FEASIBILITY STUDY OF AN ELECTRON FEASIBILITY STUDY OF AN ELECTRON ACCELERATOR BASED PHOTOACCELERATOR BASED PHOTO--NEUTRON NEUTRON

SOURCE SOURCE &&

ITS APPLICATIONS FOR ELEMENTAL CHARACTERIZATION ITS APPLICATIONS FOR ELEMENTAL CHARACTERIZATION and RADIOGRAPHYand RADIOGRAPHY

CARGO SCANNINGCARGO SCANNING

Amar Sinha

High Pressure Physics Division, Bhabha Atomic Research Centre,

Trombay, Mumbai , INDIA

REAL TIME X-RAY DIFFRACTION SYSTEM

FEATURES

-DATA COLLECTION TIME IN SECONDS

-REAL TIME IMAGES

-KINETICS STUDY

-QUICK SCANNING OF PHASE TRANSITION

A CCD based detector for quick detection of pressure induced phase transition

-Amar Sinha, et al - High Pressure Research vol 21, pp 51-64, 2001

3D X-RAY CONE BEAM TOMOGRAPHY

FEATURES

DIRECT 3D RECONSTRUCTION

VOLUME VISUALIZATION

REVERSE ENGINEERING

FAST DATA ACQUISITION

SUITABLE FOR LARGE OBJECT

MICROTOMOGRAPHY

HIGH DYNAMIC RANGE DETECTOR –16 Bit

HIGH SENSITIVITY TO MINOR VARATION IN ATTENUATION COEFFICIENT

Photograph of Al end cap

Photoradiograph of Al end cap

3D reconstructed images

SETUP

Radiograph of a samplemadeup of Al and Al alloy

3D tomographCutaway view

3D reconstruction of Ten turn Potentiometer and Zircloy weld

Schematic

Development and Characterization of a 3D Cone Beam Tomography System -P.S.Sarkar, A.Sinha, Y.kashyap, M.R.More, B.K.Godwal Accepted for publication in Nucl. Instr. Meth. A for publication (2003)

n-scintillation

SCINTILLATION IMAGING TECHNIQUEFOR NEUTRONS

SENSITIVE DUAL STAGE INTENSIFIER + CCD With 6LiF+ZnS

MAKE IMAGES BY COLLECTING SCINTILLATION –ggod for low strength sources

NEUTRON IMAGINGNEUTRON IMAGINGSMALL NEUTRON SOURCESSMALL NEUTRON SOURCES

Pu-Be sources –2x107 n/s

Radiiogrphy assembly L/D =10 FLUX <102

Adding and averagingseveral frames

The aim was to show that one can use even such low strength source for qualitative imaging

Image limited by statistical noise

14 MeV NeutronGENERATOR 108 n/s

Test tube with water

Plastic bolt Possible applicationsPossible applications

Radiography of some Radiography of some inaccesibbleinaccesibble parts , Level of parts , Level of charge filling of bullets etccharge filling of bullets etc

14 14 MeV MeV GeneratorGenerator

A 14-MeV (D,T) neutron generator fabricated and installed in the Purnima reactor vault at BARC is an ideal source for this purpose. 14MeV neutrons are produced when 100-200 µA D+ ion current accelerated up to 300 kV is bombarded on a 10 Citritium target. At present it is capable of producing neutron yield of ~ 3x109 n/s. The actual photograph of the neutron generator is shown in fig.1.

APPLICATION DEVELOPMENTAPPLICATION DEVELOPMENT

2D & 3D NEUTRON TOMOGRAPHY 2D & 3D NEUTRON TOMOGRAPHY (USING REACTOR(USING REACTOR))

0 V l d d i b i d i Fi 11 C i h b

the broken rod.

a b

THERMAL HYDRAULICSTHERMAL HYDRAULICSSTUDIES WITH NEUTRONSSTUDIES WITH NEUTRONS

VISUALIZATION INSIDE METALLIC PIPE AND VOID VISUALIZATION INSIDE METALLIC PIPE AND VOID FRACTION ANALYSISFRACTION ANALYSIS

Besides Besides ––Some security Some security devices such as Cargo devices such as Cargo inspection system inspection system

Portable xPortable x--ray systems ray systems (battery based)(battery based)

Marine Cargo inspectionMarine Cargo inspectionsomesome specific problemsspecific problems

Two specific application areas Two specific application areas Unexploded ammunitionUnexploded ammunition

Recently there have been Recently there have been instances of a large consignment of instances of a large consignment of unexploded ammunition being unexploded ammunition being imported as scrap by some iron imported as scrap by some iron scrap dealers scrap dealers

Several hundred Kg of explosive Several hundred Kg of explosive imported as marine cargo and imported as marine cargo and used for terrorist activityused for terrorist activityMoreMore-- narcotics???narcotics???

Can Electron accelerators Can Electron accelerators based photo neutron sources based photo neutron sources be used for elemental be used for elemental characterization??characterization??

What about the enormous high What about the enormous high energy Xenergy X--ray photons which ray photons which are the source of neutrons are the source of neutrons itself itself --backgroundbackground

Reason for exploring Reason for exploring this possibilitythis possibility

Electron accelerators are being Electron accelerators are being used for high energy Xused for high energy X--ray source ray source at several Ports for cargo at several Ports for cargo inspectioninspection

Can an additional neutron Can an additional neutron converter be added to it to make converter be added to it to make neutron investigation possible neutron investigation possible ––if it if it can be used it provides cheaper can be used it provides cheaper solution and can act as second solution and can act as second check with no extra generatorcheck with no extra generator

What should be characteristics of What should be characteristics of such accelerators ??such accelerators ??

To do this To do this ––Microtron Microtron as test bed?as test bed?

We are examining this possibility by We are examining this possibility by using a high repetition rate pulsed using a high repetition rate pulsed MicrotronMicrotron which essentially an which essentially an electron accelerator.electron accelerator.Why Why microtronmicrotron????

This source has been installed at This source has been installed at One of the universities in India and One of the universities in India and we are using this source for we are using this source for designing neutron converter and designing neutron converter and using it as a test bed for developing using it as a test bed for developing various applications including for various applications including for bulk cargo inspectionbulk cargo inspection

ELEMENTAL CHARACTERIZATION ELEMENTAL CHARACTERIZATION USING PROMPT GAMMAUSING PROMPT GAMMA

Fast Neutrons

Thermal Neutrons

10 µs 90 µs

Reactions

Gamma

Elements

(n,n’γ), (n,pγ)

Prompt

C, O

(n,γ)

Prompt

H, S, Cl, Fe, N ...

Activation(n,α), (n,p)

Delayed

O, Al, Si

Slow Neutron Nucleus

ExcitedNucleus

FastNeutron Nucleus

Gamma Ray

ExcitedNucleus

Gamma Ray

Neutron Capture Inelastic Scattering

This talk will focus on design This talk will focus on design aspects and optimisation of aspects and optimisation of neutron source and then we neutron source and then we discuss its application for cargo discuss its application for cargo inspection.inspection.

We are still doing Monte We are still doing Monte carlo carlo simulation of possible simulation of possible application of such neutron application of such neutron sources for cargo inspectionsources for cargo inspection--so only discussion on feasibilityso only discussion on feasibility

of design of such sourceof design of such source

DESIGN AND APPLICATION OF DESIGN AND APPLICATION OF ACCELERATOR BASED NEUTRON ACCELERATOR BASED NEUTRON

SOURCESOURCE

MicrotronMicrotron is a compact cyclic electron is a compact cyclic electron accelerator. accelerator.

Though not really portable but can be Though not really portable but can be easily relocated and because of its easily relocated and because of its simplicity and high efficiency of design it simplicity and high efficiency of design it can be used as an R&D tool for can be used as an R&D tool for developing many applications. developing many applications.

The Variable Energy The Variable Energy MicrotronMicrotron at at Mangalore University facilitates Mangalore University facilitates acceleration of electrons up to 9.0 acceleration of electrons up to 9.0 MeVMeVwith RF cavity type I and 12 with RF cavity type I and 12 MeVMeV with with redesign of RF cavity type. redesign of RF cavity type.

We have been associated with design of We have been associated with design of neutron converter for neutron converter for microtronmicrotron..

DESIGN OF MICROTRON BASED DESIGN OF MICROTRON BASED NEUTRON SOURCE AND NEUTRON SOURCE AND

APPLICATIONSAPPLICATIONS

PARAMETERSPARAMETERSElectron beam Electron beam -- 99--12 MeV12 MeVcurrent current --40mA(peak), 3040mA(peak), 30µµA (avg..)A (avg..)Pulse width Pulse width -- 3 3 µµssPulse repetition rate: 250 Hz(max)Pulse repetition rate: 250 Hz(max)Bremsstralung Target Bremsstralung Target --tantalumtantalum

This This microtronmicrotron is already being used for is already being used for electron and photon irradiationelectron and photon irradiationOur task has been to use photons from it to Our task has been to use photons from it to produce photoproduce photo--neutron and look for neutron and look for possible applications possible applications ––pulsed & pulsed & continuous (250 Hz)continuous (250 Hz)

Be target design and optimizationBe target design and optimizationSimulation of assembly using MCNPSimulation of assembly using MCNPDevelopment of applicationsDevelopment of applications-- thermal neutron thermal neutron radiography, elemental characterization, fast radiography, elemental characterization, fast neutron radiographyneutron radiography

TargetTarget-- BeBe--Uranium Uranium compositecomposite

our design 4cm Be in front our design 4cm Be in front optimum+1cm Uoptimum+1cm U

expected yield of neutron for 9expected yield of neutron for 9 MeVMeVelectron with optimized target design : electron with optimized target design : ~ 10~ 101010n/s for 250 Hz operationn/s for 250 Hz operation

For 12For 12 MeVMeV: ~4x10: ~4x101010n/sn/s

MICROTRON BASED NEUTRON SOURCEMICROTRON BASED NEUTRON SOURCE

BeTantalum

electron-photon- neutron

e

nγ

Why Be?

Are there other combinations-composite Target?

high energy electrons to produce photons

- Photons then produce neutrons through photo-neutron reaction

-

Why Be?

Reason –Cross-section and large flux of photons just above neutron production threshold

-If using low energy accelerator Be is the only choice –Lower Cross-section is

compensated by utilization of large softer spectrum between 1.66 and 3 MeV.

Be is suited for low energy Be is suited for low energy electron acceleratorelectron accelerator

For Higher ElectronEnergy –use composite Target Be for lower partOf spectrum and U forHigher energy component

At Higher Energies Be photo-neutron cross-section lower by several factors compared to other elements

MAJOR STEPSMAJOR STEPS

PHOTON YIELD, ANGULAR AND PHOTON YIELD, ANGULAR AND ENERGY SPECTRUMENERGY SPECTRUM--EGS OR MCNPEGS OR MCNP

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0

1E-3

0.01

0.1

1

Pho

ton/

Mev

/sr/e

lect

ron

Photon energy(Mev)

0 to 5 deg5 to 10 deg10 to 15 deg15 to 30 deg30 to 45 deg45 to 90 deg

Table forBe Angular Distribution

Keep Target near Be to intercept maximum photon flux

1.621.922.052.2145-90o

4.885.535.776.0930-45o

9.7910.4910.7011.0715-30o

17.7918.1918.3818.6110-15o

25.9225.8525.6925.725-10o

40.0038.0237.4036.300-5o

12MeV10MeV9 MeV8 MeV

Photon intensity in % for different energy electrons

Polar angle

More than 50% of photons are in forward direction

Energy range of photon(Mev) Fraction

0-1.7 0.78

1.7-3.1 0.13

3.3-4.7 0.06

4.9-7.5 0.03

Energy DistributionOf photon- 9 MeV

Only about 22% (> 1.7 contribute towards neutronProduction-1.7- 3.1 MeV is highest---Be suited

PhotoPhoto--Neutron ProductionNeutron Production

Major Steps A. 1. Major Steps A. 1. Divide Be Target in several zonesDivide Be Target in several zones2. Transport incident photon flux t2. Transport incident photon flux to o

estimate photon flux and spectrum in these zonesestimate photon flux and spectrum in these zones

3. Find N3. Find Nσφσφ from from σσ supplied by IAEAsupplied by IAEA

4. Transport these neutrons to find neutron4. Transport these neutrons to find neutronproduction from Be production from Be

BB. These Neutrons form initial source for. These Neutrons form initial source forfurther MCNP calculation of further MCNP calculation of

radiography assembly or Activation or Prompt gammaradiography assembly or Activation or Prompt gamma

E- 9 MeV; Rep rate: 50Hz ; Pulse width: 2µsPeak Current:30mA

Thickness of Be Experimental n/Sec

Simulation

2cm 1.4361*109 1.34*109

4cm 2.2866*109 2.25*109

6cm 2.6024*109 2.91*109

8cm 3.0708*109 3.37*109

EXPERIMNTAL VERIFICATIONCr-39 CALIBERATED

THREE MAIN THREE MAIN APPLICATIONSAPPLICATIONS

ELEMENTAL CHARACTERIZATIONELEMENTAL CHARACTERIZATIONCargo scanningCargo scanning

FAST NEUTRON RADIOGRAPHYFAST NEUTRON RADIOGRAPHY ????NEW APPLICATIONSNEW APPLICATIONS

DIGITAL THERMAL NEUTRON DIGITAL THERMAL NEUTRON RADIOGRAPHY RADIOGRAPHY ––University researchUniversity research

We discuss first twoWe discuss first two------------

ELEMENTAL CHARACTERIZATION ELEMENTAL CHARACTERIZATION USING PROMPT GAMMAUSING PROMPT GAMMA

Fast Neutrons

Thermal Neutrons

10 µs 90 µs

Reactions

Gamma

Elements

(n,n’γ), (n,pγ)

Prompt

C, O

(n,γ)

Prompt

H, S, Cl, Fe, N ...

Activation(n,α), (n,p)

Delayed

O, Al, Si

Slow Neutron Nucleus

ExcitedNucleus

FastNeutron Nucleus

Gamma Ray

ExcitedNucleus

Gamma Ray

Neutron Capture Inelastic Scattering

DETECTORS FOR SUCH DETECTORS FOR SUCH APPLICATIONSAPPLICATIONS

Use a gate to open the gamma Use a gate to open the gamma detector just after the pulse of detector just after the pulse of primary gamma is over primary gamma is over --this method this method will avoid direct gamma from neutron will avoid direct gamma from neutron sourcesource

It may also possible to activate short It may also possible to activate short half life elements after repetition of half life elements after repetition of certain no of pulses and thus detect certain no of pulses and thus detect activation of such elements activation of such elements --by by stopping neutron pulsestopping neutron pulse

DETECTOR DETECTOR -- BGOBGO scscintillator/ intillator/ photomultiplier, fast electronics, photomultiplier, fast electronics, gated time window, gamma gated time window, gamma spectrum spectrum analyseranalyser, , deconvolutiondeconvolutionsoftwaresoftware

Shielding design Shielding design –– A major factorA major factor

We are currently in the process of We are currently in the process of Doing MONTE CARLO SIMULATION Doing MONTE CARLO SIMULATION STUDIES for various design aspect.STUDIES for various design aspect.

HighHigh--energy neutron imaging for energy neutron imaging for the inspection of thick objectsthe inspection of thick objects

Goal: detection of cubic-mm-scale defects in shielded low-Z materials

Two 1” poly slabs (unshielded)

10 MeV neutrons 9 MeV electron Bremsstrahlung

Neutron image quality Neutron image quality is comparable to is comparable to conventional xconventional x--ray ray image quality for image quality for unshielded polyunshielded poly..

All features machined into the polyethylene slabs were discernable in the image when the slabs were unshielded

High Energy neutrons High Energy neutrons vsvs 9 MeV x9 MeV x--raysrays

Lanza et al

Two 1” poly slabs shielded by 4” of D-38

Neutron radiograph Neutron radiograph reveals detail in reveals detail in shielded poly and shielded poly and DD--38 pieces now 38 pieces now opaque to x rays.opaque to x rays.

10 MeV neutrons 9 MeV electron Bremsstrahlung

All features present in both the poly slabs and U-238 shielding were still discernable in the image when 4” of shielding was used

Highly shieldedHighly shielded

PORTABLE PORTABLE GENERATORGENERATOR

We do have plan for Developing We do have plan for Developing methods for explosive detectionmethods for explosive detectionWith portable generatorsWith portable generators

PFNA or any suitable technique for PFNA or any suitable technique for Bulk cargo scanningBulk cargo scanning

Development of TNA and FNA Development of TNA and FNA

Polyethylene Be Uranium

Lead

Thermal Neutron Radiography

Polyethylene Be Uranium

Lead

Thermal Neutron Radiography

φth=107

n/cm2/sφth=1X104

n/cm2/s

DETECTOR FOR DETECTOR FOR RADIOGRAPHYRADIOGRAPHY

ELECTRONIC IMAGING OF ELECTRONIC IMAGING OF NEUTRONSNEUTRONS

COOLED CCD+COOLED CCD+66LiF:Zns LiF:Zns scintllatorscintllator

May be operated in gated May be operated in gated mode mode ––off during 2 microoff during 2 micro--sec sec gamma pulse for better S/N gamma pulse for better S/N ratioratio

Production Rates for Low Energies

ONLINE DETECTION OF BULK ONLINE DETECTION OF BULK MATERIALMATERIAL

On Line Bulk Material analyzer On Line Bulk Material analyzer using prompt gamma, Neutron using prompt gamma, Neutron activation analysis (PGNAA)activation analysis (PGNAA)

Ex: elemental composition of (a) Ex: elemental composition of (a) cement raw materials cement raw materials --silicon, silicon, calcium, iron, aluminum, calcium, iron, aluminum, magnesium…(b) coal © copper magnesium…(b) coal © copper oreoreThe measurement chamber to be The measurement chamber to be

designed with different moderating designed with different moderating material (lead, graphite, polyethylene. material (lead, graphite, polyethylene. ..) in order to optimize thermal neutron ..) in order to optimize thermal neutron flux around material being analyzed.flux around material being analyzed.

REAL TIME X-RAY DIFFRACTION SYSTEM

FEATURES

-DATA COLLECTION TIME IN SECONDS

-REAL TIME IMAGES

-KINETICS STUDY

-QUICK SCANNING OF PHASE TRANSITION

-MODULAR DESIGN

A CCD based detector for quick detection of pressure induced phase transition

-Amar Sinha, Alka B. Garg, V. Vijaykumar , B.K. Godwal and S.K. Sikka- High Pressure Research vol 21, pp 51-64, 2001

3D CONE BEAM TOMOGRAPHY

FEATURES

DIRECT 3D RECONSTRUCTION

VOLUME VISUALIZATION

REVERSE ENGINEERING

FAST DATA ACQUISITION

SUITABLE FOR LARGE OBJECT

MICROTOMOGRAPHY

HIGH DYNAMIC RANGE DETECTOR –16 Bit

HIGH SENSITIVITY TO MINOR VARATION IN ATTENUATION COEFFICIENT

Photograph of Al end cap

Photoradiograph of Al end cap

3D reconstructed images

SETUP

Radiograph of a samplemadeup of Al and Al alloy

3D tomographCutaway view

3D reconstruction of Ten turn Potentiometer and Zircloy weld

Schematic

Development and Characterization of a 3D Cone Beam Tomography System -P.S.Sarkar, A.Sinha, Y.kashyap, M.R.More, B.K.Godwal Accepted for publication in Nucl. Instr. Meth. A for publication (2003)

n-scintillation

SCINTILLATION IMAGING TECHNIQUE FFOR NEUTRONS

SENSITIVE DUAL STAGE INTENSIFIER + CCD With 6LiF+ZnS

NEUTRON IMAGINGNEUTRON IMAGINGSMALL NEUTRON SOURCESSMALL NEUTRON SOURCES

Pu-Be sources –2x107 n/s

Radiiogrphy assembly L/D =10 FLUX <102

Adding and averagingseveral frames

The aim was to show that one can use even such low strength source for qualitative imaging

Image limited by statistical noise

14 MeV NeutronGENERATOR 108 n/s

Test tube with water

Plastic bolt Possible applicationsPossible applications

Radiography of some Radiography of some inaccesibbleinaccesibble parts , Level of parts , Level of charge filling of bullets etccharge filling of bullets etc

APPLICATION DEVELOPMENTAPPLICATION DEVELOPMENT

2D & 3D NEUTRON TOMOGRAPHY 2D & 3D NEUTRON TOMOGRAPHY (USING REACTOR(USING REACTOR))

0 V l d d i b i d i Fi 11 C i h b

the broken rod.

a b

THERMAL HYDRAULICSTHERMAL HYDRAULICSSTUDIES WITH NEUTRONSSTUDIES WITH NEUTRONS

VISUALIZATION INSIDE METALLIC PIPE AND VOID VISUALIZATION INSIDE METALLIC PIPE AND VOID FRACTION ANALYSISFRACTION ANALYSIS

14 14 MeV MeV GeneratorGenerator

A 14-MeV (D,T) neutron generator fabricated and installed in the Purnima reactor vault at BARC is an ideal source for this purpose. 14MeV neutrons are produced when 100-200 µA D+ ion current accelerated up to 300 kV is bombarded on a 10 Citritium target. At present it is capable of producing neutron yield of ~ 3x109 n/s. The actual photograph of the neutron generator is shown in fig.1.