TABLE 4.2 1, CONTINUED Laboratory Activity Measurements. Class Measurement Sample Comments A , Gammaactivity, doghouse AC Gammaactivity, dip A A Gammaactivity, end-window Gammaactivity, well B Gammaactivity, 4-r ion chamber A B Mo™ assay, radiochemical Radiochemical R-values, product/fission ratios Occ, cloud Occ, cloud D Spectrometry R-values, OCC, cloud, IC A product/fiasion ratios Relative decay rates, all instruments i. occ, AOC,, AOC,-B AOC, aliquots, tank, sea water IC trays Individual particles, aliquots of most samples Aliquots of most samples Precision better than +5 parcent, except for end portion of decay curves. Aliquoting uncertainty with occasional presence of solids in high specific-activity sample. Precision better than +5 percent. Precision for single particles +3 percent (Reference 26). Some skill required in operation; precision #5 to 20 percent at twice background (Reference 26). All required Accuracy +10v percent (Reference 34). Accuracy of nuclide determination +20 to 25 percent (Reference 34). Factor of 2 or 3; misidentification possible. With few exceptions, necessary decay corrections made from observed decayrates of appropriate samples in counters desired. Laboratory Physical and Chemical Measurements Class A B D Measurement Chloride content, slurry drops Water volume, slurry drops Identification, compounds and elements of slurry solids Solid particle weights A Sample Comments IC reagent film IC reagent film IC reagent films, occ IC trays, OCC, unscheduled A Solid particle densities c Elemental composition, fallout D Identification, compounds and elements of slurry solids Particle size-frequency distributions, concentrations and relative weights versus time B-c IC trays, OCC, unscheduled occ . IC reagent film, occ IC trays Accuracy +5 percent (Reference 31). Accuracy +25 percent (Reference 31). Possible misidentification; small samples, sma)’ number of samples. Accuracy and precision +5 yg, leading to +1 percent or better on mostparticles (Reference 26). Precision better than +5 percent. Large deviations in composition from duplicate trays; recovery loss, and possible fractiona~ tion, ~ 40 mg; honeycombinterference. Possible misidentification; small samples; err ill number of samples. Difficulties in recognition of discrete particles, treatment of flaky or aggregated particles; uncertain application of defined diameter to terminal-velocity equations; tray backgrounds and photographic resolution in smaller size ranges. IV. Radiation Characteristics Data Class Item Comments A-C Gamma-ray decay schemes A-B Fission-product-disintegration rates N Computed r/br at 3 ft above infinite plane photon/tims /area versus photon energy B Absolute calibration, beta counter B Absolute calibration, doghouse counter Amount of decay scheme data available dependent on particular nuclide. About +20 percent for time period considered (Reference 41). Error assumed small comparedto errors in fallout concentration, radionuclide composition, and decay scheme data. Personal communication from J. Mackin, NRDL. Uncertainty in disintegration rate of calibrating nuclides; dependence on gamma-ray decay schemes. 125