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### Fragment Mass Analyzer

Darek Seweryniak, ANL

C. N. Davids et al., Nucl. Instrum. Meth., B 70, 358 (1992).

GAMMASPHERE+FMA

- Resonances in rp-process nuclei
- n-rich nuclei A~60
- N~Z nuclei
- 101Sn
- Proton emitters
- a emitters
- Transfermium nuclei
- …

GRETINA at ATLAS workshop, March 2013

GRETINA+FMA

- Can we extend the GS-FMA reach?
- Larger FMA solid angle
- Higher Ge rates?
- Better Doppler correction
- (recoil angle and energy)
- Polarization
- No dead time
- Campaign in January 2013
- Important step towards GRETA

GRETINA at ATLAS workshop, March 2013

Argonne Fragment Mass Analyzer

Mass resolution: dM/M~1/350

Angular acceptance: DW=8 msr(2 msr)

Energy acceptance: DE/E=+/-20%

M/Q acceptance: D(M/Q)/(M/Q)=10%

Flight path 8.2m

Max(Br)=1.1Tm

Max(Er)=20MV

Can be rotated off 0 degrees

Can be moved along the axis

Different focusing modes

Q1

Q2

ED1

MD

M1

40 cm

ED2

M2

Q3

Q4

M3

DSSD

FP

GRETINA at ATLAS workshop, March 2013

FMA at 293 mm and 900 mm

Qy,max=0.0401 rad

Qy,max=0.0295 rad

Qx,max=0.0495 rad

Qx,max=0.0167 rad

W=7.4 msr

W~1.8 msr

GRETINA at ATLAS workshop, March 2013

FMA angular acceptance

58Ni+50Cr at 220 MeV

Fraction of accepted recoil

2 msr 8 msr gain

alpha+p+2n 0.13 0.47 X3.6

p+2n 0.44 0.93 X2.1

Based on PACE calculations.

GRETINA at ATLAS workshop, March 2013

Existing focal plane detectors

- Parallel Grid Avalanche counter
- Very good spatial resolution
- Modest rate capability <10 kHz
- Fairly thin windows (2X120 micron mylar foils)

- Parallel Foil Avalanche counter
- Very good spatial resolution
- High rate capability (tested to 30 kHz)
- More material (two additional foils)

- Channel plate detector
- Worse spatial resolution
- High rate capability (100 kHz)
- Very thin

- Ionization chamber
- Isobutane
- 200 micron window
- 3 segments - 5cm+5cm+20cm
- Pressure <25 Torr

GRETINA at ATLAS workshop, March 2013

Micro-channel plate detector

- 4X12 cm2 whole focal plane
- high rates 100 kHz
- good spatial resolution (magnets)
- much lower energy loss
- better Z resolution
- less angular straggling

B. diGiovine

Photonis Inc., USA

GRETINA at ATLAS workshop, March 2013

160X160 DSSD

Large area Si

Si/PiN box

plastic b dets

Implantation stationRecoil-Decay Tagging (protons,alphas,betas,conversion electros, gamma rays, …)

GRETINA at ATLAS workshop, March 2013

Implantation station

- Suite of DSSDs
- 48X48, 16X16mm2
- 40X40, 40X40mm2
- 80X80, 32X32mm2
- 160X160, 64X64mm2,
- 100 mm - protons
- 140 mm - alphas
- 300 mm - beta delayed protons
- 1000 mm - betas

- Large area Si veto detector: 5X5cm
- Escape detectors
- 4 SSSD in a box geometry, 7 strips, 4X6cm2
- PiN diode detector array, 4 2X2 detectors

GRETINA at ATLAS workshop, March 2013

- 5 clover detectors in a box geometry
- 64x64 mm, 160x160 DSSD
- Mobile frame

GRETINA at ATLAS workshop, March 2013

11

FMA Digital DAQbased on GRETINA, developed in parallel with DGS

- Trigerless
- DSSD (320 chans)
- X-array (20 chans)
- focal plane (20 chans)
- Resolution comparable to analog (Ge/Si)
- Pulse shape analysis
- 100 kHz/DSSD possible

100MHz, 14-bit Digitizer

M. Cromaz et al., A 597 (2008) 233–237

DDAQ was used in 4 experiments (two with DGS)

Trigger and Time control module

J.T. Anderson et al., 2007, IEEE Nuclear Science

Symposium Conference Record, p. 1751

GRETINA at ATLAS workshop, March 2013

Possible GRETINA-FMA configurations

60 cm

New frame

30 cm

like BGS

30 cm

New

idea

30-60-90 cm

GRETINA at ATLAS workshop, March 2013

Thank you for your attention!

GRETINA at ATLAS workshop, March 2013

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