first results of the magnex large-acceptance spectrometer
DESCRIPTION
First results of the MAGNEX large-acceptance spectrometer. F.Cappuzzello. LEA COLLIGA October 13-15, LNS (Catania). A.Cunsolo, F.Cappuzzello, M.Cavallaro, A.Foti, S.E.A.Orrigo , M.R.D.Rodrigues INFN-LNS, Catania, Italy INFN, Sez. Catania, Catania, Italy - PowerPoint PPT PresentationTRANSCRIPT
First results of the MAGNEX large-acceptance
spectrometer F.Cappuzzello
LEA COLLIGAOctober 13-15, LNS (Catania)
The MAGNEX collaboration
A.Cunsolo, F.Cappuzzello, M.Cavallaro, A.Foti,
S.E.A.Orrigo, M.R.D.Rodrigues
INFN-LNS, Catania, Italy
INFN, Sez. Catania, Catania, ItalyUniversità di Catania, Catania, Italy
A.Bonaccorso, T.Borello, P.Guazzoni,
H.Lenske, H.Petrascu, C.L.Rodrigues, J.S.Winfield, L.Zetta
INFN, Sez. Pisa, Pisa, and Sez. Milano, Milano, ItalyUniversity of S. Paulo, IFUSP, Brazil
Universitatat Giessen, Giessen, GermanyNIPNE, Bucarest, RomaniaGSI, Darmstadt, Germany
The MAGNEX spectrometer
Planned experiments
First results from the initial experiments
Topics
Maximum magnetic rigidity 1.8 T• m
Solid angle 51 msr
E max /E min 1.7
Total energy resolution (target 1 mm2) (90% of full acceptance)
1000
Mass resolution 250
A.Cunsolo et al., NIMA 481 (2002) 48
A.Cunsolo et al., NIMA 484 (2002) 56
E <30 AMeV
2 < A < 40
E < 25 AMeV
40 < A < 93
Upper bent limits
Possible definition: spectrometer based on the solution of the equation of motion of each single detected particle
Practically one needs
Detailed knowledge of the magnetic field maps
Algorithms for high order solution of equation of motion and inversion
of transport matrices
Detectors to measure positions and angles at the focus
Ray-trace spectrometer
•V.A.Shchepunov et al., NIMB 204 (2003) 447
•A.Lazzaro et al.,I.P.C.S.175 (2005) 171
•A.Lazzaro et al., NIMA 570 (2007) 192
•A.Cunsolo et al., E.P.J. 150 (2007) 343
•A.Lazzaro et al., NIMA 585 (2008) 136
•A.Lazzaro et al., NIMA 591 (2008) 394
•P.Guazzoni et al., IEEE accepted
Initial commissioning means a series of tests with different beams and Initial commissioning means a series of tests with different beams and targets with a targets with a small scattering chambersmall scattering chamber
Limit of the Limit of the fixed anglefixed angle at 25 at 2555
Limit of the Limit of the beam energybeam energy (10 MV High Voltage on Tandem terminals) (10 MV High Voltage on Tandem terminals)
Initial commissioning
Alpha source at the target-object pointMAGNEX in large acceptance mode
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
X_foc (m) X_foc (m)
_f
oc (
rad)
Cou
nts
Charge State distribution (diamonds)
Agreement with results from INTENSITY calculations (triangles)
J.A.Winger et al., Nucl. Instr. Meth. B 70 (1992) 380
13 14 15 16 17 18 19 20 21
Log
fra
ctio
n
100
10-1
10-2
10-3
48Ti + 197Au elastic scattering at 120 MeV
Momentum dispersion
2 measurements of Xfoc with same magnet settings but with 48Ti beam energy changed by 2.6%
Result: 3.68 cm/% for K = -0.1
Measure of i via trajectory reconstruction 16O + 58Ni 16O + 58Ni at 80 MeV
i (rad)
Cou
nts
Diaphragm(1-mm holes)58Ni target
16O beam MAGNEX black box
FWHM 10 mr
Consistent with the holes size
elastic scattering
DWBA calculations
Spectroscopy of ligth neutron rich nuclei via the CEX reaction (7Li,7Be) at Tandem energies
Experiments with quasi stable 14C (18 O) Tandem beams
Spectroscopic studies of heavy ions via (p,t) direct 2n pick-up and via (66Li,d) -transfer (next month)
8He spectroscopy via the 7Li(8Li,7Be)8He ( EXCYT beam) at 52 MeV
Experiments of nuclear astrophysics (Trojan Horse Method)
Experiments with the LNS K800 Superconducting Cyclotron beams (e.g. pionic fusion at subthreshold energies)
Experimental lines
Targets : AlF3, 27Al and 12C,
Final Nuclei : 19O and 27Mg,
Beam energy 52 MeV,
Data under reduction.
Ligth neutron rich nuclei Spectroscopy via the (Ligth neutron rich nuclei Spectroscopy via the (77Li,Li,77Be) CEX reactionBe) CEX reaction
First measurements (December 2007)
Lab = 7 19.5
= 50 msr
Energy byte = 27%
Cou
nts
E/E 1000
gs96 keV
19O
PRELIMINARY (~10% statistics)
19F(7Li,7Be)19O at Einc = 52,4 MeV
19.8 keV/ch
Target: 13C 100 g/cm2
Selected reaction channels (18O,17O) (18O,16O) (18O,15O)
Reasidual nuclei 14C, 15C and 16C
Beam energy 84 MeV,
Data under reduction.
Multi-neutron transfer by 18 O Tandem beams
First Experiment (January 2008)
Lab = 7 19.5
= 50 msr
Energy byte = 27%
13C(18O,16O)15C at Einc = 84 MeV
Er Residual energy (MeV)
Xf (
m)
16O 8+
15O 8+
17O 8+18O 8+18O 7+18O 6+
PRELIMINARY Xf (m)
Yf (
m)
0.74g.s.
4.22
PRELIMINARY
Particle identification without TOF
Not reconstructed focal plane position spectrum
Conclusions
MAGNEX has successfully started its experimental program (first experiment December 2007).
Other two experiments already performed 13C(18O, 16,15O)15,16C on January 2008 and 28Si(7Li,7Be)28Al on July 2008.
A new experiment is scheduled next month.
The results coming out from data analysis are very encouraging
Inversion of transport matrices
Large acceptance condition
For MAGNEX up to 11th order !
Differential algebra (Ex:COSY INFINITY) M. Berz et al., PRC 47 (1993) 537
))(( 1
*1
1 nnnn MAIAM Iterative formula for the
inverse matrix
),,,,(
),,,,(
),,,,(
),,,,(
),,,,(
'5
'4
'3
'2
'1
fffff
fffffi
fffffi
fffffi
fffffi
lyxF
lyxF
lyxFy
lyxF
lyxFx
.....)()()()(,
kj
kjijkj
jiji ixixTixRfx
f instead of i for MAGNEX
The PSD start detector
-channel
Pads
Gassiplex motherboards
A.Cunsolo et al., NIMA 495 (2002) 216
Trapezoidal geometry
Window length 92 cm. Height
20 cm. Depth 16 cm
Isobutane pressure between 5 e
50 mbar
Energy threshold down to 0.5
MeV/amu
No intermediate foils
Maximum counting rate 4 kHz
Ion
The FPD detector
Reconstructing trajectories
ANGULAR AND MASS RESOLUTIONANGULAR AND MASS RESOLUTION Angular and mass resolution are ~ ion-independent Angular and mass resolution are ~ ion-independent
0,09
0,10
0,11
0,12
0,13
0,14
0,15
0 1 2 3 4 5 6 7 8 9 10 11 12
Reconstruction order
Stat
. Err
. on
scat
teri
ng a
ngle
(deg
)
40
60
80
100
120
140
160
180
200
0 1 2 3 4 5 6 7 8 9 10 11 12
Reconstruction order
Mas
s re
solv
ing
pow
er
◆ 1.8 Tm ~ 38 MeVu
▲ 0.5 Tm ~ 3 MeV/u
■ 1.06 Tm ~13 MeVu
6Li + 12C (100 g/cm2)6Li + 12C (100 g/cm2)
Reconstructing trajectoriesEnergy resolving power for 6Li + 12C (100 g/cm2)Energy resolving power for 6Li + 12C (100 g/cm2)
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9 10 11 12
Reconstruction order
Ene
rgy
reso
lvin
g po
wer
0
100200
300
400500
600
700
800900
1000
0 1 2 3 4 5 6 7 8 9 10 11 12
Reconstruction orderEn
ergy
res
olvi
ng p
ower
◆ 1.8 Tm ~ 38 MeVu a)
■ 1.06 Tm ~13 MeVu a)
▲ 0.5 Tm ~ 3 MeV/u b)
● 0.815 Tm 8 MeV/u b)
a) LNS – Cyclotron energiesb) LNS - Tandem energies
a) LNS – Cyclotron energiesb) LNS - Tandem energies
A.Lazzaro et al. 7th ICAP, East Lansing, 2002, IOP series 175, pagg. 171-180
LNS Tandem
E [MeV]
E [MeV]
Eres [MeV]
Eres [MeV]
9Be
Z = 3Z = 2
7Be
7Be1
2
7Li + AlF3
l = 25° 5°
El = 40.2 MeV
TOF [sec]
TOF [sec]
xfoc [m]
xfoc [m]
7Be
9Be
7Be
1
2
7Li + AlF3, l = 25° 5°, El = 40.2 MeV