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Coupling ORRUBA and GRETINA

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  1. Coupling ORRUBA and GRETINA Steven D. Pain Oak Ridge National Laboratory • ORRUBA • Coupling with GS • Coupling with GRETINA • Instrumentation GRETINA Workshop, ANL, February 2013

  2. Coupling ORRUBA and GRETINA Steven D. Pain Oak Ridge National Laboratory • ORRUBA • Coupling with GS • Coupling with GRETINA • Instrumentation GRETINA Workshop, ANL, February 2013

  3. Oak Ridge Rutgers University Barrel Array • Barrel array of ion-implanted silicon strip detectors • Custom resistive design used to achieve good position resolution (~1mm) without requiring 1000s of electronics channels • 2 rings – q < 90°: 12 telescopes (1000mm R + 65mm NR) • – q > 90°: 12 detectors (500mm R) • ORRUBA gives ~80% f coverage over q = 45° → 135° • 288 electronics channels

  4. ORRUBA Detector Design 5.0 4.0 3.0 Energy Loss (MeV) 2.0 d 1.0 p 0.0 10.0 5.0 15.0 Residual Energy (MeV)

  5. GODDESS GammasphereORRUBA: DualDetectorsforExperimentalStructureStudies

  6. GODDESS Polar angle coverage 15 to 165 degree coverage (>75%) 1 deg (polar) resolution over most angles New end-cap detectors under design

  7. GODDESS Channel Count One ring 1-layer (132 ch) One ring telescopes (220 ch) Endcap 1 layer (128 ch) Endcap 3-stack (136 - 384 ch) Forward hemisphere = 356 - 604 ch Backward hemisphere = 260 ch Total preamplifers = 720 ch (complete coverage requires 616 ch)

  8. GRETINA performance for light-ion transfer reactions 138Xe(d,p) 138Xe(d,t) ~0.5 deg (0.05 deg) ~ 1 deg (~0.1 deg) ~3% ~3% 0.01% 0.01% 2 keV 2 keV 2 deg 2 deg Recoil direction Recoil energy (target thickness) Recoil energy (reaction) Intrinsic resolution of Ge detector Measured angle of gamma ray Gammasphere ~13 keV GRETINA ~3 keV

  9. ORRUBA + GRETINA Physical Coupling Fits inside standard (DGS) GRETINA chamber Marginally tighter squeeze inside GS Room to bring out electronics?

  10. ORRUBA + GRETINA Physical Coupling

  11. Instrumentation Backward hemisphere = 260 ch Forward hemisphere = 356 - 604 ch Complete coverage = 616 ch and up Conventional instrumentation FMA Focal Plane DSSD electronics 320 channels ORNL electronics ~300 channels Digital instrumentation FMA Focal Plane DSSD electronics 320 digitizers + GRETINA aux channels? + DGS?

  12. November 2011 – ANL tests • Pre-amplifiers mounted on top of “chimney” • Required some 6 feet of signal cable before any amplification • Ineffective shielding between feed-through and preamplifiers • Led to resolution degradation over usual performance (~ 30% effect) > 5 feet

  13. November 2011 – ANL tests Signals run the length of the FMA (2 x 25 ft cables) Instrumented with RAL shaping amplifiers, and CAMAC ADCs of Darek Sewerniak Data also taken with Darek’s GRETINA digitizers (14 bit, 100 MHz) 228Th source for calibration of the ORRUBA detectors, and 249Cf was used to perform an a-g coincidence measurement Digital Analog

  14. Instrumenting Resistive Strips Energy and position filters? 0.5ms 1.0ms 1.5ms

  15. ORRUBA fits within GRETINA chamber Coupling with Gammasphere underway Hardware built New end-cap detectors Most of GODDESS setup could be equally used with GRETINA In standalone mode, or if there was sufficient distance to the FMA quad Radial alternatives possible (would require more hardware fabrication, and longer un-amplified signal cables) Combination of ORRUBA and GRETINA could give excellent (few keV) energy resolution Both conventional ADC or digitized readout of ORRUBA are options Sufficient conventional channels exist Performance benefits to using digitizers Summary

  16. Acknowledgements Andrew Ratkiewicz – not entirely convinced by the dinosaurs at the creation museum Postdoc MPhys student Thanks also to the UTK machine shop, Darek Sewerniak, Mike Carpenter, Shaofei Zhu and Kim Lister…. Callum Shand keeping out of the Texas heat Steven Hardy – proud of his detector mounts

  17. Instrumenting Resistive Strips A = Shaping time too short B = Shaping time better matched Energy A B Position Position

  18. Instrumenting Resistive Strips Energy and position filters? 0.5ms 1.0ms 1.5ms