applications in security eamonn cooney sales & business development manager march 15,2011
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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
NOVA R&D
833 Marlborough Avenue
Suite 200
Riverside
CA 92507-2133
USA
T: +1 (951) 781 7332
F: +1 (951) 781 4858
E: sales@novarad.com
W: www.novarad.com
Kromek Headquarters
NETPark
Thomas Wright Way
Sedgefield
County Durham
TS21 3FD
UK
T: +44 (0) 1740 626060
F: +44 (0) 1740 626061
E: sales@kromek.com
W: www.kromek.com
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