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Title: Positron microprobe at LLNL

Abstract

The electron linac based positron source at Lawrence Livermore National Laboratory (LLNL) provides the world's highest current beam of keV positrons. We are building a positron microprobe that will produce a pulsed, focused positron beam for 3-dimensional scans of defect size and concentration with sub-micron resolution. The widely spaced and intense positron packets from the tungsten moderator at the end of the 100 MeV LLNL linac are captured and trapped in a magnetic bottle. The positrons are then released in 1 ns bunches at a 20 MHz repetition rate. With a three-stage re-moderation we will compress the cm-sized original beam to a 1 micro-meter diameter final spot on the target. The buncher will compress the arrival time of positrons on the target to less than 100 ps. A detector array with up to 60 BaF2 crystals in paired coincidence will measure the annihilation radiation with high efficiency and low background. The energy of the positrons can be varied from less than 1 keV up to 50 keV.

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Defense Programs (DP)
OSTI Identifier:
3112
Report Number(s):
UCRL-JC-132420
KC0201010; ON: DE00003112
DOE Contract Number:  
W-7405-Eng-48
Resource Type:
Conference
Resource Relation:
Conference: SLOPOS-8 Conference/8th International Workshop on Slow Positron Beam Techniques for Solid and Surfaces, Cape Town, South Africa, September 6-12, 1998
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; Positrons; Beams; Probes

Citation Formats

Asoka, P, Howell, R, and Stoeffl, W. Positron microprobe at LLNL. United States: N. p., 1998. Web.
Asoka, P, Howell, R, & Stoeffl, W. Positron microprobe at LLNL. United States.
Asoka, P, Howell, R, and Stoeffl, W. 1998. "Positron microprobe at LLNL". United States. https://www.osti.gov/servlets/purl/3112.
@article{osti_3112,
title = {Positron microprobe at LLNL},
author = {Asoka, P and Howell, R and Stoeffl, W},
abstractNote = {The electron linac based positron source at Lawrence Livermore National Laboratory (LLNL) provides the world's highest current beam of keV positrons. We are building a positron microprobe that will produce a pulsed, focused positron beam for 3-dimensional scans of defect size and concentration with sub-micron resolution. The widely spaced and intense positron packets from the tungsten moderator at the end of the 100 MeV LLNL linac are captured and trapped in a magnetic bottle. The positrons are then released in 1 ns bunches at a 20 MHz repetition rate. With a three-stage re-moderation we will compress the cm-sized original beam to a 1 micro-meter diameter final spot on the target. The buncher will compress the arrival time of positrons on the target to less than 100 ps. A detector array with up to 60 BaF2 crystals in paired coincidence will measure the annihilation radiation with high efficiency and low background. The energy of the positrons can be varied from less than 1 keV up to 50 keV.},
doi = {},
url = {https://www.osti.gov/biblio/3112}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Nov 01 00:00:00 EST 1998},
month = {Sun Nov 01 00:00:00 EST 1998}
}

Conference:
Other availability
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