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TACTIC: A New Detector for Nuclear Astrophysics. An update for the ACTAR meeting, Daresbury, UK 12-13 th June 2006. Paul Mumby-Croft Nuclear Physics Group, University of York, UK. T RIUMF A nnular C hamber for the T racking and I dentification of C harged Particles.
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TACTIC: A New Detector for Nuclear Astrophysics An update for the ACTAR meeting, Daresbury, UK 12-13th June 2006. Paul Mumby-Croft Nuclear Physics Group, University of York, UK
TRIUMF Annular Chamber for the Tracking and Identification of Charged Particles Original concept: L. Buchmann, TRIUMF
How is it going to work? • 90% helium 10% CO2 gas mixture • Pressure of a few hundred mbar • Drift voltage ~100V/cm
Technical drawings (Daresbury, P.Amaudruz)
Technical drawings (Daresbury, P.Amaudruz)
Technical drawings + GEANT4 (G. Ruprecht, TRIUMF)
Technical drawings + GEANT4 (G. Ruprecht, TRIUMF)
The cathode cage • Purpose: to reduce background ionisation electrons
The End. Thanks to the TACTIC collaboration: A. Laird1, G. Ruprecht2, D. Gigliotti2, P. Amaudruz2, L. Buchmann2, S. Fox1, B. Fulton1, T. Kirchner2,R. Openshaw2, M. Pavan2, J. Pearson2, G. Sheffer2, P. Walden2. Thanks to R. Veenhof3 for help with GARFIELD Thanks to Rob, Kal, and Roy at Daresbury 1) Department of Physics, University of York, York, YO10 5DD, UK. 2) TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada 3) CERN, CH-1211 Genève 23, Switzerland
Technical drawings (Daresbury, P.Amaudruz)
Motivation • To investigate astrophysical charged-particle reactions • Low energies and low flux RIBs • Need good solid angle coverage (c.f. the LEDA array) • Initial design caters for 8Li(a, n)11B reaction • Recent r-process models are sensitive to this reaction rate (Sasaqui et al. ApJ 634 2005) • Transitions to excited states make important contribution • Factor of ~2 difference in published reaction rates (Boyd et al. 1992; Gu et al. 1995; Mizoi et al. 2000; Paradellis et al. 1990).
The Gas Electron Multiplier (Pictures from CERN) • Thin Kapton foil (50um) with 10um copper on each side • Etched with 50um diameter holes
E-potential around the cathode cage • Electrons want to drift ‘uphill’
Summary • New detector for charged particle reactions • Active target configuration using GEMs • Measures timing and total energy, allowing vertex reconstruction • Technical drawings very near completion, construction begins at York this summer.
What has been done so far? (G. Ruprecht, TRIUMF)
Drift time: is it uniform in phi? Drift velocity and drift time are fairly insensitive to E (V/cm) at these energies.
Overview of presentation • What is a TACTIC? • Why do we need it? • How is it going to work?