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Development of an In-Situ Positron Beamline for Materials Science.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Development of an In-Situ Positron Beamline for Materials Science./
Author:	Chung, Thai hang.
Description:	1 online resource (94 pages)
Notes:	Source: Masters Abstracts International, Volume: 85-03.
Contained By:	Masters Abstracts International85-03.
Subject:	Quantum physics. -
Online resource:	click for full text (PQDT)
ISBN:	9798380375849

Development of an In-Situ Positron Beamline for Materials Science.
Chung, Thai hang.

Development of an In-Situ Positron Beamline for Materials Science. - 1 online resource (94 pages)

Source: Masters Abstracts International, Volume: 85-03.

Thesis (M.S.)--Bowling Green State University, 2023.

Includes bibliographical references

One of the key aspects in developing advanced nuclear reactor technology is the stability of the materials, which directly impacts the reactor's lifespan. These materials are subject to coupled extreme environmental stresses such as high radiation, corrosive media, and large temperature gradients, which synergistically contribute to the buildup of defects and eventual material failure. To build a comprehensive understanding of defect evolution, it is important to study the early stages of defect evolution, beginning with the formation of vacancies, voids, dislocations, and non-equilibrium defects. On the experimental front, it is challenging to quantify these vacancy-type defects with standard characterization techniques, as it requires sub-nanometer resolution. Positron Annihilation Spectroscopy (PAS) bridges this gap, comprising a set of non-destructive techniques capable of directly detecting atomic-scale defects, at concentrations as low as 1 vacancy per ten million atoms.This thesis will detail the work done for the ongoing development of two positron beamlines, with an emphasis on the beamline used for in-situ investigations of ion-induced damage in nuclear materials. The first measurements using the newly developed beamline are presented for low-dose radiation-induced self-ion damage in Fe. Later, refinements to the apparatus and experimental design are also discussed with regards to revisiting the experiment. Additionally, two studies on a class of high-performance multi-principal element/high-entropy alloys are discussed. Using positron annihilation lifetime Spectroscopy (PALS) and Doppler broadening spectroscopy (DBS), the phase structure and chemical complexity effects on MoNbTi-based alloys are explored with evidence of radiation resistance in MoNbTiZr and MoNbTi as well as defect recovery observed in MoNbTiVZr. Finally, exploratory measurements using DBS on a ternary mutli-principal element alloys (MPEA), CoCrNi, have recently been performed on the BGSU positron beamline. Using PAS to characterize defects, we attempt to find evidence of chemical short-range order structures in CoCrNi.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798380375849Subjects--Topical Terms:

1179090
Quantum physics.
Subjects--Index Terms:

Positron Annihilation SpectroscopyIndex Terms--Genre/Form:

554714
Electronic books.

Development of an In-Situ Positron Beamline for Materials Science.
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