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Measuring positron scattering cross sections in a magnetic field

Abstract

Full text: Until recently, low energy positron scattering has been limited in scope by the typically poor resolution of moderated positron sources (dE {approx} 0.5 eV or greater). The advent of the buffer gas trapping technique has made available a positron source with an energy spread of 25 meV or better, tunable from 0.1 to 100 eV, promising to open up new areas of study low energy positron scattering. The high-resolution positron beam is formed in a magnetic field of 1.5 kG, which rules out a conventional electrostatic scattering experiment. New scattering techniques have been developed which take advantage of the properties of the magnetised positron beam, and allow a variety of scattering cross sections to be measured. This paper will present an overview of the buffer gas scattering technique, and describe the analysis techniques developed for measuring scattering cross sections in a magnetic field. Techniques for measuring differential elastic, integral inelastic, grand total and total positronium cross sections will be explained. Examples of these measurements will also be given, and compared with existing theoretical calculations and electron scattering data. Future prospects for this type of measurement will be explored, including extension to electron scattering. A new positron trap will  More>>
Authors:
Sulliman, J; [1]  Gilbert, S J; Marler, J P; [2]  Graves, R G; [3]  Buckman, S J [4] 
  1. Photon Factory, KEK, Tsukuba (Japan)
  2. UCSD, La Jolla, CA (United States). Physics Department
  3. First Point Scientific, Agoura Hills, CA (United States)
  4. The Australian National University, Canberra, ACT (Australia). Research School of Physical Sciences and Engineering
Publication Date:
Jul 01, 2002
Product Type:
Conference
Resource Relation:
Conference: 15. Biennial Congress of the Australian Institute of Physics. Physics and industry working together, Sydney, NSW (Australia), 8-11 Jul 2002; Other Information: PBD: 2002; Related Information: In: 15th Biennial Congress of the Australian Institute of Physics incorporating Australian Conference of Optical Fibre Technology (ACOFT) and Australian Optical Society (AOS). Handbook and abstracts, 235 pages.
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DIFFERENTIAL CROSS SECTIONS; EDUCATIONAL FACILITIES; ELASTIC SCATTERING; ELECTRON DIFFRACTION; EV RANGE 01-10; EV RANGE 10-100; INELASTIC SCATTERING; MAGNETIC FIELDS; MAGNETIZATION; NEUTRON DIFFRACTION; POSITRON BEAMS; POSITRON SOURCES; POSITRONIUM; POSITRONS; RESOLUTION; SUPERCONDUCTING MAGNETS; TOTAL CROSS SECTIONS; TRAPPING
OSTI ID:
20619915
Research Organizations:
Australian Institute of Physics (Australia)
Country of Origin:
Australia
Language:
English
Other Identifying Numbers:
TRN: AU0524593063565
Availability:
Available in abstract form only, full text entered in this record
Submitting Site:
INIS
Size:
page(s) 199
Announcement Date:
Aug 28, 2005

Citation Formats

Sulliman, J, Gilbert, S J, Marler, J P, Graves, R G, and Buckman, S J. Measuring positron scattering cross sections in a magnetic field. Australia: N. p., 2002. Web.
Sulliman, J, Gilbert, S J, Marler, J P, Graves, R G, & Buckman, S J. Measuring positron scattering cross sections in a magnetic field. Australia.
Sulliman, J, Gilbert, S J, Marler, J P, Graves, R G, and Buckman, S J. 2002. "Measuring positron scattering cross sections in a magnetic field." Australia.
@misc{etde_20619915,
title = {Measuring positron scattering cross sections in a magnetic field}
author = {Sulliman, J, Gilbert, S J, Marler, J P, Graves, R G, and Buckman, S J}
abstractNote = {Full text: Until recently, low energy positron scattering has been limited in scope by the typically poor resolution of moderated positron sources (dE {approx} 0.5 eV or greater). The advent of the buffer gas trapping technique has made available a positron source with an energy spread of 25 meV or better, tunable from 0.1 to 100 eV, promising to open up new areas of study low energy positron scattering. The high-resolution positron beam is formed in a magnetic field of 1.5 kG, which rules out a conventional electrostatic scattering experiment. New scattering techniques have been developed which take advantage of the properties of the magnetised positron beam, and allow a variety of scattering cross sections to be measured. This paper will present an overview of the buffer gas scattering technique, and describe the analysis techniques developed for measuring scattering cross sections in a magnetic field. Techniques for measuring differential elastic, integral inelastic, grand total and total positronium cross sections will be explained. Examples of these measurements will also be given, and compared with existing theoretical calculations and electron scattering data. Future prospects for this type of measurement will be explored, including extension to electron scattering. A new positron trap will be described, which will use a 5T superconducting magnet and cryogenically cooled walls to trap and cool greater numbers of positrons at lower temperatures than previously possible. This will give access to even lower energy and higher resolution measurements than are currently possible. This research was performed at University of California, San Diego and supported by NSF and ONR. Steve Buckman would also like to acknowledge support from the Fulbright association.}
place = {Australia}
year = {2002}
month = {Jul}
}