Production of a Positron Microprobe Using a Transmission Remoderator

Fujinami, Masanori; Jinno, Satoshi; Fukuzumi, Masafumi; Kawaguchi, Takumi; Oguma, Koichi; Akahane, Takashi

doi:10.2116/analsci.24.73

Cited by 28 publications

(21 citation statements)

References 21 publications

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“…Three commercially available wire meshes of N = 30, 100 or 150 apertures/inch with d = 0.03 mm were tested in this study, and the distance between two electrodes was fixed to 10 mm; thus, d/w and w/L values were listed in Table I. Generally, the brightness β of a positron beam is defined as [6,8,9]:…”

Section: Methods and Resultsmentioning

confidence: 99%

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Design of an Acceleration Gap for Brightness Enhancement in a Reactor-Based Slow Positron Beamline

et al. 2017

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Design of an acceleration gap using mesh electrodes of the brightness enhancement system for the slow positron beamline of Kyoto University research reactor was studied to improve the performance of brightness enhancement. The transmittance and the increase in the angular divergence of the beam resulting from acceleration with the mesh electrode were estimated by trajectory simulations. The effect of the increase in the beam emittance on the beam radius at the focus point was estimated based on the analytical solution of the beam envelope equation. Using the obtained beam transmittance and beam radius, the beam brightness after remoderation was evaluated. Then, the influence of the mesh electrode configuration on the brightness was investigated.

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Section: Methods and Resultsmentioning

confidence: 99%

“…We use a 150-nm-thick Ni (100) thin film [5] as a remoderator purchased from the University of Aarhus. The principle of the brightness enhancement method is described in detail elsewhere [3,[6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Design of an Acceleration Gap for Brightness Enhancement in a Reactor-Based Slow Positron Beamline

et al. 2017

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“…It has been demonstrated by many authors that this parameter is extremely sensitive to the presence of openvolume defects, such as vacancies, their clusters and dislocation lines, and jogs at dislocation lines, where positrons can be trapped and annihilate. More technical details about the PPMA constructed at the Chiba University in Japan were given in the papers by Fujinami et al [16] and Oshima et al [20].…”

Section: The Ppma Measurementsmentioning

confidence: 99%

The Positron Probe Microanalyser Studies of Defect Distribution Induced by Machining of Copper, Iron and Titanium

et al. 2015

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We demonstrate the application of the new experimental technique: positron probe microanalyser for studies of the defect profiles induced by milling. Metal foils of Cu, Fe and Ti were subjected to machining in a milling machine with different cutting speed. This technique revealed well-defined profiles of defects below the machined surface which was extended up to hundreds of micrometres. The extent of the profile depended on the metal and the cutting speed. The positron probe microanalyser allowed us to trace the evolution of the profile after annealing in different temperatures. Surprisingly, the high thermal stability of a few tens of micrometres thick layer adjacent to the machined surface was detected.

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“…Scanning positron microscopes (SPM) have been developed to apply PAS to very small samples or samples with small features of interest [3][4][5][6][7]. Slow positron beams of SPMs focus on samples where the beam spot size is less than a few tens of µm.…”

Section: Introductionmentioning

confidence: 99%

“…The advantage of such a SPM is that it can obtain two or three dimensional PAS images using the scanning lateral injection position (xy) and the implantation depth (z) of the focused beams, which allow the defect distributions to be visually evaluated. The AIST microbeam system [8] uses an electron linear accelerator (LINAC) to produce positrons [9,10], and consequently, its beam intensity (10 6 e + /s) is 10-100 times higher than those of the other SPMs [3][4][5][6], which use radioisotopes as the positron source. Therefore, the AIST microbeam system can obtain PAS images within a reasonable time (~10 3 pixels/hour) [11] and hence, SPM may be a practical tool.…”

Section: Introductionmentioning

confidence: 99%

Development of Positron Microbeam in AIST

Oshima

Suzuki

Ohdaira

et al. 2008

MSF

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Abstract. To improve the spatial resolution of positron annihilation spectroscopy (PAS), a system to produce an intense positron microbeam was developed in AIST. A slow positron beam, which was produced by an electron linear accelerator, was focused by a lens onto a remoderator to enhance its brightness. The brightness-enhanced beam with an intensity of ≈1 × 10 6 e + /s was extracted from the remoderator and focused onto the sample by a lens. The beam size at the sample was 25 µm, which is more than two and half orders of magnitude smaller than that in the magnetic transport system (≈10 mm). Hence, the spatial resolution of PAS with an AIST positron microbeam can be drastically improved relative to PAS using conventional methods.

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Production of a Positron Microprobe Using a Transmission Remoderator

Cited by 28 publications

References 21 publications

Design of an Acceleration Gap for Brightness Enhancement in a Reactor-Based Slow Positron Beamline

Design of an Acceleration Gap for Brightness Enhancement in a Reactor-Based Slow Positron Beamline

The Positron Probe Microanalyser Studies of Defect Distribution Induced by Machining of Copper, Iron and Titanium

Development of Positron Microbeam in AIST

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