icside
side
3 mm3 mm
A A matrixmatrix of 2 x 3 Si of 2 x 3 Si detectorsdetectorsThicknessThickness == 300 300 μμmmActiveActive area = 5 x 5 cmarea = 5 x 5 cm22, 16 , 16 resistiveresistive stripsstrips
SiSi strip detectors for implantation of recoil nucleistrip detectors for implantation of recoil nuclei
PA PA 4 mV/4 mV/MeVMeVAmplAmpl 16 16 chch~ ~ 100 100 electronic
electronicchannels
channels
E. FiorettoINFN - LNL
INTAG Workshop June 8-9, 2005 - Saclay
PRISMA PRISMA collaborationcollaboration
E.Fioretto, A.M. Stefanini, L. Corradi, B.R.Behera, G.de Angelis, A.Gadea, A.Latina, G.Maron, D.R.Napoli, A.Pisent, S.Szilner,
M.Trotta, Y.W. Wu(INFN - LNL)
S.Beghini, G.Montagnoli, F.Scarlassara(Università di Padova and INFN - Padova)
A. De Rosa, G.Inglima, M. La Commara, D.Pierroutsakou, M.Romoli, M.Sandoli
(Università di Napoli and INFN - Napoli)
G.Pollarolo (Università di Torino and INFN - Torino)
D.Ackermann (Univ. of Mainz and GSI, Darmstadt, Germany)
E.FiorettoE.Fioretto, A.M. , A.M. StefaniniStefanini, L. , L. CorradiCorradi, , B.R.BeheraB.R.Behera, G.de Angelis, , G.de Angelis, A.GadeaA.Gadea, A.Latina, , A.Latina, G.MaronG.Maron, , D.R.NapoliD.R.Napoli, , A.PisentA.Pisent, , S.SzilnerS.Szilner, ,
M.TrottaM.Trotta, Y.W. Wu, Y.W. Wu(INFN (INFN -- LNL)LNL)
S.BeghiniS.Beghini, , G.MontagnoliG.Montagnoli, , F.ScarlassaraF.Scarlassara((UniversitUniversitàà didi PadovaPadova and INFN and INFN -- PadovaPadova))
A. De Rosa, A. De Rosa, G.InglimaG.Inglima, M. La , M. La CommaraCommara, , D.PierroutsakouD.Pierroutsakou, , M.RomoliM.Romoli, , M.SandoliM.Sandoli
((UniversitUniversitàà didi NapoliNapoli and INFN and INFN -- NapoliNapoli))
G.PollaroloG.Pollarolo ((UniversitUniversitàà didi TorinoTorino and INFN and INFN -- TorinoTorino))
D.Ackermann D.Ackermann (Univ. of Mainz and GSI, Darmstadt, Germany)(Univ. of Mainz and GSI, Darmstadt, Germany)
E. FiorettoINFN - LNL
INTAG meetingJanuary 27th, 2005 - Jyväskylä
High High spinspin studiesstudies in the in the 7878NiNi and and 132132Sn Sn regionregion
p/Q
ISOL ISOL facilityfacility
Multi-nucleon transfer reactions from grazing to D.I. collisionsMultiMulti--nucleon transfer reactions from grazing to D.I. collisionsnucleon transfer reactions from grazing to D.I. collisions
Coulex, elastic and inelastic excitationsCoulexCoulex, elastic and inelastic excitations, elastic and inelastic excitations
Structure of moderately neutron-rich nuclei populated with binary reactions, in combination with CLARAStructure of moderately neutronStructure of moderately neutron--rich nuclei populated with rich nuclei populated with binary reactions, in combination with CLARAbinary reactions, in combination with CLARA
Near- and sub-barrier fusion of heavy systems, dynamical and shell effectsNearNear-- and suband sub--barrier fusion of heavy systems, dynamical and barrier fusion of heavy systems, dynamical and shell effectsshell effects
Future experiments with radioactive ion beamsFuture Future experimentsexperiments withwith radioactiveradioactive ionion beamsbeams
MainMain physicsphysics guideguide--lineslinesXTU Tandem/PIAVE+ALPI beams PRISMA+CLARAXTU Tandem/PIAVE+ALPI beams PRISMA+CLARA
E. FiorettoINFN - LNL
A
Z
Properties of the nuclear residual Properties of the nuclear residual interactioninteractionEvolutionEvolution of the of the singlesingle--particleparticle levelslevels
40Ca
p p st
ripp
ing
stri
ppin
g
n pickn pick--upup
235 MeV 40Ca + 208Pb
Interaction potential (deformation)Interaction potential (deformation)CollectivityCollectivity
INTAG meetingJanuary 27th, 2005 - Jyväskylä