View
0
Download
0
Category
Preview:
Citation preview
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
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 .
CONTENTS
• Few words about our research group• some theory about in situ gamma
spectrometry• Presentation of the major results
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 .
ARISTOTLE UNIVERSITY OF THESSALONIKIARISTOTLE UNIVERSITY OF THESSALONIKI
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 .
ThessalonikiThessaloniki
Greek and Roman monumentsGreek and Roman monuments
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 .
ARISTOTLE UNIVERSITY OF THESSALONIKIARISTOTLE UNIVERSITY OF THESSALONIKI
ARISTOTLE UNIVERSITY OF THESSALONIKIARISTOTLE UNIVERSITY OF THESSALONIKI
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
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 .
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
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 .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
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 .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
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 .
CONTENTS
• Few words about our research group• some theory about in situ gamma
spectrometry • Presentation of the major results
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 .
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
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 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
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 .
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
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 .
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&
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 .
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
)
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 .
Simulation of the HPGe detectorManufacturer’s draft scheme HPGe as was simulated by Monte Carlo
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 .
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
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 .
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
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 .
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.
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 .
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
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 .
“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
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 .
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)
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 .
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
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 .
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
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 .
Simulation of 2π geometry
Simulation of 2π geometry (MCNP code). On the right, zoom in the detector’s area can be seen
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 .
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 ×= &&
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 .
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.
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 .
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)
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 .
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).
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 .
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 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.
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 .
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
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)
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 .
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
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 .
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
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 .
CONTENTS
• Few words about our research group• some theory about in situ gamma
spectrometry • Presentation of the major results
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 .
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%
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 .
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%
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 .
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
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 .
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 .
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
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 .
Measurements in forest ecosystems
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 .
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
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 .
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
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 .
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
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 .
Dealing with the problem• Installation of radiation portal monitors
– Metal recycling industries– Border crossing
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 .
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)
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 .
• 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
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 .
Homogenous load experiment
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 .
Minimum Alarm Activities Cs-137
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 .
……Measurements abroad (Germany)
PTBPTB UDOUDO
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 .
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 .
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).
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 .
• 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.
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 .
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
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 .
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)
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 .
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.
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 .
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.
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 .
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
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 .
.. Exotic Use of Germanium detector
Measurement of cosmic radiation (muon dose rate) with a Germanium
detector
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 .
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
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 .
5959
Typical spectrum of in situ gamma spectrometry
05
101520253035404550
2500 2550 2600 2650 2700Energy (keV)
coun
tsι/2
1600
s
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 .
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
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 .
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
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 .
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.
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 .
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
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 .
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)
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 .
AUTH
The Team
Recommended