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  • Author or Editor: S. Goodwin x
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Abstract  

The rates at which six small aminopolycarboxylate chelates of trivalent111In and three protein-bound chelates of111In deliver indium to the serum protein transferrin have been studied in sterile human serum at pH 7.3, 37°C. Sterically hindered chelates containing a substituent on an ethylene carbon of EDTA decompose with rates in the range 0.03 to 0.11% per day—one to two orders of magnitude slower than other chelates. Only small differences are observed between rates of decomposition for low-molecular-weight chelates and for protein-bound chelates having analogous structures.

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Abstract  

A portable, battery-powered, multichannel analyzer (MCA) for use with Ge spectrometers has been developed for in-field use for the assay of x-and γ-ray emitting radionuclides. The spectrometer is capable of operating to rates greater than 150,000 counts per second. The analyzer is a Canberra InSpector MCA, that is equipped with the INEEL ultra-stable dual-energy pulser, and pulse injection with subsequent removal (PISR) circuitry. PCGAP, a set of MCA control and spectral analysis programs, was developed for use on a PC with a Windows NT Operating System. It includes an interactive peak analysis program as well as automatic spectral analysis programs for the X- and γ-ray regions, and a number of utility programs. The pulser peaks are calibrated with radioactive sources in terms of energy (i.e., their energy equivalents are measured) using the PCGAP spectral analysis package so that energy shifts, including those due to changes in temperature or count rate, do not cause a loss of energy calibration. The number of injected low- and high-energy-equivalent pulses is known so the stored pulser pulses can be used for a dead-time and random summing correction. The pulser peaks are also used to monitor any deterioration in spectral quality caused by noise, ground loops, etc. The results of performance tests to demonstrate the capabilities of this pulser-equipped InSpector are reported.

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Abstract  

The cleanup of high-level defense nuclear waste at the Hanford Site presents many challenges. These include removing and disposing of components from buried active waste tanks to allow new equipment insertion or hazards mitigation. This paper discusses a unique automated system that provides for retrieval, high-pressure washing, inventory measurement, and containment for disposal. Key to the inventory measurement is a three-detector high-purity germanium high-performance gamma-spectroscopy system capable of recovering data at up to 90-percent saturation (200,000 counts/s). Data recovery is based on a unique embedded electronic pulser and special software to report the inventory. Each detector has different shielding specified through simulation using the Monte Carlo computer code for N-particle transport modeling. This shielding provides performance over a dynamic range of eight orders of magnitude. This paper covers system description, calibration issues, and operation.

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