TITLE

Development and use of a thin-film transmission positron moderator

AUTHOR(S)
Lynn, K. G.; Nielsen, B.; Quateman, J. H.
PUB. DATE
August 1985
SOURCE
Applied Physics Letters;8/1/1985, Vol. 47 Issue 3, p239
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A narrow energy beam of slow positrons can be generated by moderating the beta-decay spectrum of a radioactive β[sup +] source. We report here the development and use of the first moderator in which the low-energy positrons are not extracted from the surface facing the β[sup +] emitter but from the opposite surface, i.e., the transmission moderator. An advantage is that such a configuration eliminates the problem of moderated positrons passing by the radioactive source. This is an essential problem when the source is physically large such as the present commerically available Na[sup 22] sources. This moderator is a 5000-Å self-supporting W (100) film. The growth and treatment of the film were found to provide a high-quality positron moderator. The slow to fast positron conversion efficiency, using a Na[sup 22] source, was found to be 4 × 10[sup -4].
ACCESSION #
9817945

 

Related Articles

  • Study of DX center in Cd0.8Zn0.2Te:Cl by positron annihilation. Fung, S.; Shan, Y.Y.; Deng, A.H.; Ling, C.C.; Beling, C.D.; Lynn, K.G. // Journal of Applied Physics;8/15/1998, Vol. 84 Issue 4, p1889 

    Presents information pertaining to the study of the DX center in cadmium (Cd)0.8 zinc (Zn)0.2 tellurium (Te):chlorine (Cl) at 50 K, using positron beam and positron annihilation experiments. Details on how the Cd0.8Zn0.2Te crystal was grown; Method used to conduct positron diffusion and trapping...

  • The creation of high quality positron beams using traps. Greaves, R. G. // AIP Conference Proceedings;2002, Vol. 606 Issue 1, p3 

    High quality positron beams are currently used for a variety of applications in science and technology. One of the most demanding applications is as analytical tools for surface and materials science, where ultra-short positron pulses (<200 ps) and microscopic beams (< 1 micron in diameter) are...

  • A High Intensity Positron Source at Saclay: The SOPHI Project. Rey, J.-M.; Blideanu, V.; Carty, M.; Coulloux, G.; Curtoni, A.; Delferrière, O.; Forest, F.; Lancelot, J. L.; Liszkay, L.; Neuvéglise, D.; Pérez, P.; Ruiz, N.; Sauce, Y. // AIP Conference Proceedings;3/15/2009, Vol. 1099 Issue 1, p944 

    We are building the SOPHI experiment in Saclay, which is a device based on a small 5 MeV electron linac [1] to produce positrons via pair production on a tungsten target. This device should provide 108 slow e+/s, i.e. a factor 300 greater than the strongest activity Na22 based setup. The SOPHI...

  • Variable-energy positron-beam studies of SiO2/Si irradiated by ionizing radiation. Uedono, A.; Tanigawa, S.; Suzuki, K.; Watanabe, K. // Applied Physics Letters;8/8/1988, Vol. 53 Issue 6, p473 

    Variable-energy positron-beam studies have been carried out on Si with a 1.61 μm overlayer of SiO2 irradiated by x ray and γ ray up to the dose of 5×105 R. The Doppler broadening of annihilation photons was found to be strongly influenced by x-ray irradiation, and the effect was...

  • Vacancy defects in thin-film La[sub 0.5]Sr[sub 0.5]CoO[sub 3-δ] observed by positron annihilation. Keeble, D. J.; Krishnan, A.; Friessnegg, T.; Nielsen, B.; Madhukar, S.; Aggarwal, S.; Ramesh, R.; Poindexter, E. H. // Applied Physics Letters;7/27/1998, Vol. 73 Issue 4 

    Vacancy-related defects in laser ablated thin films of the conducting metal–oxide La[sub 0.5]Sr[sub 0.5]CoO[sub 3-δ] were detected using a variable-energy positron beam. The nonstoichiometry, δ, was altered by varying the oxygen partial pressure within the deposition chamber present...

  • Creation of a monoenergetic pulsed positron beam. Gilbert, S.J.; Kurz, C. // Applied Physics Letters;4/14/1997, Vol. 70 Issue 15, p1944 

    Investigates the creation of a monoenergetic pulsed positron beam. Variety of frequency, duration, and amplitude of pulses; Approaches used for the generation of slow positron beams; Use of a Penning trap to develop positron storage and handling techniques.

  • Scanning positron microbeam. Brandes, G. R.; Canter, K. F.; Horsky, T. N.; Lippel, P. H.; Mills, A. P. // Review of Scientific Instruments;Feb1988, Vol. 59 Issue 2, p228 

    The construction and operation of a scanning positron microbeam is reported. The positrons are obtained from a doubly remoderated positron beam with a normalized brightness-per-volt of 1.8 × 10[sup 5] e[sup +] s[sup -] cm[sup -2] rad[sup -2] V[sup -1] Ci[sup -2]. The beam of 8000 e[sup +]...

  • Role of implantation-induced defects in surface-oriented diffusion of fluorine in silicon. Szeles, Cs.; Nielsen, B.; Asoka-Kumar, P.; Lynn, K. G.; Anderle, M.; Ma, T. P.; Rubloff, G. W. // Journal of Applied Physics;9/15/1994, Vol. 76 Issue 6, p3403 

    Deals with a study which investigated open-volume defects introduced in silicon (100) crystals during fluorine implantation by variable-energy positron beam depth profiling. Experimental details; Results and discussion.

  • Vacancy generation resulting from electrical deactivation of arsenic. Lawther, D.W.; Myler, U. // Applied Physics Letters;12/11/1995, Vol. 67 Issue 24, p3575 

    Examines the electrical deactivation of arsenic in highly doped silicon using the positron beam technique. Evidence linking the formation of arsenic-vacancy complexes to the deactivation process; Basis for determining the average number of arsenic atoms per complex; Significance of...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics