Design and beam dynamics of a Transmission Electron Microscope electron gun assembly

Munawar Iqbal; Faizan Elahi; Abul Rehman; Abdul Wasy Zia; Ghalib ul Islam; Zhou Zusheng

doi:10.1016/j.vacuum.2019.04.039

Design and beam dynamics of a Transmission Electron Microscope electron gun assembly

Munawar Iqbal^*
, Faizan Elahi
, Abul Rehman
, Abdul Wasy Zia
, Ghalib ul Islam
, Zhou Zusheng

^*Corresponding author for this work

Department of Mechanical Engineering

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

5 Citations (Scopus)

Abstract

We present the design and beam dynamics analysis of a Transmission Electron Microscope illumination system. A LaB₆ emitter is used as a cathode/source with an emissive surface area of diameter 50 μm generating fixed emission current of 5 mA which is biased by −300 V with Wehnelt electrode. The gun is comprised of five electrostatic lenses in-between the focusing and anode electrodes to accelerate and focus the beam with integrated energy of 160 keV in the post anode region with diameter around 228 μm. Finally, the beam is focused using the condensed electro-magnetic lenses of field strengths 183 mT and 331 mT, respectively to spot size 1.8 μm in the post-lens position. The obtained focal spots are largely symmetric along the two transverse directions. The illumination system geometry offers full beam collimation control. The study provides a theoretical basis for the structure and optics design of the Transmission Electron Microscope.

Original language	English
Pages (from-to)	283-289
Journal	Vacuum
Volume	165
Online published	20 Apr 2019
DOIs	https://doi.org/10.1016/j.vacuum.2019.04.039
Publication status	Published - Jul 2019

Bibliographical note

Full text of this publication does not contain sufficient affiliation information. With consent from the author(s) concerned, the Research Unit(s) information for this record is based on the existing academic department affiliation of the author(s).

Research Keywords

Electron gun
Accelerating electrode
Magnetic lens
Illumination system
TEM

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title = "Design and beam dynamics of a Transmission Electron Microscope electron gun assembly",

abstract = "We present the design and beam dynamics analysis of a Transmission Electron Microscope illumination system. A LaB6 emitter is used as a cathode/source with an emissive surface area of diameter 50 μm generating fixed emission current of 5 mA which is biased by −300 V with Wehnelt electrode. The gun is comprised of five electrostatic lenses in-between the focusing and anode electrodes to accelerate and focus the beam with integrated energy of 160 keV in the post anode region with diameter around 228 μm. Finally, the beam is focused using the condensed electro-magnetic lenses of field strengths 183 mT and 331 mT, respectively to spot size 1.8 μm in the post-lens position. The obtained focal spots are largely symmetric along the two transverse directions. The illumination system geometry offers full beam collimation control. The study provides a theoretical basis for the structure and optics design of the Transmission Electron Microscope.",

keywords = "Electron gun, Accelerating electrode, Magnetic lens, Illumination system, TEM",

author = "Munawar Iqbal and Faizan Elahi and Abul Rehman and \{Wasy Zia\}, Abdul and Islam, \{Ghalib ul\} and Zhou Zusheng",

note = "Full text of this publication does not contain sufficient affiliation information. With consent from the author(s) concerned, the Research Unit(s) information for this record is based on the existing academic department affiliation of the author(s).",

year = "2019",

month = jul,

doi = "10.1016/j.vacuum.2019.04.039",

language = "English",

volume = "165",

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T1 - Design and beam dynamics of a Transmission Electron Microscope electron gun assembly

AU - Iqbal, Munawar

AU - Elahi, Faizan

AU - Rehman, Abul

AU - Wasy Zia, Abdul

AU - Islam, Ghalib ul

AU - Zusheng, Zhou

N1 - Full text of this publication does not contain sufficient affiliation information. With consent from the author(s) concerned, the Research Unit(s) information for this record is based on the existing academic department affiliation of the author(s).

PY - 2019/7

Y1 - 2019/7

N2 - We present the design and beam dynamics analysis of a Transmission Electron Microscope illumination system. A LaB6 emitter is used as a cathode/source with an emissive surface area of diameter 50 μm generating fixed emission current of 5 mA which is biased by −300 V with Wehnelt electrode. The gun is comprised of five electrostatic lenses in-between the focusing and anode electrodes to accelerate and focus the beam with integrated energy of 160 keV in the post anode region with diameter around 228 μm. Finally, the beam is focused using the condensed electro-magnetic lenses of field strengths 183 mT and 331 mT, respectively to spot size 1.8 μm in the post-lens position. The obtained focal spots are largely symmetric along the two transverse directions. The illumination system geometry offers full beam collimation control. The study provides a theoretical basis for the structure and optics design of the Transmission Electron Microscope.

AB - We present the design and beam dynamics analysis of a Transmission Electron Microscope illumination system. A LaB6 emitter is used as a cathode/source with an emissive surface area of diameter 50 μm generating fixed emission current of 5 mA which is biased by −300 V with Wehnelt electrode. The gun is comprised of five electrostatic lenses in-between the focusing and anode electrodes to accelerate and focus the beam with integrated energy of 160 keV in the post anode region with diameter around 228 μm. Finally, the beam is focused using the condensed electro-magnetic lenses of field strengths 183 mT and 331 mT, respectively to spot size 1.8 μm in the post-lens position. The obtained focal spots are largely symmetric along the two transverse directions. The illumination system geometry offers full beam collimation control. The study provides a theoretical basis for the structure and optics design of the Transmission Electron Microscope.

KW - Electron gun

KW - Accelerating electrode

KW - Magnetic lens

KW - Illumination system

KW - TEM

UR - https://www.scopus.com/pages/publications/85064614243

UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-85064614243&origin=recordpage

U2 - 10.1016/j.vacuum.2019.04.039

DO - 10.1016/j.vacuum.2019.04.039

M3 - RGC 21 - Publication in refereed journal

SN - 0042-207X

VL - 165

SP - 283

EP - 289

JO - Vacuum

JF - Vacuum

ER -

Design and beam dynamics of a Transmission Electron Microscope electron gun assembly

Abstract

Bibliographical note

Research Keywords

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