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