ANASEN - Array for Nuclear Astrophysics Studies with Exotic Nuclei Silicon-strip detector array backed with 2-cm-thick CsI Gas proportional counter for proton-tracking capability Supported by NSF MRI Program Here: 1) Nuclear Structure studies of light nuclei 2) Nuclear Astrophysics measurements To improve understanding of light rare isotopes and (p,  ) and ( ,p) rates that are important in the  p/rp processes Flexible, large-area charged-particle detector array targeting ( ,p) reactions, proton scattering, and transfer reactions using the ReA3 facility at the NSCL and RESOLUT at FSU Active Target Jeff Blackmon (LSU), Grigory Rogachev (FSU), Ingo Wiedenhoever (FSU) and Ed Zganjar (LSU)

ANASEN 3 Rings of 12 Super-X3 silicon-strip detectors backed w/ 2cm thick CsI Annular silicon-strip array RIB Anode wires of cylindrical gas proportional counter

Silicon Strip Detectors X3 detectors constructed for ORRUBA by Micron Semiconductor 4 resistive strips (10mm X 75mm) S.D. Pain et al., NIMB261 (2007) EpEp Forward angle detectors currently under design 18cm outer diameter in 4 quadrants (6” Si) Minimal (~1mm) PC board on outer radius Pin out and mounting along radial direction 8cm ID design for use with PC  x < 1 mm  E < 100 keV “Super-X3” version 40x19 mm Ohmic segmentation First 12 detectors ordered 1 mm thick detectors Micron QQQ2 design

Proton-Resonant Scattering with ANASEN  Thick, active target allows simultaneous measurement of multiple resonances  Proton-depth tracking allows distinction between elastic and inelastic excitations Same depth, different Ep ? Beam slows down in target gas, scans over Resonance energies p Beam View

Structure of 8 B P. Navratil et al., PRC 73, (2006) D. Morris & A. Volya Study of light exotic nuclei through resonance reactions with RNB’s RNB8, 2009

Structure of 8 B G.V. Rogachev et al., Phys. Rev. C64 (2001) (R) Be+p Dominant configuration for the “missing” states is 7 Be * (1/2 - )+p. Should be observed in inelastic scattering. D. Halderson, PRC 69, (2004) Study of light exotic nuclei through resonance reactions with RNB’s RNB8, 2009

RF-Resonator Magnetic Spectrograph Target Position RF-Resonator Magnetic Spectrograph Solenoid 2 Solenoid 1 Mass selection slits Production target  In-flight production of radioactive beams in inverse kinematics  Combination of Superconducting RF-Resonator with high acceptance magnetic Spectrograph to create mass spectrometer RESOLUT: a new radioactive beam facility at John D. Fox Superconducting Accelerator Lab. at Florida State University

Hybrid (thick/thin) target technique  Target is thick enough for 7 Be to lose significant fraction of it’s energy.  But thin enough for 7 Be recoils to make it out of the target. 7 Be p CH 2 E1 E3 RESOLUT beam composition: 75% of 7 Be, 25% of 7 Li Study of light exotic nuclei through resonance reactions with RNB’s RNB8, Li(p,n) 7 Be I 7Be =2x10 5 pps

Study of light exotic nuclei through resonance reactions with RNB’s RNB8, 2009 Excitation function of inelastic p+ 7 Be scattering compared to R- matrix calculations with no new states in 8 B. Elastic Inelastic 140 o U. Greife, et al., NIM B 261 (2007) 1089

Study of light exotic nuclei through resonance reactions with RNB’s RNB8, Be(p,p) 148 o 7 Be(p,p) 140 o 7 Be(p,p) 132 o 7 Be(p,p’) 7 Be* 146 o 7 Be(p,p’) 7 Be * 138 o 7 Be(p,p’) 7 Be * 130 o Red curve is an R-matrix fit with the following resonances: MeV; known [1] MeV; new MeV; known [1] MeV; new MeV; known [2,3] ~3.5 MeV; new

( ,p) with ANASEN as active target Top View +HV p p Beam View  Chamber filled with ~ Torr He gas  Beam enters through ~ 2  m Ti foil  Protons produced with energies from few  ~20 MeV in extreme cases  4 He( 18 Ne,p): E p ~3-11 MeV  For 10 MeV protons,  E ~ 5 keV in PC region  10 5 e  Resistive wire  good determination of position in PC Example: 36 MeV 18 Ne  22 MeV 18 Ne after window (4 MeV cm )  E lab ~0.68 MeV/cm in 200 Torr  E cm ~120 keV/cm

( ,p) - count rates, resolution, issues  Entire excitation function measured with 1 bombarding energy  Should be able to measure (a,p) cross section over a significant fraction of the Gamow window - though more difficult for heavier Z  E cm can be reconstructed with good (<100 keV cm ) resolution, but oMore difficult for forward/backward angles oDependent on emittance of beam oThickness required of PC for accurate position reconstuction? oLeakage of charge from high ionization region of beam into PC

Proton scattering and (p,  ) with ANASEN  Our understanding of (p,  ) and ( ,p) reactions can be improved by studying nuclear structure via proton elastic scattering proton inelastic scattering (p,  ) reactions  p-process Red = Most interesting cases

Neutron-Detector Development: 6 Li-Glass Sandwich (d,n) in inverse kinematics: Detect low-energy, keV neutrons in “backward” directions γ-p branching ratios and angular distributions Plan: use 6 Li-glass scintillator-stack (5 cm depth=10% efficient.) 25 Al p n 15 cm 26 Si CD 2