ABSTRACT
Alpha-emitting 238Pu and 241Am sources on stainless steel substrates have been prepared using a new electrodeposition method based on an ammonium oxalate-ammonium sulfate electrolyte containing diethyl triamino pentaacetic acid. The deposition yield is determined by measuring the activity of the sources using a high-efficiency 2pi alpha proportional counter and a backscattering chamber designed and fabricated for this purpose. Optimal electrodeposition parameters have been determined for 241Am, enabling manufacture of standard alpha-emitting sources with minimal radioactive waste.
Subject(s)
Alpha Particles , Electroplating/methods , Electroplating/standards , Radiation Monitoring/standards , Reference Standards , Reference Values , Americium/analysis , Americium/chemistry , Americium/standards , Guidelines as Topic , Korea , Plutonium/analysis , Plutonium/chemistry , Plutonium/standards , Radiation Dosage , Radiation Monitoring/instrumentation , Radiation Monitoring/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
We have developed, as a national standard, a windowless multiwire proportional counting (MWPC) system for gross measurements of alpha- and beta-emitting radionuclides at an uncertainty level below 1%. Various detector characteristics have been studied and several working parameters of the system have been determined in order to achieve an optimized detection capability. The detector is commissioned through an international comparison of the beta emission rate from an extended area (36)Cl source. Correction for the dead time loss is made by the non-extendable dead time method. A linear extrapolation of pulse height spectrum is employed to correct for the loss in the detection efficiency due to discriminating against the events formed from a small number of original ion pairs. The surface emission rate was measured to be 1.84 x 10(3) counts/s with the relative combined standard uncertainty of 0.46%. The measured uncertainty indicates that the constructed MWPC is capable of serving as a national standard.
