Gamma Spectrometry at the Accredited Laboratory of STUK STUK - - PowerPoint PPT Presentation

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Gamma Spectrometry at the Accredited Laboratory of STUK STUK - - PowerPoint PPT Presentation

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Gamma Spectrometry at the Accredited Laboratory of STUK STUK Seppo Klemola Radionuclide Analytics y Research and Environmental Surveillance STUK - Radiation and Nuclear Safety Authority Fi l Finland d STUK STEILYTURVAKESKUS SkK

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SLIDE 1

Gamma Spectrometry at the Accredited Laboratory of STUK STUK

Seppo Klemola Radionuclide Analytics y Research and Environmental Surveillance STUK - Radiation and Nuclear Safety Authority Fi l d Finland

STUK • SÄTEILYTURVAKESKUS

STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY

1

SkK

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SLIDE 2

Contents

  • Accreditation
  • Gamma Laboratories
  • Spectrometers and measuring geometries
  • Spectrometers and measuring geometries
  • Software
  • Gamma-99

Gamma 99

  • UniSampo + Shaman
  • DECCA + VGSL
  • Database for gamma spectrometry
  • Applications
  • CTBT RNLab
  • CTBT RNLab
  • Metrology

STUK • SÄTEILYTURVAKESKUS

STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY

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SLIDE 3

Accreditation

  • Since 1999 the method of gamma spectrometric sample

measurements at STUK has been accredited according to the standard EN ISO/IEC 17025 by according to the standard EN ISO/IEC 17025 by

  • Accreditation renewed in 2003 and 2007
  • Two-grade scope of gammaspectrometric analysis in

g p g p y environmental samples, biological samples and foodstuffs

  • Gammaspectrometric measurements of Cs-137, Cs-134, I-131, K-

40 U- and Th-decay series 40, U and Th decay series

  • Advanced analysis, all radionuclides emitting gamma-rays in the

energy range of 30-2700 keV

Si th i ti f th D t t i 2007 ll

  • Since the reorganisation of the Department in 2007 all

measurements in Helsinki have been performed at the Radionuclide Analytics Laboratory (NAL)

STUK • SÄTEILYTURVAKESKUS

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SLIDE 4

G L b t Gamma Laboratory

Counting rooms: Counting rooms:

  • Special concrete and

mortar with low abundance of natural abundance of natural radionuclides

  • Controlled access
  • Special air ventilation to decrease background radiation due to 1) ambient

radon, 2) severe fallout

  • Monitoring of temperature and humidity

g p y

  • Separate counting and operator/computer rooms
  • Pipelines for liquid nitrogen supply

UPS t

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  • UPS + reserve power generator
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SLIDE 5

10 Spectrometers

  • coaxial HPGe

N1

nHPGe ORTEC pHPGe ORTEC pHPGe

Canberra

N2

pHPGe Ortec pHPGe

Canberra

B5 B4 G1

  • coaxial HPGe
  • vertical cryostat
HV- lähde

ORTEC 459

HV- lähde

ORTEC 659

HV- lähde

ORTEC 659 HV- lähde CAN- BERR A

  • 9 p-type, 1 n-type
  • rel eff 20-100%

lin.vahv. ORTEC 672 lin.vahv. ORTEC 572 lin.vahv. ORTEC 672 NIM BIN

lin.vahv. ORTEC 572

  • rel. eff. 20 100%
  • 12-14 cm Pb BG-shielding

Cu+Cd lined

Canberra 7023 Canberra 7023 NIM BIN NIM BIN

ORTEC DS j 2 0

ORTEC 919

ADC/MCB

Cu+Cd lined

  • DSP or NIM electronics, MCB

DSpec jr2.0

  • meas. control & analysis:

local PC or LAN workstations

GAMMA-2

HP-4000 LaserJet

STUK-verkko

DELL

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SLIDE 6

Standard measurement geometries

simple cylindrical:

  • P35: 0-30 ml, free sample height

P105 0 100

l

  • P105: 0-100 ml, free sample height

Marinelli:

  • 0 5 l fixed sample height

0.5 l, fixed sample height Measured on top of a detector end-cap New measuring geometries can be calibrated using semi- empirical DECCA-programme empirical DECCA programme

STUK • SÄTEILYTURVAKESKUS

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SLIDE 7

Software Software

  • Measurement control

MAESTRO f ORTEC d U iS

  • MAESTRO from ORTEC and UniSampo
  • Spectrum analysis
  • GAMMA-99 from STUK

GAMMA 99 from STUK

  • Windows-version 1997
  • cascade summing correction since 1983 ! (Andreev, 1981)
  • sample height and density corrections
  • sample height and density corrections
  • automatic and interactive operation modes
  • UniSampo + Shaman
  • Efficiency calibration calculation
  • DECCA
  • efficiency transfer method (Moens et al 1981)

efficiency transfer method (Moens et al, 1981)

  • developed in co-operation w. NRPA Norway in 1990
  • validated in ICRM and Euromet projects
  • VGSL Monte Carlo method from CTBTO

not validated

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  • VGSL Monte Carlo -method from CTBTO - not validated
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SLIDE 8

UniSampo

  • Member of the SAMPO family of

gamma-spectrum analysis programs

  • Run under Linux
  • The graphical user interface (X window can be redirected to another computer using

suitable software), interactive menu and cursor controls

  • Flexible batch language for automated spectrum analysis
  • Both linear and nonlinear peak fitting using precalibrated peak shapes
  • Optional step function under each peak of a multiplet
  • Automated energy and shape calibration features

gy p

  • Able to analyze 32K spectra with up to 2500 peaks, and 32 peaks in a single

multiplet extending over a fitting interval of 1024 channels

  • An interface to the expert system SHAMAN
  • Support for MCA hardware: measurement control
  • The first phase of the gamma-ray spectrum analysis: determination of the peak

positions, energies, areas, and intensities with the corresponding uncertainty estimates

STUK • SÄTEILYTURVAKESKUS

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SLIDE 9

Sh Shaman

  • Expert system for radionuclide identification of gamma-ray

t b B O Fi l d spectra by Baryon Oy, Finland

  • Rule-based expert system
  • mimics a human analyst: well-defined rules to discard false candidates and finds

the final solution iteratively

  • knowledge base consists of about 60 rules
  • Mathematical algorithms to qualitatively identify the radionuclides and to

determine:

lid ti iti d t ti t ki i t t TCS ti

  • nuclide activities and concentrations taking into account e.g. TCS corrections
  • MDA/MDC’s
  • associations between the nuclide’s gamma lines and spectrum peaks
  • Able to identify also most special peaks, incl. escape peaks, sum peaks, and

Able to identify also most special peaks, incl. escape peaks, sum peaks, and X-ray peaks

  • Utilizes a reference library with 3 648 radionuclides and 80 062 gamma lines
  • extracted from the ENSDF and NUDAT
  • In batch mode both input and output is file-oriented, enabling fully automated
  • peration: analysis pipeline
  • Options to store data to a database (Linssi)

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SLIDE 10

LINSSI LINSSI

  • SQL database for gamma-ray spectrometry:

SQL database for gamma ray spectrometry: LINux System for Spectral Information

  • Open source software (MySQL)

p ( y Q ) developed in collaboration with

  • STUK
  • Baryon Ltd

y

  • Helsinki University of Technology
  • Health Canada
  • Storing of all the relevant data starting from the

Storing of all the relevant data starting from the collection of (air) sample to the final analysis results

  • Enough information to enable a review of an analysis

g y

  • Emphasis on the analysis results and data directly

affecting the quality of the results

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SLIDE 11

LINSSI LINSSI

SS ( )

  • LINSSI 1.1 (2005)
  • 32 tables
  • 556 fields

556 fields

  • 2009: LINSSI 2.1
  • Freely available

y

  • Not dependent on UniSampo/Shaman
  • Data in structured text files
  • Complete description:

http://www.tkk.fi/Units/AES/projects/radphys/linssi/index.htm

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SLIDE 12

A l i P d ith D t b Analysis Procedure with Database

D

Sample collection

  • Optimisation of sample

flow

  • right sample (amount), right

D a

Sample collection and preparation Ap XML g ( ) g detector (type and efficiency), right counting time

  • Spectrum acquisition

t a Optimisation Spectrum acquisition

pplication L-format

  • Computer analysis
  • Evaluation of analysis,

reanalysis if needed a b Spectrum acquisition Spectrum analysis

n interfac ww

reanalysis if needed

  • All stages (to be)

integrated to LIMS with advanced handling of a s Spectrum analysis Evaluation

Reanalyses

ce, scripts ww-brow

advanced handling of uncertainties s e Reports

y

s wser

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SLIDE 13

Set-up & Procedures

LINSSI Database

U iS Sh

R ti

Acquisition

U iS Sh

Application interface, scripts XML-format www-browser

er er

Analysis 1

UniSampo Shaman

Reporting le data

Acquisition

Analysis n

UniSampo Shaman

spectromete spectromete

samp

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SLIDE 14

Applications / 1 Applications / 1

  • Surveillance of environmental radioactivity in Finland

y

  • Radioactive substances in air, deposition, surface water, drinking

water, milk, foodstuffs and in the Baltic Sea

  • Research, radioecological studies
  • Artificial radionuclides: fallout, NPP discharges, ...
  • Natural radionuclides: wood grain vegetables sediment
  • Natural radionuclides: wood, grain, vegetables, sediment, ...
  • Contracted services
  • Industry: NPP environmental monitoring swipe samples building

Industry: NPP environmental monitoring, swipe samples, building materials ...

  • Trade: radioactivity certificates e.g. for export of mushrooms ...
  • National and international organisations and institutes:

municipalities, universities, Geological Survey of Finland, IAEA Safeguards, CTBTO...

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g ,

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SLIDE 15

FIL07 CTBT di lid l b t FIL07 - CTBT radionuclide laboratory

CTBTO/IMS has 16 radionuclide laboratories of which 10 is certified certified STUK laboratory certified in 2003 Reanalysis of filter samples:

  • interesting (level 5)
  • interesting (level 5)
  • station QC
  • 1-7 days measurement
  • Low background long measurement time -> possibly

Low background, long measurement time > possibly hundreds of relevant peaks

Requirements

  • Performance better than the average station

g

  • Equipment
  • Formal certification from the CTBTO
  • Quality Assurance
  • Demanding internal QC program
  • Proficiency tests
  • Data integrity

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SLIDE 16

Applications / 2 Applications / 2

  • Support for radiation and nuclear safety authorities at

STUK

  • Dosimetry, metrology, inspections, NPP radiation safety,

safeguards, quality assurance safeguards, quality assurance

  • Emergency preparedness
  • Maintenance and development of equipment and competence

f id for rapid response

  • Development of analytical methods
  • Metrology of gamma emitting radionuclides
  • Metrology of gamma-emitting radionuclides
  • Maintenance of measurement standards for activity
  • accurate spectrometers with traceable calibration and validated

h d methods

  • traceable standard sources
  • Total volume: ~3 000 anal./year

STUK • SÄTEILYTURVAKESKUS

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y

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SLIDE 17

Metrology and measurement standards

  • Goal of the national metrological activities:

Radiation measurements in Finland are adequately accurate and internationally comparable

  • Task of the Laboratory: to maintain measurement standards to ensure the

reliability of activity measurements of gamma-emitting radionuclides

  • Standards are accurate spectrometers with traceable calibration, validated

methods, or certified radioactive sources

  • STUK is a member in a network for ionising radiation standard laboratories
  • Participates in the activities of ICRM (International Committee for

Participates in the activities of ICRM (International Committee for Radionuclide Metrology) and its Gamma-Ray Spectrometry Working Group

  • Intercomparison of methods for coincidence summing corrections in gamma-ray

spectrometry p y

  • Will formally apply for membership of ICRM

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SLIDE 18

(I C R M )

International Committee for Radionuclide Metrology (I.C.R.M.)

Gamma-Ray Spectrometry Working Group

  • Devoted to the development of the metrological aspects
  • f gamma-ray spectrometry and its applications
  • measurement techniques and equipment
  • determination of photon emission intensities
  • detector efficiency calibrations (including Monte Carlo methods)

detector efficiency calibrations (including Monte Carlo methods)

  • coincidence-summing corrections
  • uncertainties and correlations

new instrumentation

  • new instrumentation
  • X-ray spectrometry
  • 2006-07: Monte Carlo codes intercomparison exercise

p

  • 2008-09: Coincidence summing correction exercise

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