Combined Fast Neutron and Dual Energy Gamma Ray Transmission (NEUDEG) Measurements to Non-

invasively Assess Materials

Murray BartleImaging Laboratory, GNS Science, Gracefield Rd.,

Lower Hutt, New Zealand

IAEA Co-ordinated Research ProgrammesIAEA RCA Asia Pacific ProgrammeIAEA Expert Missions in S E Asia.

Outline

• Dual beam systems in industry• Neutron gamma transmission• Dual energy x-ray absorption• IAEA activities Asia – Pacific• Fast neutrons and dual energy gamma rays

Incident γ-ray beam

Detector

Transmitted beam

Incident neutron beamproduct

Transmitted beam

DUAL BEAM TRANSMISSION PRINCIPLE

  hydrogenwt%

carbon wt%

nitrogen wt%

oxygen wt%

n(H) per gm EAN

LEAN(approx)

10 10 3 77 6.15 x 1022 7.64*

FAT 15 74 0 11 9.05 x 1022 5.83

Measurement of Meat Fat Content

* includes minerals

NEUGAT LAYOUT

^0.4m

Source (0.2 μg 252Cf)

0.25m

liquid organic scintillator

conveyor

Tank water

Test material

PSD

n

n + g

A. Simultaneous fast neutron and gamma ray transmission from a 252Cf source

Neutron and gamma ray events in the scintillator can be separated by PSD

Fig. 6. The NEUGAT system called ‘Phoebe’ based on a 252Cf source and a 6 litre organic liquid scintillation detector. The source is mounted in the top tank filled with water and the detector is mounted under the conveyor. Neutron and gamma ray events are separated by pulse shape discrimination.

10 20 30 40 50 60

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60

Low density

O High density

LOW AND HIGH DENSITY WOOD CHIPS

high density

low density

chips

chips

NE

UG

AT

WA

TE

R C

ON

TE

NT

(W

T%

)

CALIBRATION WATER (WT%)

difference: neutrons - gamma absorption (counts)v sum of absorptions

0.0

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sum absorption (counts)

dif

fere

nc

e in

ab

so

rpti

on

(c

ou

nts

)polyethylene layers

acrylic layers

water layers

sand layers

NEUGAT

Features of NEUGAT in the context of industrial applications:

1. Including neutrons as one of the beams provides sensitivities to the presence of light elements in materials.

2. Use of neutrons as one of the beams limits the possibility of using imaging.3. The shielding of neutrons in an industrial environment is more difficult that

x-rays or gamma rays.4. Organic detectors with large volumes have moderate cost but need to use

liquid organic scintillators for PSD limits the possibilities in industry due to fire risk.

5. PSD electronics are unreliable in an industrial context.

‘The COALSCAN 2100 is a new configuration in the Dual Energy Transmission (DUET) ash gauges and offers all the accumulated operational experience gained since COALSCANs were first developed, but at a significantly reduced price.’

COALSCAN 2100 - Scantech Australia

Need to be able to resolvethe two gamma ray energygroups in the detector andalso count at high count-rates.

Inorganic scintillators give good energyresolution, but are either expensive (e.g. LaCl3)or slow (e.g. NaI(Tl)) adding cost or providinglimited count-rates

Sizes of detector are limited by cost.

Dual energy photon beams

20 40 60 80 100 120 1400

10

20

30

40

50

XADA detector

x-ray spectrum absorption: low detector absorption: high detector

num

ber

of p

hot

ons

[a.u

.]

energy [keV]

Fig1. The effective LE (red line) and HE (blue line) x-ray energy bands producedin the Eagle DEXA scanner, derived byfiltering the total x-ray spectrum (black line)from the x-ray source at the detector. The two peaks are characteristic x-ray lines; thelower energy peak is Kα and the higherenergy peak is Kβ. The underlying continuousdistribution is from bremsstrahlung radiation.

Fig.2. The Eagle DEXA scanner used in these measurements is located in the Isotope and X-ray Imaging Laboratory, National Isotope Centre, GNS Science, Lower Hutt, New Zealand. (Note: DEXA scanners are also deployed at airports (luggage scanning) and hospitals (in vivo bone density measurement).

B. MEAT SCANNING. Dual energy x-rays resolved in separate detector (arrays)

Highly engineered production scale and speed scanning system

AA=LOW energy detector

BB=filter

CC=HIGH energy detector

AA

CC

BB

Basic components of a dual energy detector element

0 0.2 0.4 0.6 0.8 10

5000

10000

15000

20000

25000

30000Aluminium (Al) Z=13

Polynomial (Aluminium (Al) Z=13)

glass-based scintillators

Polynomial (glass-based scintil-lators)

polycarbonate

Polynomial (polycarbonate)

polystyrene-based scintillators

Polynomial (polystyrene-based scintillators)

mu metal A 75%Ni 25%Fe

Polynomial (mu metal A 75%Ni 25%Fe)

iron strip (Fe) Z=26

Polynomial (iron strip (Fe) Z=26)

mu metal B 75%Ni 25%Fe

Polynomial (mu metal B 75%Ni 25%Fe)

silver (Ag) Z=47

Polynomial (silver (Ag) Z=47)

soda lime glass

Polynomial (soda lime glass)Summed absorptions LE + HE (normalised)

Diffe

renc

e in

abs

orpti

ons L

E - H

E (a

rbitr

ary

units

)

Fig.3 DEXA absorption curves for with a rangeof atomic numbers (elements) or effectiveatomic numbers (compounds/alloys). Asummed absorption of unity correspondsto total absorption of the LE and HE beamin the material.

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LE

-HE

beam

ab

so

rpti

on

LE + HE beam absorption

DEXA Absorption Curves

Acrylic + aluminium layers

Acrylic layers

Polyethylene layers

dry sand

Validation trial March 2006y = 1.015x - 1.396

R2 = 0.997

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100

50 60 70 80 90 100

Laboratory 1

Eag

le F

A

A sample

Linear (A sample)

Fig.4 Meat measurementin meat boxes usingDEXA, Eltham New Zealand

2007 R.W. Purchas, R. Archibald, J.G. West., C.M. Bartle. ‘An evaluation of the EagleTM FA DEXA (Dual energy X-ray absorpiometry) scanner as a method of estimating the chemical lean in cartons of boneless beef’, Food New Zealand, February/March issue.

Food NZ Feb/Mar 2007Fig.5 Meat measurement in bulk meat system based on DEXA.

EAGLE FA Meat Scanning System

Measures fat content of meat (100 – fat percentage equals the chemical lean percentage)

Manufacturing:

Doyle Sails NZ Ltd - Stratis Ice: a new super-light, super-strong sail membrane fabric currently on trial in the America’s Cup – an international first for a New Zealand manufactured fabric.

Meatvision Ltd - The Eagle FA: X-ray technology and specialised software that scans meat batches within the processing chain to determine fat content.

EnaSolar - Solar Inverter: a range of solar inverters for the global market with built in wi-fi and statistics package for tracking data.

Kiwi ingenuity praised as Innovators Awards finalists revealedBy Esther Goh, September 13, 2011 @ 12:10 pmFrom nanofibres to bio-pesticides and magnetic resonance, a handful of companies and individuals have been named the best that Kiwi ingenuity has to offer as finalists in the 2011 New Zealand Innovators Awards.

Team names:

Rob Archibald ANZCO FoodsMurray Bartle GNS ScienceJohn West “Joe Manning “Graham Clarke “Wayne Fergus ANZCO FoodsMatt Gorton “Brian Dougan “Jamie Skinner “

2011

C. Other Dual Beam systems

IAEA New Zealand Contributions to Security and Industrial Applications.

IAEA Asia Pacific

DEXA – dual energy and x-ray absorption

NEUGAT – neutron and gamma-ray transmission

NEUDEG – neutron and dual energy gamma ray (transmission)

International Atomic Energy Meetings 2005 - 2009

The NZ Representative at IAEA Co-operative Research Programme Meetings, Technical meetings (Vienna) and RCA (Regional Co-operative Agreement Meetings Asia Pacific region); 1995-2000 and 2005-2010

•1st Research Co-ordinated Meeting on Neutron-based Techniques for the Detection of Illicit Materials and Explosives, Vienna, Austria, 19-21 April, 2006 ‘Low cost methods of detecting illicit materials and explosives’. C Murray Bartle and William Stephenson, GNS Science, PO Box 31312, Lower Hutt, New Zealand

•1st Technical Meeting on Combined Devices for Humanitarian Demining and Explosive Detection, Padua, Italy, 13-17 November, 2006.‘Advances of Industrial Dual beam X-rays scanners and improved methods for detection of explosives and humanitarian demining’. C Murray Bartle, Chris Kröger, William Stephenson and John G West, National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt, New Zealand

•2nd Research Co-ordinated Meeting on Neutron-based Techniques for the Detection of Illicit Materials and Explosives, Mumbai, India, 12-16 November, 2007. ‘Developing Low Cost Systems for the Detection of Threat Materials’, C Murray Bartle, Chris Kröger and William Stephenson, National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt, New Zealand

•2nd Technical Meeting on Combined Devices for Humanitarian Demining and Explosive Detection, Vienna, Austria, 26-30 November, 2007. ‘Utilising Advances in Industrial Dual Beam X-ray Scanners to create New Capabilities in Humanitarian Demining and Explosive detection’. C Murray Bartle, Chris Kröger, and William Stephenson, GNS Science, PO Box 31312, Lower Hutt, New Zealand. •3rd Research Co-ordinated Meeting on Neutron-based Techniques for the Detection of Illicit Materials and Explosives, Johannesburg, South Africa, November, 2009 ‘Developing Low Cost Systems for the Detection of Threat Materials’, C Murray Bartle and William Stephenson, National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt, New Zealand.

IAEA RCA Asia Pacific

•IAEA/RCA Regional Training Course on Off-belt Analysis of Metalliferous Ores and Cement Quality by NAS, 13-17 October 2008, Beijing, China. ‘Country Report for New Zealand’, C Murray Bartle, Bernard Barry and Frank Bruhn, GNS Science, P.O. Box 31312, Lower Hutt, New Zealand.

IAEA/RCA meeting Bangkok March 2009: Summarising old programme ‘Raising Productivity in the Coal, Mineral and Petrochemical Industries By using Nucleonic Analysis Systems and Radiotracers (RAS/8/107)’ and commence new programme ‘Diagnosing Industrial Multiphase Systems by Process Visualization using Radiotracers and Sealed Sources.

•IAEA/RCA meeting and Beijing May 2010 AGM on New Developments and Adoption of Protocols and Procedures for Industrial Radiotracer and Sealed Source TechnologyChina, Beijing May 2010.

•IAEA Expert missions November/December 2010.

IAEA Group Asia Pacific Bangkok 2009

Diagnosing Industrial Multiphase Systems by Process Visualization using Radiotracers and Sealed Sources (RCA) 2009 -2012

http://penguingrove.com

Protocols on Interwell tracer Quang (VIE), Gao (CPR)

Protocols on Column scan Jaafar (MAL), Siripone (THA)

Protocols on Leak detection, H.E. Sharma (India), Sugiharto (INS)

Protocols on Maintenance & Calibration Khan (PAK), Kasige (SRI)

Concept paper for TC project 2012-2013 Jung (ROK), Bartle (NZL)

AGM on New Developments and Adoption of Protocols and Procedures for Industrial Radiotracer and Sealed Source Technology, Beijing, China, 17- 21 May 2010

D. Simultaneous fast neutron and dual energy gamma ray transmission from a 252Cf source (NEUDEG)

0.4m

source

0.25m

Plastic organic scintillator

conveyor

Tank water

Test material

deployable Pb filter 4.5 mm thick

^

NEUDEG LAYOUT

1. Create two beams by making measurements by processing the total beamwith and without a filter similar to what is done with x-rays DEXA machines.

2. NO PSD required and use is made of a plastic organic scintillator.

http://www-naweb.iaea.org/napc/physics/meetings/3rd-RCM-NBT/Presentations/Bartle.pdf

1. Based on a dual beam fast neutron and gamma ray system. Makes use of asimple physical filtering system like DEXA but avoids use of expensive and difficult-to-applyelectronics used in NEUGAT like pulse-shape-discrimination (PSD). Good functionality isobtained without having to completely separate the fast neutrons and the gamma rays intotwo beams.

2. The detector media is low cost plastic scintillator which can be easily machined andassembled into large systems if required.

3. The electronics is reduced to a simple discriminator and counting system. This is low costand reliable and in principle can be operated from a portable computer.

4. Systems are inherently portable.

5. Most countries have 252Cf sources for other applications such as PGNAA so new methodologies using this source are often practical and extends the applicationsof existing sources.

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fere

nce

wit

ho

ut f

ilter

-w

ith

Pb

filt

er

sum absorptions with + without Pb filter

NEUDEG SYSTEM (Difference in absorption : without Pb filter -with Pb filter) v (sum of absorptions)

Poly layers

acrylic layers

water layers

sand layers

c.f. DEXA

DEXA - 'Banana' curves

0.00.20.40.60.81.01.21.41.6

0.0 0.2 0.4 0.6 0.8 1.0LE + HE beam absorption

LE

- H

E b

eam

ab

so

rpti

on

Acrylic + aluminiumlayers

Acrylic layers

Polyethylene layers

dry sand

NEUDEG

http://www-naweb.iaea.org/napc/physics/meetings/3rd-RCM-NBT/Presentations/Bartle.pdf

Application of a NEUDEG System used in the reverse sense.

‘An Efficient Directional Fast Neutron Sensor for a Mixed Radiation Field.’ Radiation Measurements in press, C.M. Bartle and G.V.M. Williams.www.sciencedirect.com/science/journal/aip/13504487

1. Detects fast neutrons in a mixed radiation field2. Directional detector as only the fast neutrons and gamma rays passing through

the filtering system contribute to the calculation, other radiations beingsubtracted out.

Uses of directional detectors of fast neutrons in a mixed radiation field;

1. Controlled fusion neutron imaging (Igushi etal., 2001),2. Nuclear fuel safety research (Kaneko et al., 1997),3. Imaging of solar neutrons and detecting special nuclear materials (SNMs) (Bom,

2009; Bowden et al., 2009; Braver etal., 2006; Srikrishna, Chari and Tisch, 2005)4. Variety of applications in nuclear science (Yamanishi, 2005).

Bowden (2009 estimates) that the reduction of background through use of a directional fast neutron detector could increase the detection range of some special nuclear materials from 7 m to 70 m.

Summary: NEUDEG systems in development

1. Use of a simple physical filtering system (like DEXA approach for x-rays) but applied toa Cf-252 source defines two useful beams for product assessments and avoids useof expensive and industrially unproven electronics needed for NEUGAT e.g. avoids pulseshape discrimination (PSD) electronics. Good functionality is obtained without having to completely separate the fast neutrons and the gamma rays in the two beams. Effectivelythe electronics is reduced to a simple discriminator and counting system that in principle canbe operated from a portable computer.

2. The detector media is low cost plastic scintillator which can be easily machined andassembled into large systems if required.

3. Systems are inherently portable.

4. Most countries have 252Cf sources for other applications such as PNGNAA (promptneutron gamma neutron activation analysis . New methodologies using this source extends the value of the investment in this source.