[PPT] - South Eastern Applied Materials Research Centre Principles and PowerPoint Presentation

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South Eastern Applied Materials Research Centre Principles and Applications of X-ray Micro Tomography

Presented by

Dr. Ramesh Raghavendra

SEAM Centre Director & Technology Gateway Manager Presented to: MSI 2015 Symposium University of Limerick, 27th August 2015

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Presentation Outline

SEAM Introduction & activities
X-ray tomography origin
X-ray tomography- Principles and Method
X-ray micro-tomography applications – Case Studies

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SEAM is a Materials Science and

Engineering Research Centre working both in industrial and academic spheres, with the aim of bridging the gap between academia and industry.

SEAM

is based within Waterford Institute of Technology, Waterford.

SEAM Launched in 2009
Member of EI Technology Gateway

Network, a nationwide resource for industry delivering solutions on near to market problems for industrial partners

SEAM – Who We Are…..

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What does SEAM do?

SEAM, regarded as one of Ireland’s leading Technology Gateways offer Engineering Materials Technology supports to industries Provide unique world class professional services to industries and undertake materials research based projects

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SEAM Core Capabilities

CT

scan (X-ray tomography): Non destructive 3D analysis of materials and components

Product

design

ptimisation

through

verlaying of scanned CT data over original

CAD data

3D Metrology solutions
Finite

Element Modelling (FEM)

f

components & systems

Failure analysis of product components
Provider of bespoke solutions for customer

specific issues

3D Metal Additive Manufacturing

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Two walk–in CT Systems at SEAM (Probably the only place in the world to have 2-walk in systems in an academic institute)

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Nanotom (180 kV) at SEAM

Samples up to 60mm Φ
Plastics and small metal samples

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V|TOME|X L 300 (dual tube) at SEAM

Samples up to 600mm Φ
Large heavy metal samples (up to 90mm solid Ni based

super-alloys

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SEAM’S OTHER KEY CAPABILITIES

Finite Element Analysis

Ansys work bench (Commercial License) Two high performance work stations

Synthesis and characterisation of:
Polymeric materials
Adhesives
Glass and glass-ceramics
Failure Analysis of :
Medical devices and bio-material components
Structural and electronic components
Act as one stop shop for getting job done through external

sources for any materials related investigations which are beyond SEAM resource capabilities

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SEAM’s Impeccable Industry Collaborative Record

Established collaborations with over 100 Irish Based Industries
75% of SEAM clients are Multinationals (MNCs) and 25% are

Indigenous clients

Executed over 800 direct funded Industrial projects since 2009

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SEAM Client Companies

SEAM currently assists over 100 companies in Ireland

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Recognition

Won Knowledge Transfer Ireland (KTI) Award 2015 under Industrial Consultancy Impact category

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Developing an arthoscopically accessible cartilage

defect measuring device (EI Commercialisation program).

Collaborating with PMBRC to produce a prolonged

release Injectable Delivery system for a certain medical condition (Com fund programme)

Development of a novel sensor system for real

time in-situ monitoring of Tool wear in Precision Engineering Applications (EU: FP7-SME Program; Project Co-ordinator Dr. Ramesh Raghavendra)

Supervising Two Ph.Ds & 2 WIT Mech Engg

student projects

Providing placement training for WIT Engg

graduates

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SEAM’s current Applied Research/Academic Activities

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X-ray Micro Computed Tomography (XMT)

Theory and Applications

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Tomography

: ‘Tomos’ = slice or section + ‘graphy’ = field of study

Alessandro Vallebona. Invented the principle of tomography in 1930

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Sir Godfrey Hounsfield developed first medical CT scanner in 1969 His work was funded by EMI mainly due to the the success of The Beatles in the 1960’s.

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What is X-Ray Microtomography (XMT)?

X-ray microtomography is a non-destructive

analysis technique used to visualise and characterise objects in three dimensions.

It is the process of imaging an object from

many directions using penetrating radiation (e.g. X-rays) and using a computer to determine the interior structure of that object from these projected images

XMT can be considered as a miniaturised

version of medical CT or CAT scanning

X-ray projection image 3D Reconstructed model

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X-Ray Gun Detector Manipulator

X-Ray Computed Tomography -Components of a µCT system

180 kV Tungsten Target 2 MP CMOS Detector

~1080 projections acquired

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The Method

The method involves the acquisition of a series of x-ray projection images

(similar to those used by a medical doctor to diagnose a broken bone) at a known number of angular positions through 360 degrees.

Variation in the contrast of each projection image relates to how the x-rays

are attenuated as they penetrate the sample.

X-ray attenuation increases proportionally to both the electron density and

thickness of the sample material thus resulting in a darker project image.

X-ray must penetrate sample at all angles through 360°
Specialised mathematical calculations known as 'reconstruction algorithms'

are used to create a 3D image from the x-ray projections.

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X-ray attenuation increases proportionally to both the electron

density and thickness of the sample material thus resulting in a darker project image.

X-ray must penetrate sample at all angles through 360°
Specialised mathematical calculations known as 'reconstruction

algorithms' are used to create a 3D image from the x-ray projections.

X-Ray Microtomography basics –contd..

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X-ray Microtomography: Data Reconstruction

Axial slice views are computed from the x-ray projections using

back projection reconstruction algorithms

3D rendering of the all axial slice views allows visualisation of the 3D

model

X-ray projections Computed axial slice 3D rendered model

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Visualisation software permits numerous analysis options from creating sections through the 3D model to quantification of size, internal porosity, surface area or segmentation based on differences in density.

X-ray Microtomography: Data Analysis

0.3 mm 0.2 mm

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XMT components: X-ray Tube (source)

Positively charged anode
Negatively charged cathode

– Heated filament releases electrons (e-) – e- are accelerated towards positively charged anode – Kinetic energy related to the voltage potential – e- strike anode target generating

Heat (up to 99%)
X-rays

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XMT components: X-ray Tube (source) contd..

Sources available in various powers and focal spot abilities. Seam utilise high performance variable focus tubes

Nanofocus (0.8µm) 180kV
Microfocus (3µm) 300kV

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XMT components: Detector panel

Scintillator Material

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XMT components: Detector Panel

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XMT components- Scintillator

Typically one of two materials:

CsI – Cesium Iodide
Gadox – Gadolinium oxysulfide

CsI is more sensitive but prone to higher levels of ghosting. Gadox is less susceptible to ghosting but less sensitive. CsI is used in VTOMEX L 300 Gadox is used in Nanotom system

Fabrication and imaging characterization of high sensitive CsI(Tl) and Gd2O2S(Tb) scintillator screens for X-ray imaging detectors: Bo Kyung Cha, Jong Yul Kim, Cheulmuu Sim, Gyuseong Cho

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X-ray Computed Tomography

Achieving Magnification

Sample diameters from sub-mm to 500mm. Detail detectability to below 1µm Height ranges up to 600mm. Weight capacity up to 50kg. Rule of thumb for calculating spatial resolution (µm): Largest dimension (mm) divided by 2000.

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Case Studies

Dental frameworks
Tablet discolouration
Powder Application Demonstration

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Dental Frameworks

The problem:

Many different systems exist to create cast CoCr denture

frameworks using impressions taken from a patient’s mouth

Which, if any, sprueing system produces the most

geometrical accurate casting?

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

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Overview of the Components

Framework 1 Framework 2 Framework 3

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

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Overview of the Components – contd… Model Framework

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

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Overview of the Components- contd..

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

Framework 1 Framework 2 Framework 3

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Frameworks Aligned to Model

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

Framework 1 Framework 2 Framework 3

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Nominal Comparison

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

Framework 1 Framework 2 Framework 3

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Deviation Comparison

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

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Conclusion

Sample 1 is the best overall match to the model.

Data used with permission of Michael McDowell, School of Dentistry, Royal Victoria Hospital, Belfast

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Tablet Discolouration

The problem:

Pharmaceutical tablets must have an attractive and

homogeneous appearance.

A client presented tablets which were a slightly

different colour to the ‘good’ tablets. The question:

Can CT determine the reason for tablet

discolouration?

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Tablet Overview

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Tablets – With Highlighted Regions

Good Bad

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Tablets – Packing Density Analysis

‘Good’ Material % Average Material % Region 1 97 97 Region 2 97 Region 3 97 Region 4 97 ‘Bad’ Material % Average Material % Region 1 95 93.75 Region 2 93 Region 3 93 Region 4 94

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Outcome

One sample shows a different packing density to the

ther.

Next step: confirmation from alternative source.

“Appearance of the model tablets depended

significantly on the compression pressure” - Matsumoto et Al. Impact of compression pressure

n tablet appearance. International Journal of

Pharmaceuticals 341 (2007) 44-49

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Powder Application Demonstration

Demonstrate the capabilities of x-ray micro-computed tomography to analyse powders.