Fragment Mass Analyzer Darek Seweryniak ANL C N

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 § 101 Sn § Proton emitters § a emitters § Transfermium nuclei § … GRETINA at ATLAS workshop, March 2013 2

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 3

Argonne Fragment Mass Analyzer Mass resolution: d. M/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. 2 m Max(Br)=1. 1 Tm Max(Er)=20 MV Can be rotated off 0 degrees Can be moved along the axis Different focusing modes M 1 40 cm Q 1 Q 2 ED 1 MD ED 2 M 2 Q 3 Q 4 M 3 FP DSSD GRETINA at ATLAS workshop, March 2013 4

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 5

FMA angular acceptance 58 Ni+50 Cr at 220 Me. V Fraction of accepted recoil 2 msr 8 msr gain alpha+p+2 n 0. 13 0. 47 X 3. 6 p+2 n 0. 44 0. 93 X 2. 1 Based on PACE calculations. GRETINA at ATLAS workshop, March 2013 6

Existing focal plane detectors § Parallel Grid Avalanche counter – Very good spatial resolution – Modest rate capability <10 k. Hz – Fairly thin windows (2 X 120 micron mylar foils) § Parallel Foil Avalanche counter – Very good spatial resolution – High rate capability (tested to 30 k. Hz) – More material (two additional foils) § Channel plate detector – Worse spatial resolution – High rate capability (100 k. Hz) – Very thin § Ionization chamber – – Isobutane 200 micron window 3 segments - 5 cm+20 cm Pressure <25 Torr GRETINA at ATLAS workshop, March 2013 7

Micro-channel plate detector § § 4 X 12 cm 2 whole focal plane high rates 100 k. Hz good spatial resolution (magnets) much lower energy loss – better Z resolution – less angular straggling B. di. Giovine Photonis Inc. , USA GRETINA at ATLAS workshop, March 2013 8

Implantation station Ge clovers 160 X 160 DSSD Large area Si Si/Pi. N box plastic b dets Recoil-Decay Tagging (protons, alphas, betas, conversion electros, gamma rays, …) GRETINA at ATLAS workshop, March 2013 9

Implantation station § Suite of DSSDs – – 48 X 48, 16 X 16 mm 2 40 X 40, 40 X 40 mm 2 80 X 80, 32 X 32 mm 2 160 X 160, 64 X 64 mm 2, • • 100 mm - protons 140 mm - alphas 300 mm - beta delayed protons 1000 mm - betas § Large area Si veto detector: 5 X 5 cm § Escape detectors – 4 SSSD in a box geometry, 7 strips, 4 X 6 cm 2 – Pi. N diode detector array, 4 2 X 2 detectors GRETINA at ATLAS workshop, March 2013 10

X-array § § § 5 clover detectors in a box geometry 64 x 64 mm, 160 x 160 DSSD Mobile frame GRETINA at ATLAS workshop, March 2013 11

FMA Digital DAQ based 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 k. Hz/DSSD possible 100 MHz, 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 GRETINA at ATLAS workshop, March 2013 J. T. Anderson et al. , 2007, IEEE Nuclear Science Symposium Conference Record, p. 1751 12

Possible GRETINA-FMA configurations 60 cm New frame 30 cm like BGS New idea 30 cm 30 -60 -90 cm GRETINA at ATLAS workshop, March 2013 13

Thank you for your attention! GRETINA at ATLAS workshop, March 2013 14