180 likes | 285 Views
Coupling ORRUBA and GRETINA. Steven D. Pain Oak Ridge National Laboratory. ORRUBA Coupling with GS Coupling with GRETINA Instrumentation. GRETINA Workshop, ANL, February 2013. Coupling ORRUBA and GRETINA. Steven D. Pain Oak Ridge National Laboratory. ORRUBA Coupling with GS
E N D
Coupling ORRUBA and GRETINA Steven D. Pain Oak Ridge National Laboratory • ORRUBA • Coupling with GS • Coupling with GRETINA • Instrumentation GRETINA Workshop, ANL, February 2013
Coupling ORRUBA and GRETINA Steven D. Pain Oak Ridge National Laboratory • ORRUBA • Coupling with GS • Coupling with GRETINA • Instrumentation GRETINA Workshop, ANL, February 2013
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
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)
GODDESS GammasphereORRUBA: DualDetectorsforExperimentalStructureStudies
GODDESS Polar angle coverage 15 to 165 degree coverage (>75%) 1 deg (polar) resolution over most angles New end-cap detectors under design
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)
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
ORRUBA + GRETINA Physical Coupling Fits inside standard (DGS) GRETINA chamber Marginally tighter squeeze inside GS Room to bring out electronics?
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?
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
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
Instrumenting Resistive Strips Energy and position filters? 0.5ms 1.0ms 1.5ms
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
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
Instrumenting Resistive Strips A = Shaping time too short B = Shaping time better matched Energy A B Position Position
Instrumenting Resistive Strips Energy and position filters? 0.5ms 1.0ms 1.5ms