IN SITU GAMMA SPECTROMETRY (1995-2010)...Nuclear Technology Laboratory A r i s t o t l e U n i. o f T h e s s a lo n i k i N u c l e a r T e c h. L a b . IN SITU GAMMA SPECTROMETRY

Nuclear Technology LaboratoryNuclear Technology Laboratory

Aristotle Uni. of Th e

s sa loni k i

N uc l e

a r T e c h

. L a b .

IN SITU GAMMA SPECTROMETRY(1995-2010)

Alexandros CLOUVAS , Stelios XANTHOS ,Georgios TAKOUDIS , Michalis ANTONOPOULOS-DOMIS

and Joelle GUILHOTNuclear Technology Laboratory

Aristotle University of ThessalonikiGR-54124 Thessaloniki /Greece



s sa loni k i

N uc l e

a r T e c h

. L a b .

CONTENTS

• Few words about our research group• some theory about in situ gamma

spectrometry• Presentation of the major results



s sa loni k i

N uc l e

a r T e c h

. L a b .

ARISTOTLE UNIVERSITY OF THESSALONIKIARISTOTLE UNIVERSITY OF THESSALONIKI



s sa loni k i

N uc l e

a r T e c h

. L a b .

ThessalonikiThessaloniki

Greek and Roman monumentsGreek and Roman monuments



s sa loni k i

N uc l e

a r T e c h

. L a b .



FACULTIESFACULTIES

PhilosophyPhilosophy

TheologyTheology

Law, Economic and Law, Economic and Political SciencesPolitical Sciences

AgricultureAgriculture

Forestry and Forestry and NaturalNatural

EnvironmentEnvironment

Veterinary Veterinary MedicineMedicine

MedicineMedicine

DentistryDentistry

Fine ArtsFine Arts

Biggest University in GreeceBiggest University in Greece90 000 undergraduates90 000 undergraduates

8 000 postgraduates8 000 postgraduatesteaching and research staff: 2 304teaching and research staff: 2 304

Covers all disciplinesCovers all disciplinesEducationEducation

FACULTIESFACULTIES

SciencesSciences EngineeringEngineering

Independent SchoolsIndependent Schools••School of PharmacySchool of Pharmacy••School of Physical Education and School of Physical Education and

Sports SciencesSports Sciences••School of Physical Education and School of Physical Education and

Sports Sciences Sports Sciences ••School of Journalism and Mass Media School of Journalism and Mass Media

StudiesStudies



s sa loni k i

N uc l e

a r T e c h

. L a b .

Faculty ofFaculty ofEngineeringEngineering

Civil EngineeringCivil Engineering

ArchitectureArchitecture

Rural and Surveying Engineering Rural and Surveying Engineering

Mechanical EngineeringMechanical Engineering

Electrical and Computer EngineeringElectrical and Computer Engineering

Chemical EngineeringChemical Engineering

Schools of:Schools of:

Mathematics, Physics and Mathematics, Physics and Computational SciencesComputational Sciences

UrbanUrban--Regional Planning and Regional Planning and Development EngineeringDevelopment Engineering



s sa loni k i

N uc l e

a r T e c h

. L a b .School of Electrical and Computer EngineeringSchool of Electrical and Computer Engineering

Electrical EnergyElectrical EnergyElectronic and Electronic and

Computer Engng Computer Engng TelecommunicationsTelecommunications

DivisionsDivisions

Laboratories of:Laboratories of:Electrical MachinesElectrical Machines

Power systemsPower systemsHigh VoltageHigh Voltage

Electro technical materialsElectro technical materials

Laboratories of:Laboratories of:ElectronicsElectronics

Automation and RoboticsAutomation and RoboticsInformation Processing and ComputingInformation Processing and Computing

Computing Systems ArchitectureComputing Systems Architecture

Laboratories of:Laboratories of:TelecommunicationsTelecommunications

Nuclear TechnologyNuclear Technology

Undergraduate : national competition (numerus clausus)Undergraduate : national competition (numerus clausus)students admitted to this school have the 2students admitted to this school have the 2ndnd largest marks over all Greek univ. largest marks over all Greek univ.

schoolsschoolsPostgraduate : selection among graduates with diploma mark > 7/Postgraduate : selection among graduates with diploma mark > 7/1010

Admission criteria Admission criteria



s sa loni k i

N uc l e

a r T e c h

. L a b .NUCLEAR TECHNOLOGY LABORATORYNUCLEAR TECHNOLOGY LABORATORY

1 Assistant 1 Assistant ProfessorProfessor

1 Lecturer Fellow1 Lecturer FellowResearch:Research: Environmental Radioactivity (measurements, models)Environmental Radioactivity (measurements, models)Interactions of fast ions with matterInteractions of fast ions with matter

Nuclear reactor safety and diagnosticsNuclear reactor safety and diagnosticsPublications in international journals > 180Publications in international journals > 180

http://nestoras.ee.auth.grhttp://nestoras.ee.auth.gr

Staff : 2 Professors , 1 assistant Professor, 1 Lectrurer , Staff : 2 Professors , 1 assistant Professor, 1 Lectrurer , 2 Research collaborators2 Research collaborators



s sa loni k i

N uc l e

a r T e c h

. L a b .

CONTENTS


spectrometry • Presentation of the major results



s sa loni k i

N uc l e

a r T e c h

. L a b .

EXTR

EMEL

Y LO

WFR

EQUE

NCY

VERY

LOW

FREQ

UENC

Y

VOIC

EFR

EQUE

NCY

LOW

FREQ

UENC

Y

MED

IUM

FREQ

UENC

Y

HIGH

FREQ

UENC

Y

VERY

HIG

HFR

EQUE

NCY

ÐULT

RA H

IGH

FREQ

UENC

YSU

PER

HIGH

FR

EQUE

NCY

EXTR

EMEL

YHI

GH

FREQ

UENC

Y

CENT

IMET

ERW

AVES

MIL

LIM

ETER

WAV

ES

SUBM

ILLI

MET

ERW

AVES

ITUBAND

4ITU

BAND5

ITUBAND

6ITU

BAND7

ITUBAND

8ITU

BAND9

ITUBAND

10ITU

BAND11

ITUBAND

12

FAR

INFR

ARED

INTE

RMED

IATE

INFR

ARED

NEAR

INFR

RED

VISI

BLE

LIGH

TNE

AR U

LTRV

IOLE

TVA

CUUM

ULTR

AVIO

LET

X-RA

YS

GAM

MA

RAYS

SECONDARYCOSMIC RADIATION

GAMMA RAYSPRODUCED BYCOSMIC RAYS

9 10 90 100 900 1 9 10 90 100 900 1 9 10 90 100 900 1 9 10 90 100 9001 9 10 90 100 900 1 9 10 90 1 10 100 1 10 100 1 10 100 1 10eV keV MeV GeVPHOTON ENERGY IN ELECTRON VOLTS (eV)

FREQUENCY IN HERTZ (cycles per second)

HERTZ KILOHERTZ MEGAHERTZ GIGAHERTZ TERAHERTZ

WAVELENGTH IN METERSNON IONIZING RADIATION IONIZING RADIATION

non thermal thermal optical broken bonds(low induced current) (high induced current) (electronic excitation) ( DNA damage)

ELF VF VLF LF MF HF VHF UHF SHF EHF

power lines voice-music AM radio FM radio, TV

microwave oven

light bulbs infrared cameras

X-Ray Machines

radioactiveelements

Electromagnetic spectrum

γ-RA

YS



s sa loni k i

N uc l e

a r T e c h

. L a b .

In situ γ-spectroscopy

METHODS FOR THE DERIVATION OF GAMMA DOSE RATE IN AIR FROM AN IN SITU GAMMA RAY SPECTRA

• “spectrum stripping”method

• “peak area” method (can give also under certain conditions radionuclide concentrations)

050

100150200250300350400

50 550 1050 1550Ενέργεια (keV)

coun

ts/200

0s

Pb-212

Pb-214Tl-208Bi-214

Cs-137

Ac-228K-40



s sa loni k i

N uc l e

a r T e c h

. L a b .

COMPARISON BETWEEN THE 2 METHODS

DELIVERABLE•• Total absorbed gamma dose rate•Total flux energy distribution

ADVANTAGES-DISADVANTAGES• Contribution of each radionuclide to the total dose rate (not possible)• Detector’s geometry knowledge is needed• Source geometry is not needed

DELIVERABLE• Total absorbed gamma dose rate and contribution of each radionuclide to the total gamma dose rate

ADVANTAGES-DISADVANTAGES•Contribution of each radionuclide to the total dose rate ( possible)•Detector’s geometry knowledge is not needed•Source geometry is needed

peak area methodSpectrum stripping



s sa loni k i

N uc l e

a r T e c h

. L a b .

SPECTRUM STRIPPING METHOD

• A count registered by the Germanium detector can be caused by the full or partial absorption of an incident photon or by the passage of a cosmic ray producing a charged particle.

• In order to convert to gamma dose rate the spectrum must be stripped from the partial absorption and cosmic ray events leaving only the events corresponding to the full absorption of a gamma ray.

• The events corresponding to partial absorption in the detector are determined by Monte Carlo simulations for different incident photon energies and angles.Therefore a complete knowledge of the detector geometry is needed.

• Knowing the computed shapes of partial absorption continuum deduced by the Monte Carlo simulation for different incident photon energies and angles ,it is therefore possible to convert the measured in-situ spectra to total incident flux spectra by applying the full absorption efficiency curve of the detector ,which is determined by calibrated point sources and Monte Carlo simulations.

• Having calculated the flux energy distribution ,the absorbed dose rate in air due to gamma radiation is easily deduced .

)()(max

0∑=

=

⋅⋅=

EE

EEEED ρ

µφ α&



s sa loni k i

N uc l e

a r T e c h

. L a b .

1

10

100

1000

10000

100000

0 200 400 600Energy (keV)

coun

ts

Example of the stripping method procedureObject: conversion of measured spectrum to energy flux photons Need for stripping

example

0500

100015002000250030003500400045005000

0 500 1000 1500 2000 2500 3000Energy (keV)

coun

ts

experimentalstripped

0500

100015002000250030003500400045005000

0 500 1000 1500 2000 2500 3000Energy (keV)

coun

ts

1

10

100

1000

10 100 1000 10000Energy (keV)

cpm/

(γ cm

-2 s-1

)

I-131 (experimental)simulated 0

0.01

0.02

0.03

0.04

0.05

0.06

0 500 1000 1500 2000 2500 3000Energy (keV)

gamm

a/(cm2 s

)



s sa loni k i

N uc l e

a r T e c h

. L a b .

Simulation of the HPGe detectorManufacturer’s draft scheme HPGe as was simulated by Monte Carlo



s sa loni k i

N uc l e

a r T e c h

. L a b .

Efficiency of the HPGe detector1.85 MBq (131I)

r =2 mHPGe

where φ = unscattered flux incident to the detector (γ cm-2 s-1)S = intensity of the source (γ s-1)r = distance between source and the detector (cm)µ = attenuation coefficient in air for the specific energy

24 rπeSφ

µr

⋅

⋅=

−

1

10

100

1000

10 100 1000 10000Energy (keV)

cpm/

(γ cm

-2 s-1

)

I-131 (experimental)simulated



s sa loni k i

N uc l e

a r T e c h

. L a b .

Spectrum stripping Energy flux distribution

)(EEρµα⋅Multiply by

Absorbed dose rate energy distribution

)()(max

0∑=

=

⋅⋅=

EE

EEEED ρ

µφ α&

Total absorbed dose rate

summary for the spectrum stripping method



s sa loni k i

N uc l e

a r T e c h

. L a b .

PEAK AREA METHOD

This method was introduced by Beck et al.(HASL 258,1972) Based on this method, Helfer and Miller (Health Physics 55,15,1988)derived simple calibration factors (for the outdoor measurements) which convert the measured full absorption peak count rate to activity in the soil and dose rate in air. The only parameters that are needed are the efficiency and the crystal dimensions ofthe Ge detector used.

Over the years, a number of investigators have adopted and modified the technique (for a review, see ICRU report 53. Clouvas et al.Health Physics 79,274,2000 extended this technique for measurements in an indoor environment and particularly in case of masonry structure.



s sa loni k i

N uc l e

a r T e c h

. L a b .

GAMMA DOSE RATE DETERMINATION BY THE “peak area method”

• The procedure starts with the measurement of an indoor or

outdoor gamma spectrum.

• What is directly deduceddirectly deduceddirectly deduceddirectly deduced by the in situ gamma spectrometry

measurement is the numbernumbernumbernumber NNNN of counts in each photopeak per

unit of time (in counts per minute)

• For each photopeak the dose rate in air due to unscattered

photons (primary photons of energy energy energy energy EEEE) is• is the mass absorption coefficient

• εεεε is the efficiency :peak count rate (in counts per minute)

per unit uncollided flux (photons cm-2

s-1

) for a parallel beam

of gamma rays of energy E that is incident-normal to the

detector face.

0

500

1000

1500

2000

2500

3000

3500

0 500 1000 1500 2000 2500 3000Energy (keV)

coun

ts/200

0s

208Tl

40K214Pb

214Bi

212Pb

208Tl

212Bi

137Cs228Ac

ρµε /)/()( ap NEED ××=&

)(Eµ



s sa loni k i

N uc l e

a r T e c h

. L a b .

“peak area” method(calibration factors for outdoor environment)

Calibration equation

fN :

0N : peak count rate (cpm) for a parallel beam of gamma rays of the same energyincident-normal to the detector’s face

φ : Unscattered flux at a specific energy 1 m above ground

Α : Concentration of the radionuclide in soil (Bq/kg)D& : Absorbed dose rate in air (nGy/h) due to gamma radiation of a specific radiocuclide

Total absorption peak count rate (cpm) in the spectrum at the energy of a particularnuclide gamma transition

AN

NN

AN ff φ

φ ⋅⋅=0

0D

NNN

DN ff

&&

φφ ⋅⋅=0

0



s sa loni k i

N uc l e

a r T e c h

. L a b .

Angular correction

• In an in-situ outdoor or indoor -spectrometry measurement the incident radiation is not just a parallel flux normal to the detector’s face but has all angles of incidence.

• Angular response of the detector is not a critical factor at least up to 120o of incidence

00.20.40.60.8

11.2

0 50 100 150 200angle (in degrees)

coun

ts (n

orma

lized

at 0o

)

I-131 measured (364 keV)Geant (364 keV)Geant (1 MeV)



s sa loni k i

N uc l e

a r T e c h

. L a b .

Detector efficiency ε (Ε)• As in the stripping method ε(Ε) is determined by point sources or/and Monte Carlo simulations.

• Alternatively, with a good approximation the generic factors of Helfer and Miller (Health Physics 55,29,1988) can also be used.

1

10

100

1000

10 100 1000 10000Energy (keV)cp

m/(γ

cm-2

s-1)

I-131 (experimental)simulated



s sa loni k i

N uc l e

a r T e c h

. L a b .

Unscattered flux equation for uniform distribution of radionuclides in soil

s

s

s

zh

d

ee

S

ss

s

ρ

ωρµ

φ

ωρ

ρµ

ωρ

ρµ

αα

α

⋅

−⋅

⋅−=∫

−

−

2)(

11

0

0

Section of an external space in spherical coordinates

where• S0 : Intensity of the source in photons/cm3 s• z : depth till the source is distributed• ω : cosθ• ρs : soil’s density• µs/ρs : mass attenuation coefficient in soil• ρα : air’s density• µα/ρα : mass attenuation coefficient in air• h : detector’s distance from soil

h/ωr h

z

θ

Detector



s sa loni k i

N uc l e

a r T e c h

. L a b .

Simulation of 2π geometry

Simulation of 2π geometry (MCNP code). On the right, zoom in the detector’s area can be seen



s sa loni k i

N uc l e

a r T e c h

. L a b .

Build up factor definition

••The dimensionless build up factor B can be calculated if the The dimensionless build up factor B can be calculated if the geometry of the outdoor or indoor environment is knowngeometry of the outdoor or indoor environment is known••Required: model of outdoor or indoor environmentRequired: model of outdoor or indoor environment

� The total absorbed dose rate in air from a radionuclide can be expressed as a sum of the absorbed dose rate due to unscattered photons and scattered photons in the indoor or outdoor environment. (1)

�Relation (1) can be rewritten as

�The expression within the parenthesis is termed the dose buildup factor B.

spt DDD &&& +=

)1( pspt DDDD &&&& +×=

BDD pt ×= &&



s sa loni k i

N uc l e

a r T e c h

. L a b .

2π geometry conclusions� The methodology used for the derivation of the gamma dose rates from the in situ gamma ray spectra is the one introduced by Beck et al. Based on this method, simple calibration factors (for the outdoor measurements) were deduced which convert the measured full absorption peak count rate to activity in the soil and dose rate in air.

� The only parameters that are needed are the efficiency and the crystal dimensions of the Ge detector used.

�it can be considered that the Ge detector has a uniform response over angles at least up to 120o of incidence

�Alternatively, with a good approximation the generic factors of Helfer and Miller can also be used. The only parameters that are needed are the efficiency and the crystal dimensions of the Ge detector used.



s sa loni k i

N uc l e

a r T e c h

. L a b .

Simulation of 4π geometry

x

y

z

ElementContribution to

weight composition (%)O 51.35Al 14.3Fe 0.9Si 32.25Ti 1.2

Weight composition of brick.

ElementContribution to

weight composition (%)O 53.1Al 3.4Fe 1.4Si 33.8Ca 4.4K 1.3Na 1.6H 1.0

Weight composition of concrete.

A’ way of simulation of an indoor space(massive brick)

Β’ way of simulation of an indoor space(brick with holes: 7cm material, 6 cm air,

7 cm material)



s sa loni k i

N uc l e

a r T e c h

. L a b .

Build up factors for 4π geometry

0.51

1.52

2.53

3.54

0 1000 2000 3000 4000Energy (keV)

Dose

total/D

ose u

nsca

ttered

wall thickness 10cmwall thickness 20cmwall thickness 30cm

0.51

1.52

2.53

3.54

0 1000 2000 3000 4000Energy (keV)

Dose

total/D

ose u

nsca

ttered room dimensions 4X4X3, walls 20cm

room dimensions 4X4X3, walls 7+6+7 cm

Dose build up factor B for three different wall thickness (10 cm, 20 cm and 30 cm). The dimensions of the room used for this calculation were 4X4X3 m and the thickness of floor and ceiling was 0.2 m.

Dose build up factor B calculation for the same room dimensions as before. The wall thickness is 20 cm. In the upper curve the building material of the wall is only brick and in the lower curve the wall is modeled a sum of three slabs (7 cm brick + 6 cm air + 7 cm brick).



s sa loni k i

N uc l e

a r T e c h

. L a b .


0.51

1.52

2.53

3.54

0 1000 2000 3000 4000Energy (keV)

Dose

total/D

ose u

nsca

ttered

wall thickness 20cm, room's dimensions 4X4X3wall thickness 20cm, room's dimensions 2X2X3wall thickness 20cm, room's dimensions 3X3X3

0.5

1

1.5

2

2.5

3

3.5

0 1000 2000 3000 4000Energy (keV)

Dose

total/D

ose u

nsca

ttered wall thickness 10cm, densities ρ =2.2

wall thickness 10cm, densities ρ =1.8wall thickness 10cm, densities ρ =1.4wall thickness 10cm, densities ρ =1

b

bb

b

Dose build up factor B for different room dimensions Influence of the density of the bricks (ρb) to the build up factor B.



s sa loni k i

N uc l e

a r T e c h

. L a b .


0.51

1.52

2.53

3.54

0 1000 2000 3000 4000Energy (keV)

Dose

total/D

ose u

nsca

ttered

same photon emission from walls ceilling and floorphoton emission only from the floor 0

0.51

1.52

2.53

3.54

4.55

0 1000 2000 3000 4000Energy (keV)

Dose

total /

Dose

unsc

attered Beck et al. (1972)

present work

Dose build up factor B for two different gamma emission fields. In the upper curve (circles) the photons are emitted only from the floor (the four walls and ceiling are just scattering medium). In the lower curve (squares) the photons are emitted from the four walls, floor and ceiling.

Comparison between the indoor dose build up factors calculated in the present work with those deduced for the outdoor environment by the calculations of Beck et al. (1972)



s sa loni k i

N uc l e

a r T e c h

. L a b .

4π geometry conclusions

�The build up factor B does not depend strongly on parameters such as a)dimensions of the rooms, b)the thickness of walls, c)the density of the building materials, and d)the gamma source geometry.

�If only approximate results are desired it is possible to use those factors derived for a half-space geometry also for the indoor environment. In the case of a masonry structure this approach is adequate, due to the fact that the ratio of primary to scattered flux is approximately the same for the two environments

�Total gamma dose rates can be directly deduced from in situ gamma spectra using a “spectral stripping method” which does not require any assumptions concerning the source geometry



s sa loni k i

N uc l e

a r T e c h

. L a b .

Build up and Conversion factorsNuclide Energy

(keV) B C B CUranium series214Pb 351.932 3.21 0.57 2.87 0.57214Bi 609.312 2.57 0.19 2.35 0.20

Thorium series212Pb 238.632 3.64 0.90 3.25 0.90208Tl 583.191 2.62 0.14 2.39 0.16212Bi 727.33 2.46 0.47 2.23 0.48228Ac 911.204 2.31 0.28 2.07 0.28137Cs 661.657 2.52 1.00 2.30 1.0040K 1460.83 1.99 1.00 1.80 1.00

outdoor indoor

Nuclide Energy outdoor indoor

(keV)DRCF

(nGy/h per gammaunscattered cm-2 s-1)DRCF

(nGy/h per gammaunscattered cm-2 s-1)Uranium series214Pb 351.932 267 219214Bi 609.312 165 143

Thorium series212Pb 238.632 368 288208Tl 583.191 342 287212Bi 727.33 1443 1212228Ac 911.204 332 281137Cs 661.657 28 2640K 1460.83 43 39

Photon energies used for the determination of the indoor and outdoor absorbed gamma dose rates, their associated radionuclides as well as the corresponding Build up factor B and the contribution C to the dose rate due to all photon energies of each radionuclide

Dose rate conversion factor DRCF



s sa loni k i

N uc l e

a r T e c h

. L a b .

CONTENTS


spectrometry • Presentation of the major results



s sa loni k i

N uc l e

a r T e c h

. L a b .

TURKEY

BULGARIA

F.Y.R.O.M.

ALBANIA

TD100.7 ±31.1R57.0-155.7U25.1%Th37.8%K36.9%Cs 0.1%

TD52.3 ±7.3R41.7-62.3U23.1%Th35.6%K40.8%Cs 0.6%

TD82.5 ±25.8R34.0-120.4U23.9%Th35.1%K41.0%Cs 0.0%

TD81.9 ±19.0R40.1-121.0U22.5%Th37.0%K40.5%Cs 0.0%

TD82.8 ±37.6R30.6-157.4U25.5%Th43.2%K25.7%Cs 0.2%

TD53.1 ±28.9R19.0-113.1U18.2%Th30.1%K21.8%Cs 0.2%

TD71.5 ±24.4R42.4-124.3U32.3%Th34.5%K33.2%Cs 0.0%

TD69.9 ±17.0R51.3-104.0U25.4%Th31.1%K43.3%Cs 0.2%

TD83.3 ±16.0R63.7-114.6U31.5%Th38.2%K30.3%Cs 0.0%

TD59.6 ±12.8R33.6-76.8U26.7%Th33.7%K39.2%Cs 0.4%

TD68.7 ±9.3R55.-86.U30.6%Th34.1%K35.3%Cs 0.0%

67

TD63.3 ±12.3R48.1-79.1U23.7%Th31.1%K45.2%Cs 0.0%

TD85.0 ±29.0R46.9-139.2U22.8%Th35.6%K41.7%Cs 0.0%

TD65.5 ±19.5R36.1-114.9U27.7%Th34.0%K37.2%Cs 1.1%

TD41.0 ±9.0R26.4-51.3U28.9%Th30.4%K40.0%Cs 0.8% TD48.6 ±5.3

R39.9-57.4U24.8%Th29.7%K44.7%Cs 0.8%

TD19.5 ±3.3R14.8-22.5U36.6%Th26.8%K36.7%Cs 0.0%

TD33.5 ±8.7R21.3-47.9U37.3%Th29.3%K32.8%Cs 0.7%

TD30.5 ±5.4R23.3-38.2U29.6%Th34.4%K35.8%Cs 0.2%

TD22.4 ±8.6R10.8-36.2U33.4%Th30.0%K36.6%Cs 0.1%

TD30.8 ±6.3R20.8-42.5U34.4%Th30.5%K35.1%Cs 0.1%

TD39.8 ±11.2R24.4-69.3U25.9%Th34.8%K39.0%Cs 0.4%

TD49.3 ±9.4R30.9-72.9U22.4%Th33.6%K43.7%Cs 0.4%

TD25.6 ±6.5R16.3-37.9U38.3%Th29.0%K32.3%Cs 0.4%

TD60.5 ±9.2R48.-78.6U32.7%Th34.3%K32.8%Cs 0.2%

6

TD20.6 ±5.7R16.0-30.3U46.9%Th24.6%K28.5%Cs 0.0%

TD36.8 ±9.0R20.-50.0U23.2%Th33.2%K42.2%Cs 1.4%

6TD25.8 ±9.5R13.7-50.3U44.8%Th24.9%K30.1%Cs 0.2%

TD36.7 ±11.6R16.2-56.9U31.2%Th30.4%K37.7%Cs 0.6%

TD59.5 ±12.1R29.9-75.2U24.2%Th29.5%K45.6%Cs 0.7%

TD48.4 ±12.8R29.9-68.7U26.6%Th32.6%K40.9%Cs 0.0%

TD53.1 ±6.8R45.1-62.7U23.1%Th35.7%K41.2%Cs 0.0%

TD59.2 ±13.3R18.1-98.7U25.4%Th34.9%K39.0%Cs 0.8%

TD45.5 ±8.1R39.2-62.9U24.3%Th37.2%K38.5%Cs 0.1%

TD60.3 ±9.0R47.5-79.4U25.4%Th33.4%K40.8%Cs 0.5%

TD25.7 ±3.0R23.2-30.8U38.0%Th29.7%K32.2%Cs 0.2%

TD39.2 ±14.1R14.8-71.7U36.9%Th32.9%K30.0%Cs 0.1%

TD75.5 ±9.3R66.2-84.9U28.4%Th39.9%K31.3%Cs 0.4%

TD35.9 ±9.7R27.2-49.3U39.6%Th30.8%K29.6%Cs 0.0%

TD23.9 ±7.2R7.8-53.7U30.8%Th33.6%K35.3%Cs 0.3%

TD32.6 ±9.7R22.2-52.8U41.7%Th29.8%K28.5%Cs 0.0%

TD31.9 ±14.4R12.6-71.6U39.9%Th27.0%K32.8%Cs 0.3%

TD41.7 ±8.7R29.9-56.3U36.8%Th 32.7%K30.5%Cs 0.0%

TD38.7 ±6.0R32.7-46.9U66.3%Th15.1%K18.5%Cs 0.0%

TD34.7 ±9.4R20.2-54.2U38.8%Th28.1%K33.1%Cs 0.0%

TD24.7 ±5.0R17.7-33.3U33.2%Th29.8%K36.7%Cs 0.2%

TD26.4 ±4.9R21.9-34.6U35.4%Th27.8%K36.1%Cs 0.7%

TD28.6 ±10.8R17.9-54.4U48.6%Th23.5%K27.3%Cs 0.6%

TD45.7 ±3.2R41.7-49.5U47.9%Th28.3%K23.1%Cs 0.6%

TD21.9 ±8.1R15.2-35.6U43.8%Th27.6%K28.6%Cs 0.0%

TD42.4 ±6.6R34.8-51.0U44.4%Th30.8%K24.7%Cs 0.1%

TD24.1 ±4.9R18.4-30.4U50.7%Th26.5%K22.8%Cs 0.0%

TD38.2 ±12.6R24.3-56.0U50.1%Th26.1%K23.8%Cs 0.0%

TD29.7 ±7.0R17.2-45.1U40.7%Th30.2%K29.0%Cs 0.1%

TD27.5 ±10.6R14.7-51.3U47.3%Th27.0%K25.4%Cs 0.3%



s sa loni k i

N uc l e

a r T e c h

. L a b .

TURKEY

BULGARIA

F.Y.R.O.M.

ALBANIA

TD 80.8±16.5R 62.6-107.7U 24.7%Th 38.7%K 33.9%Cs 2.7%

TD 53.5±15.1R 30.3-70.6U 24.4%Th 38.3%K 34.2%Cs 3.1%

TD 81.0±30.9R 56.0-153.0U 24.6%Th 37.1%K 37.6%Cs 0.7%

TD 84.7±37.1R 34.0-149.2U 23.8%Th 39.5%K 36.6%Cs 0.1%

TD 98.3±42.7R 46.3-195.8U 22.9%Th 47.3%K 29.5%Cs 0.4%

TD 108.5±59.0R 15.4-208.8U 21.8%Th 50.2%K 27.0%Cs 1.0%

TD 61.2±15.8R 37.9-92.8U 32.7%Th 37.6%K 28.6%Cs 1.1%

TD 49.6±18.5R 10.5-71.8U 25.1%Th 37.0%K 41.5%Cs 1.6%

TD 66.1±14.3R 41.8-86.1U 31.8%Th 37.1%K 27.2%Cs 4.0%

TD 28.3±4.3R 23.9-34.2U 29.0%Th 27.9%K 33.8%Cs 9.4%

TD 62.6±18.9R 40.8-94.6U 31.2%Th 36.9%K 26.7%Cs 5.2%

TD 60.6±20.0R 22.9-81.3U 24.0%Th 36.0%K 37.6%Cs 2.3%

TD 88.0±47.3R 40.5-173.4U 20.3%Th 32.4%K 34.0%Cs 13.4%

TD 64.5±9.0R 52.4-74.1U 19.6%Th 37.0%K 19.4%Cs 24.0%

TD 48.0±17.0R 24.2-66.1U 24.8%Th 25.6%K 29.5%Cs 20.1% TD 30.6±13.3

R 10.1-48.3U 25.4%Th 27.5%K 36.7%Cs 10.4%

TD 22.3±7.3R 13.0-30.7U 32.9%Th 34.1%K 25.7%Cs 7.3%

TD 23.3±9.1R 15.2-39.2U 33.4%Th 27.7%K 29.3%Cs 9.7%

TD 29.8±7.0R 20.0-37.7U 20.8%Th 38.6%K 36.1%Cs 4.5%

TD 20.2±8.9R 11.2-31.3U 32.9%Th 36.5%K 36.1%Cs 1.8%

TD 23.7±4.9R 16.6-31.5U 37.4%Th 26.8%K 33.8%Cs 2.0%

TD 32.1±13.8R 12.9-48.6U 22.6%Th 33.8%K 33.4%Cs 10.2%

TD 42.0±19.7R 13.0-68.5U 23.3%Th 36.1%K 37.5%Cs 3.1%

TD 33.4±4.3R 29.7-39.5U 28.0%Th 35.4%K 33.5%Cs 3.1%

TD 59.2±6.7R 51.9-69.9U 48.5%Th 27.9%K 23.6%Cs 0.0%

TD 26.7±7.5R 17.5-35.9U 31.4%Th 31.8%K 29.3%Cs 7.4%

TD 36.3±13.2R 19.7-52.5U 27.4%Th 31.8%K 34.1%Cs 6.7%

TD 23.7±7.7R 14.1-39.8U 50.5%Th 21.9%K 25.5%Cs 2.1%

TD 37.9±19.8R 14.4-59.6U 27.3%Th 25.4%K 28.4%Cs 18.9%

TD 55.9±29.3R 27.4-107.4U 24.1%Th 31.1%K 41.3%Cs 3.5%

TD 37.5±8.1R 27.3-52.4U 25.3%Th 33.0%K 37.1%Cs 4.6%

TD 42.9±14.2R 22.9-69.1U 20.7%Th 37.3%K 40.1%Cs 1.9%

TD 46.2±16.1R 9.6-107.1U 22.1%Th 33.1%K 31.1%Cs 14.0%

TD 37.8±8.3R 28.8-48.9U 24.5%Th 34.1%K 35.7%Cs 5.7%

TD 46.2±7.0R 38.1-59.1U 23.4%Th 26.1%K 33.6%Cs 16.9%

TD 22.6±11.0R 10.6-37.1U 33.5%Th 29.9%K 34.5%Cs 2.1%

TD 40.7±22.0R 18.4-98.9U 38.5%Th 36.1%K 24.2%Cs 1.3%

TD 85.2±26.8R 44.5-113.7U 26.8%Th 43.0%K 29.0%Cs 1.1%

TD 29.9±4.9R 24.9-34.8U 27.6%Th 37.6%K 31.7%Cs 3.1%

TD 21.9±9.7R 6.6-39.7U 31.0%Th 33.1%K 31.9%Cs 4.0%

TD 34.7±14.1R 13.6-55.7U 29.2%Th 34.5%K 30.4%Cs 6.0%

TD 29.5±13.3R 6.7-57.8U 35.1%Th 25.6%K 34.4%Cs 5.0%

TD 30.3±9.3R 17.8-45.3U 33.0%Th 33.0%K 27.1%Cs 6.9%

TD 30.3±11.6R 15.6-44.0U 39.2%Th 33.4%K 23.3%Cs 4.1%

TD 22.4±3.8R 16.8-30.7U 50.6%Th 20.1%K 22.0%Cs 9.9%

TD 25.5±5.5R 18.5-33.4U 30.2%Th 34.1%K 33.5%Cs 2.1%

TD 33.8±12.7R 18.4-49.4U 48.4%Th 23.7%K 26.9%Cs 1.0%

TD 27.4±11.4R 13.3-46.5U 42.6%Th 28.9%K 25.9%Cs 2.6%

TD 35.1±0.8R 34.4-35.9U 54.4%Th 29.0%K 13.0%Cs 3.7%

TD 17.3±4.8R 9.5-21.6U 39.3%Th 34.6%K 26.1%Cs 0.0%

TD 42.5±9.6R 33.6-57.7U 40.1%Th 35.1%K 22.0%Cs 2.7%

TD 24.9±4.8R 20.1-29.7U 49.6%Th 28.1%K 18.7%Cs 3.6%

TD 34.7±12.0R 26.8-59.9U 55.3%Th 24.5%K 19.8%Cs 0.4%

TD 35.6±12.5R 16.7-65.3U 34.3%Th 34.4%K 30.1%Cs 1.2%

TD 22.4±7.9R 5.1-41.0U 44.7%Th 27.3%K 26.6%Cs 1.4%



s sa loni k i

N uc l e

a r T e c h

. L a b .

URANIUM SERIES THORIUM SERIES K-40 TOTAL

dwellings mean range mean range mean range mean range

nGy h-1 nGy h-1 nGy h-1 nGy h-1 nGy h-1 nGy h-1 nGy h-1 nGy h-1

26 15±4 9-26 21±5 12-34 22±4 14-31 58±12 40-87

60 13±3 9-22 20±3 12-31 23±4 14-35 56±9 41-80

225 15±4 5-28 21±5 6-36 23±5 5-35 59±13 18-99



s sa loni k i

N uc l e

a r T e c h

. L a b .



s sa loni k i

N uc l e

a r T e c h

. L a b .

0

20

40

60

80

100

120

140

0 5 10 15 20 25 30Ga m m a dos e ra te due to Ura nium s e rie s in nGy/h

Indoo

r rad

on co

ncen

tratio

n in B

q/m3

A p ar tm e n ts in g r o u n d an d fir s t f lo o r

0

10

20

30

40

50

60

70

80

90

1 00

0 2 4 6 8 10 12 1 4 16 18 20

G A M M A D O S E R A T E D U E T O U R A N IU M S ER IES (in n G y /h )

RADO

N CO

NCEN

TRAT

ION

(in B

q/m3)

A p ar tm e n ts ab o v e th ir d f lo o r



s sa loni k i

N uc l e

a r T e c h

. L a b .

Measurements in forest ecosystems



s sa loni k i

N uc l e

a r T e c h

. L a b .

TAXIARXISTAXIARXISOAKOAK

SANI SANI PINEPINE

From the combination of in situ gamma spectrometry measurementsFrom the combination of in situ gamma spectrometry measurements and Monte Carlo and Monte Carlo Simulations a conversion Factor C ( nGy/h per kBq./mSimulations a conversion Factor C ( nGy/h per kBq./m22 ) for Cs) for Cs--137 was deduced 137 was deduced

for the 2 forests.for the 2 forests.

C = 1 C = 1 C = 0.82C = 0.82



s sa loni k i

N uc l e

a r T e c h

. L a b .

Industrial application

Determining minimum alarm activities of Determining minimum alarm activities of radioactive sources in scrap metal using Gamma radioactive sources in scrap metal using Gamma

Spectrometry measurements and Monte Carlo Spectrometry measurements and Monte Carlo techniquestechniques



s sa loni k i

N uc l e

a r T e c h

. L a b .

Radioactive contamination of scrap metal

• Radioactive sources used in industry or medicine

• NORM radiation (naturally occurring radioactive material) from oil or chemical industries

• Contaminated metal from nuclear facilities



s sa loni k i

N uc l e

a r T e c h

. L a b .

Dealing with the problem• Installation of radiation portal monitors

– Metal recycling industries– Border crossing



s sa loni k i

N uc l e

a r T e c h

. L a b .

Comparison between measurements and simulations

Cs-137 point source

0.000

5.000

10.000

15.000

20.000

25.000

30.000

100 150 200 250 300 350 400 450 500 550 600Detector position x in cm

Unsc

attere

d pho

ton flu

x (ph

otons

per c

m2 an

d per

seco

nd)

experimental simulated (density 0.3 g/cm3) simulated (density 0.5 g/cm3) simulated (density 0.7 g /cm3)

detector position (x y = -30 cm z = 50 cm) Cs-137 source position ( x = 430 cm , y = 50 cm , z = 50 cm)



s sa loni k i

N uc l e

a r T e c h

. L a b .

• Homogenous load experiment• Scrap load experiments

– Old scrap E1– Shredded scrap

• Experiments’ simulation

440 cm390 cm

340 cm

135 cm

160 cm

780 cm

60 cm100 cm

Φ22 cm

40 cm

40 cm

240 cm

110 cm

108 cm

xz

xy

O

O



s sa loni k i

N uc l e

a r T e c h

. L a b .

Homogenous load experiment



s sa loni k i

N uc l e

a r T e c h

. L a b .

Minimum Alarm Activities Cs-137



s sa loni k i

N uc l e

a r T e c h

. L a b .

……Measurements abroad (Germany)

PTBPTB UDOUDO



s sa loni k i

N uc l e

a r T e c h

. L a b .



s sa loni k i

N uc l e

a r T e c h

. L a b .

Previous discharges of radioactivity from Mayak Production Previous discharges of radioactivity from Mayak Production Association plant in Urals, Russia have resulted in Association plant in Urals, Russia have resulted in

considerable radionuclide contamination of the Techa River, considerable radionuclide contamination of the Techa River, and consequent high radiation doses during the late 1940s and and consequent high radiation doses during the late 1940s and 1950s to residents of villages along the Techa River. The most 1950s to residents of villages along the Techa River. The most contaminated villages were evacuated in the period 1954 contaminated villages were evacuated in the period 1954 --

1962.1962.The aim of the SOUL project is to quantify risks of late health The aim of the SOUL project is to quantify risks of late health effects associated with loweffects associated with low--dose rate exposure to plutonium, dose rate exposure to plutonium, strontium and external gamma radiation. This will be done by strontium and external gamma radiation. This will be done by improving, updating and analysing dosimetric and health data improving, updating and analysing dosimetric and health data for the Mayak worker cohort (MWC), the extended Techa for the Mayak worker cohort (MWC), the extended Techa River cohort (ETRC) and the Techa River cohort (ETRC) and the Techa RRiver offspring cohort iver offspring cohort

(TROC).(TROC).



s sa loni k i

N uc l e

a r T e c h

. L a b .

• Dose conversion coefficients for film badges and tooth enamel for exposures at the early work places areevaluated ,by use of simulated photon spectra

• Due to differences in fuel parameters the exposure conditions at current work places differ from those of the early work places. However , measurements at current workplaces and the comparison with Monte Carlo simulated photon spectra at these workplaces are needed for validating calculations and simulation parameters.



s sa loni k i

N uc l e

a r T e c h

. L a b .

AUTH

PHOTON SPECTRA IN MAYAK WORK PLACES

• More than 400 spectra were measured in the course of work, 17 points of them with angle distribution (7 spectra in each point) All of them were “unfolded”using the codes and procedure developed by the AUTH scientists

• Due to specific regulations it was not possible for AUTH scientists to perform measurements inside MAYAK. However, it was possible to perform in common with the MAYAK scientists measurements in the MAYAK test ground



s sa loni k i

N uc l e

a r T e c h

. L a b .

AUTH

Photon spectra at the Radiochemical Plant: chem_3

0

1000

2000

3000

4000

5000

6000

20 120 220 320 420 520 620Energy (keV)

coun

ts

before stripafter strip

0

0.5

1

1.5

2

2.5

3

3.5

20 120 220 320 420 520 620Energy (keV)

Flux (

gamm

a per

cm2 s)



s sa loni k i

N uc l e

a r T e c h

. L a b .

AUTH

Validation :Comparison between measured and calculated photon flux energy distributions

• MAYAK PA work place• (No1, No2, No3): The

positions where the in situ gamma spectrometry measurements have been performed.

• 1: lead barrier. • 2: 257 mCi 137Cs source.



s sa loni k i

N uc l e

a r T e c h

. L a b .

AUTH

RESULTSUnscatteredFluxMeasured

UnscatteredFluxMCNP

No1 3.4 ± 0.5 3.9

No2 7.0 ± 1.0 7.7

No3 4.8 ± 0.7 4.2

Measured and calculated (MCNP)Measured and calculated (MCNP)unscattered photon flux unscattered photon flux

(photons per cm(photons per cm22 per second)per second)in the three locationsin the three locations

0.001

0.01

0.1

1

10

120 220 320 420 520 620Energy (keV)

Flux (

gamm

a cm-2

s-1)

simulatedmeasured

Experimental and simulated Experimental and simulated scattered photon flux energy distributionscattered photon flux energy distributionin position No2. A good agreement was in position No2. A good agreement was found also in the other two positions.found also in the other two positions.



s sa loni k i

N uc l e

a r T e c h

. L a b .

AUTH

0.001

0.01

0.1

1

10

120 220 320 420 520 620Energy (keV)

Flux (

gamm

a cm-2

s-1)

simulatedmeasured

POSITION No1POSITION No1

0.001

0.01

0.1

1

10

120 220 320 420 520 620Energy (keV)

Flux (

gamm

a cm-2

s-1)

simulatedmeasured

POSITION No3POSITION No3



s sa loni k i

N uc l e

a r T e c h

. L a b .

.. Exotic Use of Germanium detector

Measurement of cosmic radiation (muon dose rate) with a Germanium

detector



s sa loni k i

N uc l e

a r T e c h

. L a b .

5858

Typical spectrum of in situ gamma spectrometry

0500

100015002000250030003500400045005000

0 500 1000 1500 2000 2500Energy (keV)

coun

ts/216

00s

214214PbPb208208TlTl

212212PbPb 137137CsCs

214214BiBi228228AcAc

4040KK

208208TlTl



s sa loni k i

N uc l e

a r T e c h

. L a b .

5959

Typical spectrum of in situ gamma spectrometry

05

101520253035404550

2500 2550 2600 2650 2700Energy (keV)

coun

tsι/2

1600

s



s sa loni k i

N uc l e

a r T e c h

. L a b .

6060

Spectrum of in-situ γ-spectrometry with attenuation gain of preamp and amplifier

020406080100120140160180

0 20000 40000 60000 80000 100000 120000Enrergy (keV)

coun

ts /

1300

00 s

HPGe 20% efficiencyHPGe 20% efficiency



s sa loni k i

N uc l e

a r T e c h

. L a b .

Muon measurements with Germanium detectors

0

100

200

300

400

500

600

700

800

3-4

10-11

17-18

24-25

31-32

38-39

45-46

52-53

59-60

66-67

73-74

80-81

87-88

94-95

101-10

210

8-10

911

5-11

6

Energy (MeV)

coun

tsι /

200

00s

10%10% 20%20% 70%70%Shift of muon peak proportional to the crystalShift of muon peak proportional to the crystal’’s dimensionss dimensions



s sa loni k i

N uc l e

a r T e c h

. L a b .

6262

Spectra Simulated - Measured

HPGe 10% efficiencyHPGe 10% efficiency

HPGe HPGe 220% efficiency0% efficiency

HPGe HPGe 770% efficiency0% efficiency

RemarkRemark::The simulated spectra in the lower energies are

smaller then the measured ones

This is due to electron photon shower.



s sa loni k i

N uc l e

a r T e c h

. L a b .

6363

Dose calculation from a muon spectrum

00.10.20.30.40.50.60.70.8

3-4

12-13

21-22

30-31

39-40

48-49

57-58

66-67

75-76

84-85

93-94

102-10

311

1-11

2

Energy (MeV)

Abso

rbed

dose

rate

(nGy

/h)

ρ⋅⋅⋅=

VtEENED i

ii )()(&

wherewhere ::NN((EiEi)):: counts in energycounts in energy EiEi

tt: : measuring timemeasuring timeVV:: crystalcrystal’’s active volumes active volumeρρ: : crystalcrystal’’s densitys density

∑==

=

120

4)(

i

iiEDD &&Total doseTotal dose::

Conversion factorConversion factor C C = Dose= Dose(ICRU)(ICRU) / Dose/ Dose(Ge)(Ge) = 1.33= 1.33



s sa loni k i

N uc l e

a r T e c h

. L a b .

CORRESPONDING PUBLICATIONS• Clouvas et al Health Physics 74,216,(1998)• Clouvas et al Health Physics 76,36 (1999)• Clouvas et al Health Physics 78,295,(2000)• Clouvas et al Health Physics 79,274 (2000)• Clouvas et al Radiation Protection Dosimetry 94,233(2001)• Clouvas et al Health Physics 84,212 (2003)• Clouvas et al Radiation Protection Dosimetry 103,363(2003)• Clouvas et al Radiation Protection Dosimetry 112,267(2004)• Clouvas et al Health Physics 88,154 (2005)• Clouvas et al Radioactivity in the Environment , Vol7 , 1155, (2005)• Clouvas et al Radiation Protection Dosimetry 118,482,(2006)• Clouvas et al Radiation Protection Dosimetry 124,372,(2007)• Smetanin et al Radiation Protection Dosimetry 131,455,(2008)• Takoudis et al Nuclear Instruments and Methods in Physics Research A

599,74, (2009)• Takoudis et al Nuclear Instruments and Methods in Physics Research A

614,57, (2010)



s sa loni k i

N uc l e

a r T e c h

. L a b .

AUTH

The Team

Documents

IN SITU GAMMA SPECTROMETRY (1995-2010)...Nuclear Technology Laboratory A r i s t o t l e U n i. o f T h e s s a lo n i k i N u c l e a r T e c h. L a b . IN SITU GAMMA SPECTROMETRY