title: Carbon cartridge standards for 125I and suggested applications.
abstract: Carbon cartridge standards were prepared to assess the activity of 125I incident on, and adsorbed in, cartridge samples during air sampling. Each cartridge standard consisted of an 125I-spiked filter paper at a known depth, ranging from 0 to 19 mm, embedded in approximately 34 g of 20-30 mesh activated carbon contained within a 6.35 cm diameter by 2.22 cm deep metal cartridge with screened openings. The total counting efficiency values range from 17.8 to 20.8% for cartridges counted at 3.2 mm from a thin-crystal NaI(Tl) detector. The standards were analyzed using a front/back counting technique, and fitting functions were developed relating the front/back net counts ratio and counting efficiency to the 125I depth of burial. A method for determining sample activity that accounts for exponential radioiodine loading in cartridge samples is compared to a less complicated technique that assumes all the radioiodine is located at an equivalent depth of burial that is based on the sample front/back net counts ratio. In addition, methods are presented for determining airborne 125I activity for constant and variable concentrations. Variable concentrations are assumed to occur in a fume hood duct by one or more bulk releases as a result of iodinations that are performed during a given sampling interval. The two methods are shown to have maximum relative deviations ranging from -16 to +16%.
authors.affiliation: University of Massachusetts Lowell, 01854, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Tries
authors.forename: J P
authors.initials: JP
authors.lastname: Ring
authors.forename: G E
authors.initials: GE
authors.lastname: Chabot
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis* / Q000592:standards; D000465:Algorithms; D001699:Biometry; D002244:Carbon; D006283:Health Physics; D007457:Iodine Radioisotopes / Q000032:analysis* / Q000592:standards*; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000592:standards* / Q000706:statistics & numerical data
chemical_list: D000396:Air Pollutants, Radioactive; D007457:Iodine Radioisotopes; D002244:Carbon