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Nuclear Science and Technology | Progress Report  207





               Nuclear Energy Commission, according to        make the 6 mm diameter pellets (Figure 45).
               the type of the radionuclide and the practice.   The CaSO :Dy pellets are destined to the in-
                                                                        4
               Continuous improvements in IPEN’s installa-    dividual, area and environmental monitoring
               tions which handle radioactive materials have   through the thermoluminescence dosimetry.
               required actualization in safety programs.     Besides, they could be applied to the high
                                                              doses, retrospective and clinical dosimetry as
               During the period from January 2014 to De-     well as solid state dosimetry research. Pellets
               cember 2016, approximately 2,400 direct mea-   of several materials such as quartz, emerald,
               surements of both whole-body and thyroid       topaz, jade for instance can be also produced
               contents have been carried out in workers      by means of the same referred method. The
               as well as the internal dose evaluation. The   requests of CaSO :Dy crystals and pellets from
                                                                              4
               committed effective dose higher than the       many institutions have been attended by the
               annual limit on intake in this period was not   laboratory.
               achieved. In addition, the LMIV have partic-
               ipated in a research group of the National     Routine External Dosimetry
               Council for Scientific and Technological De-
               velopment which involves eight other insti-    The external dosimetry laboratory applies
               tutions.                                       the thermoluminescent (TL) technique and
                                                              CaSO :Dy based dosimeters developed at IPEN
                                                                   4
               Dosimetric material production                 to carry out individual, area and environmen-
               - pellets of CaSO :Dy                          tal monitoring.
                               4

               The Dosimetric Materials Laboratory devel-     The individual monitoring service is autho-
               oped and patented the CaSO :Dy crystals        rized by the Brazilian Nuclear Energy Com-
                                              4
               growth system and the method to produce        mission - CNEN by mean of the Essays and
               the Teflon ® sintered pellets. The CaSO :Dy    Calibration Services Evaluation Committee
                                                       4
               crystals grow in the sealed system and are     -  CASEC.  It completely satisfies CNEN’s reg-
               cold pressed with the binding material to      ulatory norms, besides presenting a brake in
                                                              IPEN’s quality control system, being respon-
                                                              sible for the external exposure monitoring
                                                              of all occupationally exposed individuals at
                                                              IPEN, other autarchies, governmental offices
                                                              and even some private facilities.


                                                              The area and environmental monitoring are
                                                              performed to different society sectors, such
                                                              as research institutes, universities and private
                                                              foundations and companies.

                                                              High Dose Dosimetry


                                                              Alanine/Electron Paramagnetic Resonance
                                                              (EPR) dosimetric system provides a second-
               Figure 45- CaSO :Dy dosemeters.                ary standard for routine radiation dosimetry
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