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Title: The Intense Slow Positron Beam Facility at the NC State University PULSTAR Reactor

Journal Article · · AIP Conference Proceedings
DOI:https://doi.org/10.1063/1.3120175· OSTI ID:21289669
; ; ;  [1]; ;  [2];  [3]
  1. Nuclear Engineering/Nuclear Reactor Program, North Carolina State University, P.O. Box 7909, Raleigh NC 27695 (United States)
  2. Physics Department, University of Michigan, 450 Church Street, Ann Arbor MI 48109 (United States)
  3. Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 (United States)

An intense slow positron beam is in its early stages of operation at the 1-MW open-pool PULSTAR research reactor at North Carolina State University. The positron beam line is installed in a beam port that has a 30-cmx30-cm cross sectional view of the core. The positrons are created in a tungsten converter/moderator by pair-production using gamma rays produced in the reactor core and by neutron capture reactions in cadmium cladding surrounding the tungsten. Upon moderation, slow ({approx}3 eV) positrons that are emitted from the moderator are electrostatically extracted, focused and magnetically guided until they exit the reactor biological shield with 1-keV energy, approximately 3-cm beam diameter and an intensity exceeding 6x10{sup 8} positrons per second. A magnetic beam switch and transport system has been installed and tested that directs the beam into one of two spectrometers. The spectrometers are designed to implement state-of-the-art PALS and DBS techniques to perform positron and positronium annihilation studies of nanophases in matter.

OSTI ID:
21289669
Journal Information:
AIP Conference Proceedings, Vol. 1099, Issue 1; Conference: CAARI 2008: 12. international conference on application of accelerators in research and industry, Fort Worth, TX (United States), 10-15 Aug 2008; Other Information: DOI: 10.1063/1.3120175; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
Country of Publication:
United States
Language:
English