Transcript Main Research Area and International Activities of the

Main Research Area and International
Activities of the Radionuclide Metrology
Laboratory from IFIN-HH
Maria Sahagia
“Horia Hulubei” National Institute of Research and
Development for Physics and Nuclear Engineering,
IFIN-HH, Bucharest, Romania
Second workshop for radioactive Decay Data Evaluators,
DDEP 2008
Bucharest, Romania, May 12 – 14, 2008
Subjects to be treated
• General presentation of the Radionuclide
Metrology Laboratory (RML)
• Main research areas
• International cooperation of RML
History
•IFIN-HH was founded, under the name of
“Institute for Atomic Physics”, in 1949.
•Name IFIN was given in 1977, what became
IFIN-HH (Horia Hulubei) in 1996.
• Radionuclide
Metrology
Laboratory
(RML) was created in early sixties.
The founder is Dr. Enric Leon Grigorescu.
Official Status of the Laboratory
• Absolute (primary) standardization in the field.
• 2005-Protocol, National Metrology Institute (NMI) -Romanian
Bureau of Legal Metrology (BRML) and IFIN-HH:
- IFIN-HH - owner of the Primary Standard of Activity Unit
(Becquerel) and derived units
- BRML designated IFIN-HH: participant in International
Committee for Weights and Measures - Mutual Recognition
Arrangement (CIPM-MRA) ionizing radiations, CIPM-MRA, Annex
A.
- BRML appointed IFIN-HH: representative in the Technical
Committee for Ionizing Radiations (IR-TC) of EURAMET
(EUROMET)
• BRML authorizes RML for legal metrology activities and
attests it , as a calibration laboratory
Infrastructure and personnel
RML- part of the IFIN-HH Radioisotope Department (RD)
- Facilities for safe operation of sealed and open radioactive
sources: radiochemistry laboratory, a balance room, two
measurement laboratories, auxiliary rooms;
- Separation from the RD crossing activities. Climatic regime
and radiation background control-recently improved.
- As a part of IFIN-HH, RML has access to all the available
facilities, library, computing and communication network
•RML Staff: 5 permanent and 1 associate members
2 PhD, 1 PhD student, 1 Scientific researcher, 1 young physicists,
1 technician.
Thanks are due to Dr. E.L.Grigorescu, who retired.
Main research areas
• Methods and equipment for absolute
standardization
• Methods and equipment for spectrometry and
for relative standardization
• Methods and equipment for preparation of
radioactive sources
• Metrology services and assurance of
traceability
Absolute standardization:
• 4πPC-γ coincidence method
• Liquid Scintillation Counting
4πPC-γ coincidence method
Standardization of radionuclides emitting several coincident
radiations and of pure beta emitters, by the tracing method.
- First system, manually operated, constructed during sixties,
contains a home made Proportional Counter (PC) - flow type,
pure methane , and a NaI(Tl) detector.
-Electronics is NIM modular of types Nuclear Enterprises and
Canberra.
The method and equipment were verified in
international comparisons
X, gamma - X, gamma coincidence detection block two thin NaI(Tl) detectors - standardization of 125I,
M. Sahagia et al. Appl.Radiat.Isot.3986/2008, under print.
Main Romanian contribution
in the development
of the method
(i) Dead time and coincidence resolution time corrections,
E.L. Grigorescu, Mesucora Congress, Paris 1963;
(ii) Measurement of beta, electron capture-gamma emitters,
by the efficiency extrapolation:
E.L. Grigorescu, Nucl.Instrum.Meth. 112(1973)151 ;
E.L.Grigorescu, et al. Nucl. Instr.and Meth A369(1996) 414420 and subsequent papers;
(iii) Efficiency tracer for pure beta emitters and
extrapolation for emitters with transition to the ground
level. M.Sahagia, Marianske Lazne , Symp., 1979, Proc., 2/5,
pp.180-187, and followings;
(iv) Standardization of special radionuclides, 99mTc,
M.Sahagia, Appl.Radiat.Isot. 64(2006)1234-1237.
New coincidence system
• The Research project, supported - Romanian
National Authority for Scientific Research (ANCS),
2006-2008,
• New 4πPC-γ coincidence system: a Proportional
Counter, two NaI(Tl) detectors and new electronic
modules, ORTEC type or home - IFIN-HH made,
operated in a semi automatic regime - constructed, is
under testing :
C.Ivan et al. IFIN-HH Internal Rep. 2007.
• Thanks are due to the Bureau International des
Poids et Mesures (BIPM), ENEA (Italy) and
Laboratoire National “Henri Becquerel” (LNHB)
from CEA-Saclay, France, for their help in
designing the new system.
Liquid Scintillation Counting
•Liquid Scintillation Counter, principle of the Triple to
Double Coincidence Ratio (LSC-TDCR):
Detection block with three photomultipliers and associated
electronics
• Contribution of the LNHB-France and RC-Poland
LSC-TDCR method implemented, and the system used
for standardization of : H-3, C-14, P-32, Ni-63, Sr-89, Tl204, Am-241, Cs-137, Fe-55
•Method and system - verified by bilateral or key
comparisons.
A.C. Razdolescu and P. Cassette, Appl. Radiat. Isot. 60 (2004) 493497;
A.C. Razdolescu, et al, Appl. Radiat. Isot. 64 (2006) 1510-1514.
ANCS project – LSC improvements under way:
(i) New photomultipliers, type Burle 8850
(ii) A new detection block with 6 Channel
Photomultipliers (CPM)
(iii) A NaI(Tl) probe for the application of the
4πLS-γ coincidence method.
(iv) The LabVIEW operation software - under
installation.
Methods and equipment for spectrometry and
for relative standardization
• Spectrometric methods
• Equipment and methods for relative
(secondary) standardization
Spectrometric methods
- Traditional work: GeHP gamma-spectrometer of the RD
- Contribution in development of the spectrometry method:
(i) Use of the coincidence and Compton suppression
anticoincidence for the low level activity measurements.
E.L.Grigorescu, Nucl.Instrum.Meth. A 369 (1996) 574-577;
A. Luca et al., Appl. Radiat. Isot. 53 (2000) 221-224;
E.L. Grigorescu et al., Appl. Radiat.Isot. 61 (2004) 191-195;
(ii) Studies on the shape of the gamma-ray background under
the total absorption peaks,
A.Luca et al., Appl.Radiat.Isot. 60 (2004) 233-237;
(iii) Measurement of the X- and gamma-rays emission intensities
for Zn-65, Sb-124
M.M.Be, ICRM2005, Appl.Radiat.Isot. 64 (2006)1396;
Content of the system
Three detection blocks:
(i)Gamma-ray detector: coaxial HPGe type,
ORTEC model GEM-25P4, relative efficiency 30% (60Co);
resolution 0.62 keV for 122 keV and 1.67 keV at 1333 keV;
energy interval: 30 keV - 3 MeV. Shield: old lead, copper and
a 1 mm thick tin foil - under construction
(ii) X-ray detector - Si(Li), CANBERRA : energy interval 1
keV-50 keV, resolution 166 eV at 5.9 keV
(iii) Alpha spectrometry chamber - surface barrier
silicon detector, and vacuum system.
All the three detection blocks are compatible (or adapted) to
the analysis system, ORTEC, consisting from a digital
spectrometer, connected to a personal computer.
Software facilities :
ORTEC GammaVision-32 (Model A66-B32), version
6.01, Advanced Measurement Technology, Inc.
(AMETEK), USA;
ORTEC MAESTRO-32 (Model A65-B32), version 6.06,
Advanced Measurement Technology, Inc. (AMETEK),
USA;
GESPECOR, Romanian (Prof. O. Sima) - German (Dr.
D. Arnold) - calculation of coincidence summing
corrections and transfer of efficiency calibration between
various geometries and matrices.
Equipment and methods for relative
(secondary) standardization
Well-type ionization ionization chamber
CENTRONIC IG12/20A
Transfer instrument, for secondary standardization
of radioactive sources and solutions.
Calibration of the chamber.
Calibration figures were assigned for Various Gamma
emitters and various geometries
(i)High activity sealed sources: certified by other
producers - 241Am, 137Cs, 60Co.
(ii)Solutions vials: 2ml , PTB, Germany; 3.6 ml, BIPM SIR; 5 ml , for radiopharmaceuticals; response is
dependent of the volume of solution, mainly for low
energy gamma-rays emitters.
Calibration for solutions
•Calibration with solutions absolutely standardized in RML by
4πPC-γ coincidence method , for 17 radionuclides: 54Mn, 57Co, 65Zn,
99mTc, 124Sb, 131I, 133Ba, 134Cs, 137Cs, 152Eu, 153Sm, 169Yb, 177Lu, 186Re,
188Re, 192Ir, 241Am. Uncertainty, U, for k = 2: U < 1.0% ( 2.1% for
99mTc)
•10 radionuclides: 54Mn, 65Zn, 131I, 133Ba, 134Cs, 137Cs, 152Eu, 169Yb,
192Ir, 241Am, verified in Key comparisons. RML values compared with
calibration figures assigned, according he Key Comparison Reference
Values (KCRV). Maximum difference: 241Am (1.1%)
•Calibration performed in 2001 at PTB, Germany, by Dr. H.
Schrader, A.Luca and Al. Druker (NMI), using PTB - 2ml vials with
standard solutions, for 19 radionuclides, 11 being common. PTB IFIN-HH comparison : results agreed within uncertainties.
•Special attention for 131I , Sahagia et al. ARI 66(2008)539-544
Improvement of the electrometric system
of the chamber
• Traditional electrometric system : a set of 0.1 nF, 1nF, 10
nF and 100 nF capacitors.
- Separate calibration figures, expressed in, mV s-1 MBq-1 for
the capacitors, had to be determined, to be used for various
activity intervals.
• Since 2006, an electrometer type Keithley 6517A has
been operational.
- Parallel registrations, with both electrometers, and precise
determination of the capacitors values - performed .
- The capacitor , 1 nF - value was determined with an
uncertainty uc = 0.15%.
• The calibration figures were transferred to the new
units, pA MBq-1.
Large area multiwire, sealed proportional counter
• Used for large surface alpha and beta sources used for
measurement of surface contamination.
• Calibration - performed in terms of activity and particle
emission rate in 2πsr geometry.
- calibration in activity was performed by using standard
sources, gravimetrically prepared from 147Pm, 204Tl, 90(Sr+Y)
standard solutions
- emission rate calibration is made using sets of sources
measured directly in the upper half of the proportional counter.
- response values - determined for various source dimensions,
up to 250 mm x 250 mm.
M.Sahagia et al. Proceedings, IRPA 9 Congress, 1996, vol 3,
pp.34-36 Vienna, Austria
Methods and Equipment for preparation
of radioactive sources
• Sources and solutions for absolute (primary) standardization
- Radioactive solutions and gravimetric dilutions for other solutions.
- Sources for absolute standardization: solid VYNS sources for coincidence
method and LSC vials.
- Traditional work: a METTLER M5 micro and an analytical balance.
- Recent purchase: a set of METTLER TOLEDO certified balances, types:
MX/M (micro) and XS204/M.
• Radioactive standards for users
- various types of radioactive solutions
- solid radioactive sources, covering the main part of Romanian necessities:
alpha spectrometric sources,
large area beta sources
sets of gamma sources, of types: (i) point sources; (II)
volume solid sources, with matrices: water equivalent, soil, zeolite for
various volume samples measurement.
M.Sahagia et al. ICRM1991, Nucl.Instr. And Meth. A312(1992)236-239
Metrology services and assurance of traceability:
• Organization of national comparisons
- Environmental type, mononuclide samples, 2 comparisons, 134Cs, 137Cs, 152Eu,
M.Sahagia et al. Nucl. Instr. And Meth. A339(1994)38-42
- Radiopharmaceuticals: 131I (1994 and 2007), 57Co (1998), 99mTc (1998 and
scheduled 2008).
M.Sahagia et al. Proceedings, IRPA9 Congress, 1996, Vienna, Vol.3 pp.497-499
• Metrology services
As a B RML authorized and attested laboratory, RML performs
- legal metrological check and calibration of equipment
- standardizes radioactive sources for users (RML products, or imported).
• Accreditation by the national body, RENAR.
-
whole documentation for accreditation - submitted to RENAR
pre-assessment evaluation , according to EN ISO/IEC 17025-2005, by Mike J
Woods, IRMC Ltd., U.K.
RENAR evaluation of the documents and implementation - this year.
process is under way, with the accomplishment of corrective actions.
International cooperation
• Participation at international comparisons
for absolute and relative standardization
• Membership in international organizations
• Bilateral and multilateral projects
Participation at international comparisons for
absolute and relative standardization
• BIPM comparisons since 1962 - 60Co sources.
• Adoption of the CIPM-MRA (Mutual Recognition
Arrangement) and establishment of the Annex B, Key
Comparison Data Base (KCDB), RML is part of the
program.
• Key comparisons registrations:
(i) BIPM.RI(II)-K1: 110mAg, 133Ba, 60Co, 134 Cs , 131I .
(ii) CCRI(II)-K2: 241Am, 109Cd,139Ce, 134Cs,137Cs, 152Eu,
55Fe, 125I , 192Ir, 54Mn, 32P, 75Se, 89Sr, 204Tl, 65Zn.
(iii) EUROMET RI(II)-K2: 169Yb , 124Sb (under analysis)
• Supplementary comparisons, organized by the IAEA
CCRI(II)-S4 “Radionuclides activity measurement in
environmental samples of water, soil and grass” (2006);
CCRI(II)-S5 “TENORM” (2007); CCRI(II)-S6 - 131I
(2006) and 57Co (planned 2008)
Conclusions from comparisons
•
Classification of results:
- Very satisfactory results- our result being considered for the calculation
of the KC Reference Value (KCRV), 60Co, 152Eu,192Ir, 133Ba, 131I ( SIR
2007-2009 approval); results with small deviation from the mean: 54Mn,
65Zn, 55Fe, 204Tl
- Good results, registered in KCDB, but not in KCRV (134Cs, 241Am)
- Not satisfactory - 125I. We identified the error sources and developed a
new, coincidence, standardization method.
• The program allowed us:
- to validate our methods for absolute and relative standardization,
- to establish the equivalence of the primary Romanian Activity standards
at the level of the CIPM-MRA,
- to promote 37 Calibration and Measurement Capability (CMC) files,
for radioactivity, which were approved by all Regional Metrology
Organizations
Membership in international organizations
•IFIN-HH - Member of the International Committee for
Radionuclide Metrology (ICRM) since 1980
- RML participated regularly, starting with 1991, at ICRM conferences
and presented scientific papers.
- Dr. Enric Leon Grigorescu served as ICRM - Vicepresident, during
1990 -1994
-Dr. Maria Sahagia is in the nominating commission, 2001-2009.
Recognizing the active participation in international comparisons and
RML publication list
• The Consultative Committee for Ionizing Radiations, Section
Measurement of Radionuclides [CIPM-CCRI(II)], accepted IFINHH, as a full member, in 2004,
besides other 18 Metrology Institutes and 8 Observers
In this quality, we presented reports at the 2005 and 2007 meetings
and updated regularly the publication list.
Bilateral and multilateral collaboration
Bilateral:
CEA-DIMRI(DETECS/LNHB)-France
PTB-Germany
ENEA- Italy
Multilateral:
EC of Excellence – IDRANAP
IAEA- CRPs
Bilateral projects
• Collaboration with LNHB-France
Collaboration Agreement, concluded by the CEA-DIMRI (DETECS)/ LNHB
– France and IFIN-HH, 1993, in force until 2010
Very fruitful, all IFIN-HH, RML members worked in the LNHB and French
colleagues in IFIN-HH.
Common papers published:
-X and gamma-ray spectrometry:
A. Luca et al., Appl.Radiat.Isot. 52(2000)481-486, 56(2002)173-180, 58(2003)607610; Appl.Radiat.Isot. 60(2004)233-237
- LSC-TDCR:
A.C. Razdolescu and P. Cassette, Appl.Radiat.Isot. 60(2004)493-498;
-gas and LSC counting:
D. Stanga et. al., Appl.Radiat.Isot. 64(2006)1203-1206, P. Cassette, M. Sahagia et
al., Appl.Radiat.Isot. 64(2006)1465-1470;
-LSC-TDCR using channel photomultipliers:
C. Ivan et al., ICRM2007, Capetown, SA, Appl.Radiat.Isot. ref 4007.
New directions developed at RML:
LSC-TDCR method, Tritium gas measurement, High performance gammaray spectrometry and Nuclear Decay Data Evaluation, Radon standardization,
Use of CPMs for LSC-TDCR.
Bilateral collaboration-continued
• IFIN-HH, RML benefited of a common
calibration of the CENTRONIC IG12/20A
Ionization Chamber at PTB-Germany, in 2001
• Collaboration
with
ENEAItaly
was
accomplished by three ENEA fellowships, 20012002: Source preparation, Coincidence counting,
Surface sources measurement.
Multilateral projects
• European Commission’s Center of Excellence
InterDisciplinary Research and Applications Based on
Nuclear and Atomic Physics (IDRANAP), Contr. ICA1CT-2000-70023/12.
- Radionuclide Metrology Laboratory participated as the WP 7
- RML members worked mainly at LNHB, on thematics:
Decay Data evaluation, LSC-TDCR, Gas counting.
- Colleagues from LNHB-France, RC POLATOM-Poland, ENEA-Italy,
Institute of Hungarian Academy -Center Debrecen, worked in RML, in
the fields: LSC-TDCR, Coincidence counting, Positron emitters
obtaining and standardization.
- RML members and his visitors had an important scientific
contribution at the Conference: Applications of High Precision
Atomic and Nuclear Methods (HIPAN 2002 ) Neptun, Romania, 2002:
9 participants from WP7, 9 papers presented-published in Conference
Proceedings, Romanian Academy Editor, 2005
Multilateral Projects - continued
• International Atomic Energy Agency (IAEA)
Coordinated Research Projects (IAEA-CRP)
- CRP E2.10.05 “Harmonization of quality practices for nuclear medicine
radioactivity measurements” Contract ROM/12921/ 2004-2008
“Assurance of traceability, IAEA, IFIN-HH, hospitals, for nuclear medicine
measurements”.
RML contribution
- Participated at : two international comparisons 131I, 57Co (under way)
- Organized a national (2007) and an international (2008), Ankara-Turkey
University-Medical Faculty 131I comparisons;
99mTc comparison - 2008 scheduled;
- Participated at IAEA-TRS 454/2006,Quality Assurance for Radioactivity
Measurement in Nuclear medicine and other documents’ elaboration.
- CRP F42.006 „Updated Decay Data Library for Actinides” Contract ROM
/13341/2005-2008: „Improved decay data for important actinides”, with
details to be presented by Dr. Aurelian Luca
Conclusions
• The Radionuclide Metrology Laboratory
developed methods and equipment for absolute
standardization
• RML assured the whole traceability chain by
offering radioactivity standards and metrology
services to Romanian users.
• RML has a long tradition of participation in
international activities
• RML validated its standards by participating
in international programs of comparisons
THANK YOU!