Applications in Security

Eamonn CooneySales & Business Development Manager

March 15,2011

Point Detector Overview

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Aviation Security Sector

Baggage Screening

Advances in Detector Applications for Security

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Nuclear Industry Safety & SecurityRadiation Monitoring

Need Detector RequirementMinimal disruption to passenger throughput

Detector must work at high count rates in order to minimize Poisson noise whilst still providing fast measurements.

Ability to scan all types of containerTransparent, translucent, opaqueMetal, coloured glass & cardboard

X ray systems must work at high energy in order to provide for inspection of metal containers. This then requires high quantum efficiency at high energy and therefore high Z detector materials

Non invasive detection and ID of drugs, IEDs, explosives, components of and flammable liquids

Many threat and benign materials have very similar x ray absorption properties. This means not only must the detector precision be very high but also the response of the detector at different flux rates, illumination spectra, temperatures etc. must be calibrated so this precision is not lost.

Low False Alarm Rate Low false alarms rates can be achieved by combining the precision, speed, high quantum efficiency and calibration of the system with algorithm development which makes the systems immune to the ever increasing range of benign materials with potential threat overlaps

Airport Security Threat Detection

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Airport Check in and Baggage Screening

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Importance of accurate and sensitive threat detection

Applications of multi energy to powders and compounds

Absorption difference between powder explosive precursor and benign material cannot be seen by only low energy and high energy measurements

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Powder explosives are a significant problem for dual energy x ray even in a CT modality. Careful mixing can produce identical effective atomic number and density for two point measurement

Th

rea

t- b

en

ign

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X

Energy

X

Y

Energy

Current dual energy detectors:

Only two energiesEnergy thresholds are fixed

CZT detectors:Multiple energy bands

Energy bands electrically configurable

High

Low

Non Spectroscopic Spectroscopic

Indirect and direct conversion

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Aviation Security Scanning Examples

Type B Bottle ScannerCZT based Multispectral X ray Imaging for threat LAGs

Type C & Type D X-ray cabin baggage and checked in baggage scanners employ a range of X-ray technologies including Dual energy X ray, XRD and CT…

Type A systems tend to be invasive e’g.Dip Strips, trace detectors:

Security Detectors Examples 1

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CZT 4” Boule – the starting point for single crystal detectors

CZT Coplanar Grid 10 x 10 x 10 mm³ detector for a compact HR Gamma Ray Spectrometer

Security Detector Examples 2

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CZT Detector: 20 x 20 x 15mm3

11 x 11 pixelsFor security applications

CZT Detector 10 x 10 x 1.5 mm3

1296 pixels 36 x 36 for Airport CT Scanner application

Security Detector Examples 3

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Security Bottle Scanner Single small pixel CZTdetector

IMELDA Pixellated ASIC for aCT Airport Scanner with a CZT16 x16 Array and 500um x 500um pixels

Security Detectors Examples 4

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CZT detector 16 x16 matrix 500um pixels mounted on an ASIC for Spectrometry and Compton Camera applications

Composite of 32 individual pixelsFor a security baggage Scanner

The best detector performance requires high performance ASICs and read out electronics

ASICs & electronics

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Any real detector consists of a material which converts the incoming photons into a materials response and a way of processing the materials response. The matching of electronics design to detector response is essential to avoid artefacts

ASICs & electronics

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Typical problem Artefacts Solutions

Variations of signal response due to position of interaction in the detector.

Different effective gains dependant on position of interaction.

Multi electrode signal capture allowing position of interaction correction.Suitable matching of amplifiers response time to detector response time.

Pile up of analogue signal response.

Changes in spectral response as a function of count rate.

Minimization of analogue response time.Digital post processing of signals to deconvolute pile up.

Multichannel electronics have channel to channel variations in gain, offset and transient response

Ring artefacts in CT. Streaking in projection images.

Multiple layers of channel to channel trimming and calibration.

Charge sharing between pixels

Distortion of spectral response

Real time or list mode charge reconstruction dependant on system count rate.

Safety & Security

Radiation Monitoring

Security & Safety in the Nuclear Industry

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Some applications for High Resolution Gamma Ray Spectrometry

Nuclide identification in high dose areas.

Primary coolant analysis and circuit characterisation

In situ isotope mix. In formation on status

Effluent release monitoring. What is present?

Outage / shutdown fuel replacement: Location,

identification and cause of contamination before and during outages.

Spent fuel storage and waste pond monitoring

Detector Type Resolution@ 662 keV

Cs137

TypicalWeight

OperationalTemperature

0°CCZT <2.0 and <2.5% 60g 0-40°C

HpGe 0.21% 6.8 Kg Cooling required

NaI (Ti) <8% 1.25-2 kg -20°C +50°C

LaBrɜ <4% 1.25-2.0 kg -20°C +50°C

Detector Comparison

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Gamma Ray Spectrometry – recent developments

A compact Gamma Ray Spectrometer measuring only 25mm x 25mm x 64mm and weighing only 60gm. ( Match box size)

High performance gamma ray spectrometer uses an advanced 1cm³ Coplanar Grid CZT detector offering far superior resolution compared to Sodium iodide (NaI) and Lanthanum Bromide (LaBr3) based devices

CPGD CZT Resolution: 1.5-2.5% FWHM @ 662 keV: A viable alternative in many cases to much larger and more expensive Germanium (HpGe) based spectrometers.

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CZT – GR1 Gamma Ray Spectrometer

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81keV

(133Ba)

59.5keV(241Am)

276keV

(133Ba)

303keV

(133Ba)

356keV

(133Ba)

384keV

(133Ba)

662keV

(137Cs)

1173keV

(60Co)

1333keV

(60Co)

Gloved GR-1 was used to identify and measure the radioactivity of scattered debris in high dose areas throughout the plant

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Case Study: Japan Fukushima Disaster

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GR-1 Gloved (Lead encased) Spectrometer at Fukushima

寸法：直径 11cm× 長さ 14.5cm重量： 15kg特徴：常温型高線量率用 γ 線スペクトロメータ

内蔵検出器Kromek GR-1

Fukushima Glove BoxEncasing GR-1

Case Study: Fukushima Reactor Measurements

Measurements taken at the Tokyo Electric Power Company (TEPCO) 1F disaster site

GR1 used to identify radioactivity amongst the debris

Five minutes per location

Gloved GR1Spectrometer performed under high dose radiation > 50mS/hr

High resolution: Cs -137 and Cs -134 radioisotopes clearly identified as the main gamma-ray emission nuclide. The measurement performance exceeded expectations.

Energy range measured: 30-1333keV

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Measure of High Dose rate Concrete Fragmentin Fukushima

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Hand Held Gamma Ray Spectrometers

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Examples

High Detection Sensitivity Handheld SpectrometerWith 2” x 2” NaI Detector<7% FWHM @ 662 keV

Applications

Nuclear First responders

Security screening by police, fire and rescue services

Nuclear installation monitoring

Nuclear accident response

Site surveys

High Resolution Handheld SpectrometerWith 1 cm³ CZT Detector<2% FWHM @ 662 keV

Thank You

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US Operation

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