Rapid processing of ⁸⁵Kr/Kr ratios using Atom Trap Trace Analysis

Abstract

We report a methodology for measuring 85Kr/Kr isotopic abundances using Atom Trap Trace Analysis (ATTA) that increases sample measurement throughput by over an order of magnitude to six samples per 24 h. The noble gas isotope 85Kr (half‐life = 10.7 years) is a useful tracer for young groundwater in the age range of 5–50 years. ATTA, an efficient and selective laser‐based atom counting method, has recently been applied to 85Kr/Kr isotopic abundance measurements, requiring 5–10 μL of krypton gas at STP extracted from 50 to 100 L of water. Previously, a single such measurement required 48 h. Our new method demonstrates that we can measure 85Kr/Kr ratios with 3–5% relative uncertainty every 4 h, on average, with the same sample requirements.

Stellar s -process neutron capture cross sections on Kr78,80,84,86 determined via activation, atom trap trace analysis, and deca

“…It should be noted that by conducting this reference measurement on the same day as the sample measurement we eliminate systematic effects on isotope ratios related to slow drifts in laser alignment and conditions in the atom source, which can vary at the percent level over the course of several days. The only difference then between the sample and reference measurements is that the reference gas is measured with gas constantly flowing through the system (i.e., not recirculated) in order to avoid cross-contamination of the reference gas with the irradiated sample (see [54,55] for details). In order to account for any systematic difference between these two modes of gas flow during an analysis, additional measurements are conducted where the reference gas is treated as if it were a sample.…”

“…The reference gas was recently validated by an inter-laboratory comparison [56]. Additionally, the University of Bern has also provided TRACER a series of samples spanning over an order of magnitude in 85 Kr isotopic abundances, to validate the linearity of the measurement technique [52,55]. For 81 Kr, the reference gas is the 81 Kr isotopic abundance in modern atmospheric Kr.…”

Atmospheric 81Kr as an Integrator of Cosmic‐Ray Flux on the Hundred‐Thousand‐Year Time Scale

“…In addition to trapping these two radioactive isotopes, ATTA‐3 is also used to trap and measure the loading rate (R 83 ) of the stable isotope 83 Kr for normalization (Jiang et al, ; Jiang et al, ) The ratio R 81 /R 83 is proportional to the isotopic abundance A 81 . The ATTA‐3 apparatus has demonstrated the ability to measure this ratio with 1% precision, given sufficient atom counting statistics (Zappala et al, ).…”

Online monitoring of atmospheric krypton-85 with hourly time resolution

“…Analysis of 85 Kr in environmental samples with ATTA has been realized. 26,27 More recently, fast ATTA analysis of 85 Kr activities at the 3% precision level on a 1 L STP (Standard Temperature and Pressure) air sample with 1.5 hour turnaround time has been realized in Gao et al 2021. 29 However, continuous operation has not been possible in that work since air sampling, Kr extraction and 85 Kr measurement work separately on discrete sample with attended operation.…”

“…The laser-based Atom Trap Trace Analysis (ATTA) technology is a method for measuring the 85 Kr activities of small air samples (liters) quickly. [24][25][26][27][28] In ATTA, the 85 Kr atoms are selectively captured by a resonant laser trap and counted by detecting their uorescence. Analysis of 85 Kr in environmental samples with ATTA has been realized.…”