Scanning positron microbeam

Abstract

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 1.8×105 e+ s−1 cm−2 rad−2 V−1 Ci−1. The beam of 8000 e+ s−1 is brought to a 10×50 μm2 focus by a sectored lens and is scanned across a test grid. Possible applications to defect spectroscopy and the observation of small samples will be discussed.

High-intensity positron microprobe at the Thomas Jefferson National Accelerator Facility

“…19,20 Thus several stages of positron a) Author to whom correspondence should be addressed. Electronic mail: serkan.golge@nasa.gov (re)moderation, a process known as brightness enhancement, 21 are required to obtain the desired spatial resolution at the expense of losing a significant fraction of the intensity of the positrons.…”

High Current Pulsed Positron Microprobe

“…Many of the beam characteristics described above have been obtained in separate systems [1][2][3] and a design for an efficient, low source strength microprobe has been reported [4].…”

Analytical Methods Using a Positron Microprobe

“…Brandes et al achieved ~5 μm spatial resolution with an electrostatic lens and two stages of brightness enhancements. 26 Kögel et al focused the primary beam with a magnetic single pole lens placed behind a remoderator chamber, and ultimately achieved a φ2 μm beam with conventional SEM optics. 24,27 A reflectiontype remoderator, or W(100) single-crystal block, has been adopted in these systems, because a high-temperature anneal is easy to remove the defects and the impurities involved.…”