In-situ radionuclide quantitative characterization in aquatic ecosystems

using the KATERINA detector

C. C. TsabarisTsabaris, D.L. , D.L. PatirisPatiris, G. , G. EleftheriouEleftheriou, M. , M. KokkorisKokkoris, R. , R. VlastouVlastou

Hellenic Centre for Marine Research, Institute of Oceanography, Hellenic Centre for Marine Research, Institute of Oceanography, Attica, Attica, GreeceGreece

National Technical University of Athens, Faculty of Applied MathNational Technical University of Athens, Faculty of Applied Mathematics ematics and Physics, Athens, Greeceand Physics, Athens, Greece

Collaboration

Developed and constructedDeveloped and constructed at at Hellenic Centre for Marine Research (HCMR)Hellenic Centre for Marine Research (HCMR)

CalibrationsCalibrations performed at performed at National Technical University of Athens (NTUA)National Technical University of Athens (NTUA)

SimulationsSimulations performed in collaboration with performed in collaboration with NTUANTUA

Outline

��Status of measuring techniques for marine Status of measuring techniques for marine radioactivityradioactivity��The KATERINA systemThe KATERINA system��Laboratory facilities Laboratory facilities –– calibrationscalibrations��Monte Carlo Simulations (GEANT4 code)Monte Carlo Simulations (GEANT4 code)��Real Time operation (POSEIDON network)Real Time operation (POSEIDON network)��Field measurementsField measurements��ComparisonComparison��Future PlansFuture Plans

Status of Measuring Techniques��Lab based TechniqueLab based TechniqueTraditional Sampling and Laboratory Analysis by using Traditional Sampling and Laboratory Analysis by using HpGeHpGedetectors.detectors.The method is applied at HCMR for NORM and The method is applied at HCMR for NORM and 137137Cs analysis.Cs analysis.��InIn--Situ Monitoring Technique (option to RealSitu Monitoring Technique (option to Real--Time) Time) Detectors:Detectors: HPGeHPGe inin--situ (high consumption) and NaI(~1situ (high consumption) and NaI(~1--2W)2W)

Radioprotection and Oceanographic applications (Geophysical and Meteorological)

Advantages in radioprotection:Advantages in radioprotection:1) Screening of Contaminated areas concerning facilities which p1) Screening of Contaminated areas concerning facilities which pollute the marine ollute the marine environment environment 2) Mapping of large areas to estimate levels and distribution of2) Mapping of large areas to estimate levels and distribution of N/A radionuclides N/A radionuclides 3) Information on the nature of radioactive substances contained3) Information on the nature of radioactive substances contained in underwater in underwater objectsobjects4) Continuous monitoring and Real4) Continuous monitoring and Real--Time data transmission provides early warning Time data transmission provides early warning In situ Applications:In situ Applications:Radon daughters measurements on Submarine Groundwater DischargeRadon daughters measurements on Submarine Groundwater DischargeRadon daughters measurements near fault region Radon daughters measurements near fault region Radon daughters variations on rainfallRadon daughters variations on rainfallSeabed mappingSeabed mapping

40K and 137Cs decay schemes

�� They belong to the first group at the periodic tableThey belong to the first group at the periodic table�� They are They are monoenergeticmonoenergetic gamma emittersgamma emitters

The underwater spectrometer KATERINA patented INT.CL: G01T 7/00

Specifications•Crystal: 3x3” NaI•Consumption ~ 1.2 W (100mA)•Resolution at 662keV: <6%•Variable Εnergy Range•Adjustable spectroscopy: max of 2048 channels•Operating Temperature: 0-500C.•Correction for voltage drifts.•Adjustable HV voltage•Adjustable amplifier gain, PZC and shaping time.•Autonomy (without PC connect)•Option for Real Time (software independent)

Hardware��Analog Nuclear Electronics Analog Nuclear Electronics (Pre(Pre--amplifier, Shaping amplifier, Shaping Amplifier + Gain + Base Line Amplifier + Gain + Base Line Restoration + Pole Zero Restoration + Pole Zero Cancellation + shaping time).Cancellation + shaping time).��Digital Electronics Digital Electronics (Multichannel Analyzer + (Multichannel Analyzer + successive approximation ADC successive approximation ADC + RS232 and USB Interface).+ RS232 and USB Interface).

Experimental set up (lab)

��Point sources Point sources calibration (15cm calibration (15cm and 25 cm)and 25 cm)��Without housing Without housing (first figure)(first figure)��With housing With housing (second figure)(second figure)

Comparison for 137Cs (with and without the housing)

��Similar energy Similar energy resolutionresolution��Similar Compton tailSimilar Compton tail��variation of the total variation of the total efficiencyefficiency��Peak to total ratio Peak to total ratio variationvariation

energy (keV)0 200 400 600 800 1000 1200

coun

ts

0

1000

2000

3000Cs-137 without acetalCs-137 with acetal

Marine Calibration Sources

Gamma ray sourcesGamma ray sources Half LifeHalf Life-- 4040K (1461keV) K (1461keV) 1.3x101.3x1099 yearsyears-- 137137Cs (661keV) Cs (661keV) 30.17 years30.17 years-- 99m99mTc (141 Tc (141 keVkeV)) 6 hours6 hours-- 111111In (162, 246 In (162, 246 keVkeV)) 67.9 hours67.9 hours

Laboratory facility at NTUA

�� Tank with volume of 5.5mTank with volume of 5.5m33�� Pump for circulation of the Pump for circulation of the waterwater�� Hardware and software for Hardware and software for the acquisitionthe acquisition�� The SPECTRG software The SPECTRG software package for the analysis of package for the analysis of the measured data (NCSR the measured data (NCSR ““DemokritosDemokritos””))

Calibration spectra

Energy (keV)0 500 1000 1500 2000 2500 3000

Coun

ts

101

102

103

104

105

Cs-137 K-40 with backgroundCs-137 K-40 without background

Continued (99mTc)

Ånergy (keV)0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

coun

ts

100

101

102

103

104

105

106

107

0 50 100 150 20010x100

13x100

16x100

18x100

21x100

23x100

26x100

28x100

31x100

33x100

Resolution calibration

Energy (keV)0 500 1000 1500 2000 2500 3000

FWHM

2 (ke

V)2

0

2000

4000

6000

8000

10000

12000

14000

Measurementsf2= -669.48+4.55*E

Comparison with DUS system

Energy (keV)0 400 800 1200 1600 2000 2400 2800

Coun

ts

1e+1

1e+2

1e+3

1e+4

1e+5

137Cs and 40K from D.U.S137Cs and 40K from K-A-TE-RINA

Comparison with RADAM system (99mTc)

Energy (keV)0 100 200 300 400 500

Coun

ts

0

1e+6

2e+6

Tc-99m from RADAMTc-99m from K-A-TE-RINA

Intercalibration exercises (in-situ and lab)

BiBi--214214

PbPb--214214

PbPb--210210

0.010±0.0010.10±0.022.0+0.21.9±0.2lab

0.012±0.0030.12±0.011.9±0.11.7±0.2in-situ

137Cs(Bq/l)

208Tl(Bq/l)

214Bi(Bq/l)

214Pb(Bq/l)

Broad Energy Germanium Detector

Monte Carlo Simulation using GEANT4

Taking into account the typical Taking into account the typical interactions in the water, in the interactions in the water, in the material of the housing and in material of the housing and in the the NaINaI crystal.crystal.

InteractionsInteractions�� Compton scatteringCompton scattering�� Photoelectric Photoelectric �� Pair productionPair production

c/s

Eγ

γ

Water

ΝaI

γe-

Effective volume of gamma rays in water

Simulated values of VeffPhotopeak counts versus volume, input: 2,000,000 gammas/m3

Simulated 40K spectrum40K

Measuring Time: 3 days

E[channels]0 100 200 300 400 500

gamm

as/m3

101

102

103

104

105

measured datasimulation A (no scattering in the POM housing)simulation B (taking into account the scattering in the POM housing)

Simulated spectrum of 111In

Ånergy (keV)0 100 200 300 400 500 600

coun

ts

10x100

100x100

1x103

10x103

100x103

simulationexperiment

Efficiency simulation with GEANT4

VNN

Vtotalphotopeak

effphm /== εε

1) Running the code with constant number of gammas/m3 (~2,000,000 gammas/m3)2) Volume values are above the Veff

Simulated Marine efficiencypublished in Env. Mon. & Assessment

Ånergy (keV)0 500 1000 1500 2000

å*V (m3 )

0,00010

0,00012

0,00014

0,00016

0,00018

0,00020

0,00022

0,00024

0,00026

0,00028

marine efficiencyfitting

Minimum Detectable Activitypublished in Env. Mon. & Assessment

Energy (keV)0 500 1000 1500 2000 2500 3000

MDA

*I ã (B

q/m3 )

10

20

30

40

50

60

70

80

Natural and anthropogenic R/N in Butrintlagoon, Albania

Seabed sediment characterization

Vivari Cannel

Burtint Lake

Pavllo River

-3

2

7

12

17

22

27

Sand

Muddy Sand

Mud

3− + + − −Ra Th Cs ΚF = 0,048A 0,24A 0,65A 0,0020A ,6

Thermaikos Gulf (North Greece)

Thermaikos Gulf (surficial 137Cs variation)

POSEIDON Network

�� HeightHeight: 7.9 : 7.9 m m �� WidthWidth:: 1.75 1.75 mm�� WeightWeight: : 900900 kkgrgr�� EnergyEnergy: : Solar Solar

panels + batteries panels + batteries �� CommunicationCommunication: :

Imarsat C, GSMImarsat C, GSMevery 3 hoursevery 3 hours

Study area

Field measurements (Aquatic measurements) published in Applied Radiation and Isotopes

Eã[keV]0 500 1000 1500 2000

cps

10-4

10-3

10-2

10-1

100

214 B

i & 208 T

l & 137 C

s

40K

214 B

i

214 P

b

C h a n n e ls0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0

coun

ts

1 0 0

1 0 1

1 0 2

1 0 3

1 0 4

1 0 5

2 2 2 R n r e s u l t s : m e a s u r e d a c t i v i t y : 1 4 5 0 B q / m 3

a c t i v i t y a t o p e n s e a : 3 - 5 B q / m 3 3

2 1 4 B i( d a u g h t e r o f 2 2 2 R n )

4 0Κ

2 1 4 B i( d a u g h t e r o f 2 2 2 R n )

Application in Monaco: Groundwater fluxes on Submarine discharges

y = -0.5102x + 21.236R2 = 0.3675

0123456789

10

20 25 30 35 40Salinity

222 Rn

ex [B

q/l]

Flow rate: 6 m3/min

Third Deployment using an ROV in Stoupapublished in Sea Technology

Minimum flow rate: 16m3/min

Results (Stoupa experiment)

System Improvements

Software for automated analysis of the acquired gamma ray spectrSoftware for automated analysis of the acquired gamma ray spectraaInstalling the system in a network of floating measuring systemsInstalling the system in a network of floating measuring systems and and

platformsplatformsUpgrade for depths up 6000mUpgrade for depths up 6000m

Marine system for geophysical and Marine system for geophysical and radioprotectionradioprotection purposespurposes

((WarningWarning/ / AlarmAlarm))

Future Plans �� GEANT4 and MCNP5 simulations on sediment spectra for GEANT4 and MCNP5 simulations on sediment spectra for

efficiency estimation.efficiency estimation.�� Include special hardware for userInclude special hardware for user--independent automatic independent automatic

gamma ray spectra analysis in order to inform directly the gamma ray spectra analysis in order to inform directly the responsible operational centreresponsible operational centre�� Applying the system as a dosimeter in the water as well as in Applying the system as a dosimeter in the water as well as in

the sediment for NORM and the sediment for NORM and 137137Cs.Cs.�� Applying the system in a network for monitoring radon on Applying the system in a network for monitoring radon on

submarine faults (ESONET project in Marmara Sea)submarine faults (ESONET project in Marmara Sea)�� Seabed characterization at specific NORM sites with Seabed characterization at specific NORM sites with

increased activity concentration (like fertilizer industry) increased activity concentration (like fertilizer industry) (test in Cyprus)(test in Cyprus)�� RealReal--Time Monitoring radioactivity in terrestrial Time Monitoring radioactivity in terrestrial

environment as well as in airenvironment as well as in air--sea interaction sea interaction environment environment

Test deployment in Stoupa(South Peloponnesus)