Gaseous scintillation detection and amplification in variable pressure scanning electron microscopy

Morgan, SW; Phillips, MR

Gaseous scintillation detection and amplification in variable pressure scanning electron microscopy

Morgan, SW Phillips, MR

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Publication Type:: Journal Article
Citation:: Journal of Applied Physics, 2006, 100 (7)
Issue Date:: 2006-10-20

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Field	Value	Language
dc.contributor.author	Morgan, SW	en_US
dc.contributor.author	Phillips, MR https://orcid.org/0000-0003-1522-9281	en_US
dc.date.issued	2006-10-20	en_US
dc.identifier.citation	Journal of Applied Physics, 2006, 100 (7)	en_US
dc.identifier.issn	0021-8979	en_US
dc.identifier.uri	http://hdl.handle.net/10453/762
dc.description.abstract	This work investigates the generation and detection of gaseous scintillation signals produced in variable pressure scanning electron microscopy through electron-gas molecule excitation reactions. Here a gaseous scintillation detection (GSD) system is developed to efficiently detect photons produced via excitation reactions in electron cascades. Images acquired using GSD are compared to those obtained using conventional gaseous secondary electron detection (GSED) and demonstrate that images rich in secondary electron (SE) contrast can be achieved using the gaseous scintillation signal. A theoretical model, based on existing Townsend theories, is developed. It describes the production and amplification of photon signals generated by cascading SEs, high energy backscattered electrons, and primary beam electrons. Photon amplification (the total number of photons produced per sample emissive electron) is then investigated and compared to conventional electronic amplification over a wide range of microscope operating parameters, scintillating imaging gases, and photon collection geometries. These studies revealed that argon gas exhibited the largest GSD gain, followed by nitrogen then water vapor, exactly opposite to the trend observed for electron amplification data. It was also found that detected scintillation signals exhibit larger SE signal-to-background levels compared to those of conventional electronic signals detected via GSED. Finally, dragging the electron cascade towards the light pipe assemblage of GSD systems, or electrostatic focusing, dramatically increases the collection efficiency of photons. © 2006 American Institute of Physics.	en_US
dc.relation	http://purl.org/au-research/grants/arc/LE0560850
dc.relation.ispartof	Journal of Applied Physics	en_US
dc.relation.isbasedon	10.1063/1.2355539	en_US
dc.subject.classification	Applied Physics	en_US
dc.title	Gaseous scintillation detection and amplification in variable pressure scanning electron microscopy	en_US
dc.type	Journal Article
utslib.citation.volume	7	en_US
utslib.citation.volume	100	en_US
utslib.for	0204 Condensed Matter Physics	en_US
utslib.for	01 Mathematical Sciences	en_US
utslib.for	02 Physical Sciences	en_US
utslib.for	09 Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - CCET - Centre for Clean Energy Technology
utslib.copyright.status	closed_access
pubs.issue	7	en_US
pubs.publication-status	Published	en_US
pubs.volume	100	en_US

Abstract:

This work investigates the generation and detection of gaseous scintillation signals produced in variable pressure scanning electron microscopy through electron-gas molecule excitation reactions. Here a gaseous scintillation detection (GSD) system is developed to efficiently detect photons produced via excitation reactions in electron cascades. Images acquired using GSD are compared to those obtained using conventional gaseous secondary electron detection (GSED) and demonstrate that images rich in secondary electron (SE) contrast can be achieved using the gaseous scintillation signal. A theoretical model, based on existing Townsend theories, is developed. It describes the production and amplification of photon signals generated by cascading SEs, high energy backscattered electrons, and primary beam electrons. Photon amplification (the total number of photons produced per sample emissive electron) is then investigated and compared to conventional electronic amplification over a wide range of microscope operating parameters, scintillating imaging gases, and photon collection geometries. These studies revealed that argon gas exhibited the largest GSD gain, followed by nitrogen then water vapor, exactly opposite to the trend observed for electron amplification data. It was also found that detected scintillation signals exhibit larger SE signal-to-background levels compared to those of conventional electronic signals detected via GSED. Finally, dragging the electron cascade towards the light pipe assemblage of GSD systems, or electrostatic focusing, dramatically increases the collection efficiency of photons. © 2006 American Institute of Physics.

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http://hdl.handle.net/10453/762