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| ACTIVITY OF RADIONUCLIDES
LABORATORY |
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Quantity - activity.
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Unit - Bq (becquerel).
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Tasks
of the laboratory |
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The main task
of the Laboratory is the realisation of the unit of
radionuclide activities and its transfer to user's
instruments. Derived quantities used are mass activity,
volume activity and surface activity in corresponding
units.
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International
comparisons |
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CCRI (II)
comparison of 152Eu activity measurement (BIPM
1999-2000). DUNAMET D29 common calibration of ionizing
chambers (CMI 2001).
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Available
metrological services |
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Radionuclides
calibrators verification (mainly to nuclear medicine
laboratories). Instruments are tested to fulfill STN 40
4014 standard requirements of 10 % expanded uncertainty in
the range from 1 MBq up to 100 GBq. |
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Gammaspectrometers
verification. Semiconductor detectors used in
gammaspectrometry are verified in according with IEC 973 standard. |
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Verification
of monitoring equipment in liquid effluents. tests of
calibration and linearity are made in according with IEC
861 standard (15 % expanded uncertainty). |
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Verification
of surface contamination monitors. Alpha and/or beta
surface contamination monitors are tested for 14C,
60Co, 90Sr, 137Cs, 204Tl
and 241Am calibration in according with STN 35
6566 standard (25 % expanded uncertainty). |
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Sealed
sources standardization and certification. Sealed sources
activity can be by 4 ionizing chamber measurement. The chamber has
bee traced directly to some PTB standards. |
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Methods of measurement: |
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radionuclide calibrators are verified in situ with a
travelling standard ionization chamber using
radionuclides provided by users. Standard measurement
conditions are given using standard containers (injection
ampoules or peniciline vials) filled by 2 - 5 ml of
radionuclide solution;
- gammaspectrometers are verified by calibrated water
solutions of several radionuclides sent to users. Liquid
effluent monitors are verified by calibrated 137Cs
low-activity water solutions and a set of 137Cs
solid standards. Contamination monitors are tested by
certified large area sources checked by a standard
instrument. |
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Instruments
in use |
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Basic instrument for activity measurement is
calibrated 4
(re-entrant) pressurized ionizing chamber. Low gama
activity measurements and radionuclide purity testing are
made by calibrated gammaspectrometric system with HPGe
detector. set of large area (110 x 150) sources is
available together with a verification instrument with
two thin-window proportional counters. |
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