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Neutron Activation Analysis at the Radiochemical Laboratory, Institute of Nuclear Techniques, Budapest University of Technology and Economics N. Vajda, Zs. Molnár, M. Balla, D. Bódizs, IWIRad Bucharest, 20-21 June 2005
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Contents Facility INAA –accredited procedure uncertainty budget method validation Application examples: geological samples archaeological samples biological samples RNAA analysis of 129 I
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Equipment for the measurement of trace elements by NAA γ spectrometer training reactor pneumatic transport Ф th = 2E12 /s/cm 2 system
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Radiochemical laboratories for „high” activity samples for low activity samples hot cell facility for processing irradiated samples
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Training reactor vertical irradiation channels with several thermal irradiation positions rabbit system with 2 irradiation positions φth: 2.6E12/cm2/s (100 kW, thermal channel) φth/φepi: 26-33 (100 kW, thermal channel) HPGe detectors and MCAs efficiency:resolution: well type Ge14 %1.95 keV POP-TOP Ge22 %2.5 keV MCA: S100 (16k), Accuspec B (8k) SAMPO 90, Gennie 2000 NAA in numbers
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INAA Comparator technique: Au comparator Zr flux monitor Standard conditions:sample preparation irradiation measurement standardization
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Sample preparation : weighing :sample, gold, Zr humidity, impurities of vials Irradiation: Measurement : Standardisation flux variation, th e, irr. time counting statistics, geometry, dead time, timing, background c analyte Uncertainty budget / major sources of uncertainty: counting statistics: 0.2-30 %;k factors: 2-7 %
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Uncertainties of k factors
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QC Analysis of SRMs FA fly ash, S7 soil-7 MS marine sediment
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QC Analysis of SRMs
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Ce
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Method validation: inter- comparison exercise
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Method validation: inter- comparison exercise
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ElementAverage σ (k=2) Mn %1,88 +-0,1 Cu %1,08+-0,2 V ppm704 +-50 Cr %25,6+-1 Sb ppm5,2+-0,3 As ppm25,8 +-2 Fe %37,5 +-1,5 Co ppm398 +-20 Ni %29,4 +-2 W ppm69 +-3 Mo %3,24 +-0,5 Analysis of steel BSS3 (intercomparison)
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APPLICATION EXAMPLE: INAA Analysis of archaeological samples Fingerprinting of archaeological ceramic materials: Multivariate statistical methods using trace element data for provenance studies of ceramics. Terra sigillata ceramics used in Aquincum were not locally manufactured.
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Jan Gunneweg, MartaBalla Jan Gunneweg, Marta Balla The Provenance of Qumran Pottery by Instrumental Neutron Activation Analysis COST G8 Qumran Meeting 21-23 May 2005
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Main goals to trace pottery by its chemistry to their place(s) of manufacture to establish the relation between pottery found in the settlement and the caves to study what pottery was locally made and which was brought in from elsewhere to learn the interregional contact between Qumran and its surroundings COST G8 Qumran Meeting 21-23 May 2005
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Sample selection 1.Qumran reference samples 2.Clay and ceramic samples from Jericho, Jerusalem, Hebron, Callirhoe, ‘Ain Feshkha 3.166 pottery samples from the settlement and the caves COST G8 Qumran Meeting 21-23 May 2005
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Analytical results evaluated by multivariate statistics COST G8 Qumran Meeting 21-23 May 2005
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Most important results and archaeological conclusions Qumran’s local chemical fingerprint has been defined 5 chemically different groups of pottery were determined and their probable provenance have been localized Analysis of clay and ceramic samples from other sites of the Dead Sea region provided reference data for workshop assignment Pottery serves as a connecting link between the settlement and the caves COST G8 Qumran Meeting 21-23 May 2005
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APPLICATION EXAMPLE: INAA Analysis of geological samples mineral separates, bulk rock lanthanides and other incompatible trace elements Typical detection limits: Processes of igneous petrogenesis, paleotectonic and paleogeographic position of rocks
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APPLICATION EXAMPLE: INAA Analysis of biological samples brain biopsy samples to study Alzheimer desease alkali metals + iodine Uncertainties LD INAAICPMSICPAESINAAICPMS ICPAES unc%STD%unc%STD%unc%STD% Li(ng/g) --33252831 Na(ug/g) 1258402 K(ug/g) 5326130090 Rb(ug/g) 542110,60,02 Cs(ng/g) 105524720 I(ng/g)7 Good reproducibility in INAA !
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RNAA for the analysis of radionuclides Methods: α spectrometry β spectrometry γ spectrometry RNAA Long-lived „difficult to determine nuclides„ (DDN) in the nuclear fuel cycle e.g. 129 I T 1/2 =1.57E7 y 129 I(n,γ) 130 IT 1/2 =12.4 h 99 Tc T 1/2 =2.13E5 y 99 Tc(n,γ) 100 TcT 1/2 =15.8 s Too short!
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Radiochemical separation procedure for the simultaneous separation of DDNs 129 I 99 Tc Pu-Np-U Ni SrAm-Cm
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APPLICATION EXAMPLE: RNAA 129 I analysis: - Ground level measurements in well water on the site of the future radioactive waste disposal area: analysis of 100 L of water <μBq/L - Analysis of nuclear wastes: evaporation concentrates: 10-100 mBq/L spent ion exchange resins: 1-10 Bq/L
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γ spectrometry Determination of Gamma Emitting Fission and Corrosion Nuclides in NPP Primary Coolant by Gamma Spectrometry Determination of Activity Concentration of Nuclear Power Waste by Gamma-Spectrometry Determination of Activity Concentration of Environmental Samples by Gamma-Spectrometry NAA NAA of geological and environmental samples NAA of archaeological potteries α and β spectrometries Analysis of Uranium, Plutonium, Americium, Curium, Nickel and Strontium Nuclides in Radioactive Wastes Determination of Strontium and Plutonium Isotopes in Concentrates of Water Samples Accredited procedures:
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Staff: N. Vajda, Zs. Molnár, M. Balla, D. Bódizs, Gy. Csuday, J. Szabó, K. Jovicza PhD students: A. Kerkápoly, Sz. Osváth, É. Kabai, D. Tar, G. Surányi
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