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Measuring isotopes accurately for a safer, healthier and sustainable - - PowerPoint PPT Presentation

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Measuring isotopes accurately for a safer, healthier and sustainable world Manfred Grning IAEA Environment Laboratories IAEA International Atomic Energy Agency Acknowledgment Thanks to my colleagues at IAEA, especially to: Sergey Assonov

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International Atomic Energy Agency

Measuring isotopes accurately for a safer, healthier and sustainable world

Manfred Gröning

IAEA Environment Laboratories

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Acknowledgment

Thanks to my colleagues at IAEA, especially to: Sergey Assonov Monika Horsky Sandor Tarjan Joanna Izewska Debbie van der Merwe Ahmed Meghzifene and to our colleagues at BIPM: Robert Wielgosz Joële Viallon Philippe Moussay Steven Judge

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International Atomic Energy Agency

Technical Agency associated to the UN System Atoms for Peace and Development

“The Agency shall seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world.”

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Overview

Long term cooperation with BIPM:

  • 1. Dosimetry and MRA
  • 2. MoU between IAEA and BIPM
  • 3. Trace Element Analysis and Nuclear Data
  • 4. Stable Isotope Ratios and Radionuclides
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  • 1. Dosimetry and the Mutual Recognition

Agreement

Secondary Standard Dosimetry Laboratories:

Provision of calibration for dosimetry equipment. Dosimeters are used to determine dose level for patients, staff or the public – importance that measurement results are consistent with SI system (radiation measurements)

  • Formal agreement to establish a Network of SSDLs

signed by IAEA & WHO (1976)

  • Since 1987, activities of the network are assessed by an

independent SSDL Scientific Committee (includes BIPM)

  • MRA signed in 1999
  • Currently 26 CMCs

86 SSDLs in 71 countries

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How is the audit carried out?

Small dosimeters are sent to radiotherapy centres for irradiation to verify the beam

  • utput used for patients’ treatments.

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Dose audit services 1969–2018:

  • 49 years of the IAEA/WHO postal dose audits
  • >13000 beam checks
  • ~2300 radiotherapy centres in 136 Member States
  • BIPM has provided reference irradiations for the

IAEA/WHO dose audits for >20 years

IAEA/WHO dose audits for radiotherapy centres

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1996-2017: N = 404 , m = 1.001, SD = 0.008

Reference irradiations for dose audits

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  • 2. Memorandum of Understanding

MOU formally signed in 2012, defines the main areas

  • f cooperation:
  • Mutual exchange of data and information in the

area of metrology of ionizing radiation and chemical measurements

  • IAEA representation in CCRI (full member 2011)
  • IAEA participation - as a signatory - in activities

related to CIPM MRA

  • BIPM participation in the SSDL Scientific

Committee

  • BIPM support to the IAEA/WHO dosimetry audits

and IAEA calibration services through reference irradiations and calibration of IAEA reference standards

  • Collaboration for measurement standards and

reference materials

  • Publication and dissemination of nuclear data
  • Participation in scientific events (e.g. IAEA

conferences), education and training, etc.

The IAEA Dosimetry Laboratory Cs-137 irradiator will be made available to BIPM staff for calibration purposes as of 2019

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  • 3. Trace Element Analysis & Nuclear Data
  • CCQM Key Comparison K75 (and

Pilot Study P118) “Determination of toxic metals in algae” – Platinum and Nickel , 2010 Shakhashiro et al.

  • Nuclear data – decay data evaluations with BIPM
  • Attendance at CCRI – Neutron standard cross sections
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  • 4. Stable Isotope Ratios, and Radionuclides
  • 100 Reference Materials available at IAEA
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Oxygen H2O

16O

Stable Isotopes: - e.g. oxygen in water

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16O

+

8 Protons 8 Neutrons

16O

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18O

+

8 Protons 10 Neutrons

18O

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18O 16O ~ 1 500

Oxygen: (18O/16O) = (2005.2±0.45)·10-6 Hydrogen: (2H/1H) = (155.76±0.05)·10-6

Ratio of 18O to 16O

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Hydrogen:

18O 16O

532 484 499 1 1 1

Oxygen:

13C 12C

104 87 89 1 1 1

Carbon:

from Coplen et al. 2002 2H 1H

12820 5714 6420 1 1 1

Range of Stable Isotopes in Nature

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Chemical analysis: Why to measure Stable Isotopes in Nature Stable isotopes ?

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Chemical analysis: Why to measure Stable Isotopes in Nature Stable isotopes ?

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“Stable Isotopes are the Colors for the Elements”

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Global Network Isotopes in Precipitation

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“Standards” required for any lab operation

Mass: Kilogram Length: Meter Kilogram – new definition, still requiring measurements Isotopes: Reference materials

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Raw water for VSMOW2 production

  • 4
  • 2

2 4 6 8

  • 1.2
  • 1.0
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 δ18O vs. VSMOW [‰] δ2H vs. VSMOW [‰] IAEA GSF USGS UEA CIO VSMOW2

  • 500
  • 400
  • 300
  • 200
  • 100
  • 60
  • 40
  • 20

δ2H (‰) δ18O (‰)

VSMOW2 –Vienna Standard Mean Ocean Water 2

VSMOW2 and VSMOW

  • 1
  • 0.5

0.5 1

  • 0.1

0.1 δ18O vs. VSMOW [‰] δ2H vs. VSMOW [‰] VSMOW VSMOW2

routine lab uncertainty

combined uncert.(+bias)

calibration data uncertainty

0 ± 0.02 ‰ Its isotopic composition is used for the triple point of water  Kelvin

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IAEA-603 Marble - Carbon isotope standard

Combined standard uncert. u(δ13C)= ±0.01‰ (homog. & calibration versus NBS19)  nearly ideal material for δ13C VPDB scale realization

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New Instruments requiring novel standards for CO2 Isotope Analysis

I0(n) I0(n)e(-a(n)L) L ~ 99% of 12C16O16O ~ 1% of 13C16O16O

636 is 13C16O16O 626 is 12C16O16O 628 is 12C18O16O

𝑺𝟐𝟒 = 𝒚𝟕𝟒𝟕 𝒚𝟕𝟑𝟕 𝑺𝟐𝟗 = 𝒚𝟕𝟑𝟗 𝒚𝟕𝟑𝟕 Commercially available ‘Optical’ instruments

  • Measure infrared absorption of individual isotopologues
  • Measure directly at concentration range of interest
  • Absorption can be modelled
  • Flow rates 0.1 to1 L/min

(Slide courtesy BIPM)

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25 www.bipm.org

Spread in isotope ratios of CO2 Standards in CCQM-K120, coordinated by BIPM

(Slide courtesy BIPM)

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Calibration Strategies for Optical Instrument Isotope Ratio Measurements developed by BIPM

δ13C1 δ13C2 x (CO2, A) x (CO2, B)

  • 1. Calibration in ‘delta scale space’ and correction for mole fraction effects

x (626, A) x (636, A) x (626, B) x (636, B)

  • 2. Calibration of mole fractions and conversion to delta scale

(Slide courtesy BIPM)

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27 www.bipm.org

BIPM Stable Isotope Reference Mixture Generator Facility

Lower end d13C Higher end d13C Mix – target d13C Filling aliquots with known pure CO2

(Slide courtesy BIPM)

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28 www.bipm.org

CO2 isotope ratio comparison (2020) (BIPM and IAEA Coordinators)

δ13C (VPDB) δ18O (VPDB)

Fossil Fuels Atmospheric CO2 Natural Gas Well Blended with enriched 13CO2

Comparison samples produced at BIPM Stability and homogeneity measured at BIPM ((1σ) δ13C = 0.04 ‰ (1σ) δ18O = 0.1 ‰ ) Reference Value assigned at IAEA ((1σ) δ13C = 0.01 ‰ (1σ) δ18O = 0.02‰

(Slide courtesy BIPM)

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IAEA Carbonate - CO2 isotope analysis system

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Aliquoting CO2 from BIPM vessels

Dosing valves BIPM vessels (~2 bar) CO2 reference gases at IAEA-lab

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Tests at IAEA on BIPM mixed CO2-vessels (last week) – Successful Performance check

  • 14.700
  • 14.650
  • 14.600
  • 14.550
  • 14.500
  • 14.450
  • 3.600
  • 3.550
  • 3.500
  • 3.450
  • 3.400
  • 3.350

d18O, ‰ VPDB-CO2 d13C, ‰ VPDB

Aliquots Average

d13C=-3.508 ±0.006 ‰ (n=10) d18O=-14.560 ±0.029 ‰ (n=10)

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CO2 concentration in the atmosphere

SRIPPS; NOAA

IPCC – Report:

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Carbon Cycle

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Carbon Cycle - reference materials

Annual change in mean δ13C: ~0.02‰ Precision required for any laboratory: ±0.02‰ for 40 years!!! Ultra-stable reference material  IAEA-603 ±0.01‰

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Carbon Isotopes

0.02‰ ≈ 1 Gt C Ultra-stable reference material  IAEA-603 ±0.01‰

  • 1.5
  • 1.0
  • 0.5

0.0 0.5 1.0 1.5

  • 0.04
  • 0.03
  • 0.02
  • 0.01

0.01 0.02 0.03 0.04

Carbon Flux (GtC/ y r) Uncertainty in d13C (‰ )

CO2 partition between Land and Ocean Total f lux to Land and Ocean~4.5 GtC

Positive Bias Negative Bias More Share for Land More Share for Ocean

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Carbon Cycle – BIPM and IAEA

  • New laser instruments – require new standardisation
  • BIPM developed a CO2 calibration strategy
  • Measurement precision is achieved for CO2
  • Initiative for Comparison of CO2 isotope ratios in 2020
  • IAEA CO2 / CO2-in-air isotope ratio reference materials
  • CCQM Isotope Ratio Working Group established
  •  Excellent cooperation for benefit of environmental

monitoring worldwide

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Habitats / endangered species

Timber from concessions versus illegal sources – validation of origin Ivory origin CITES Work on Reference materials & on Sampling Guidelines

IvoryID webpage

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Radionuclides: ALMERA Network

  • Analytical Laboratories for the Measurement of Environmental

Radioactivity: Network of 177 laboratories in 89 countries Proficiency Tests Validated Analytical Procedures

ALMERA Network Core Activities

Forum for Sharing Knowledge Training Courses and Workshops

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Radionuclides: Support for Member State laboratories

Proficiency tests for 400 laboratories annually Cooperation with CCRI ?

Bq/kg

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Th Than anks ks fo for y r your ur at atte tent ntio ion

E-Mail: m.groening@iaea.org