TY - JOUR AU - Reynaldo, S. R. AU - Benavente, J. A. AU - Da Silva, T. A. PY - 2013/08/26 Y2 - 2024/03/29 TI - Characterization of an extrapolation chamber as a primary standard dosimeter for beta radiation JF - Scientia Plena JA - Sci. Plena VL - 9 IS - 8(b) SE - DO - UR - https://www.scientiaplena.org.br/sp/article/view/1551 SP - AB - <div>Inbeta or electron radiation fields, operational dose equivalent quantities, based on absorbed dose in</div><div>tissue, are used for radiation protection of the workers. Low penetration and high scattering in matter are</div><div>characteristics of beta radiation that make its dosimetry more complex. Reliable measurements of</div><div>absorbed dose in tissue must be traceable to an extrapolation chamber, which is the only primary standard</div><div>dosimeter available for beta radiation. This ionization chamber uses the extrapolation to zero volume as</div><div>the method of measurement of absorbed doses in 0.07 mm of tissue, DT(0.07);its requires the</div><div>determination of correction factorsrelated to influences from the detector itself and from the radiation</div><div>field geometry. In this work, a 23392 model PTW extrapolation chamber was characterized by</div><div>determining its collector electrode area, its true-null depth and the influence in its response of</div><div>temperature, humidity and chamber depth. Values of the true-null depth were 0.46&plusmn;0.04 mm and</div><div>0.40&plusmn;0.04 mm for 90Sr/90Y and 85Kr beta field sources, respectively. Corrections of the chamber</div><div>ionization current, according to the ideal gas law significantly reduced the high influence of temperature;</div><div>air humidity influence showed to be negligible within the 50% to 70% range. The high dependence of the</div><div>chamber response with its volume addressed the need to determine accurately its true-null depth. These</div><div>results are to be used as appropriate corrections for accurate absorbed dose in tissue determination.</div> ER -