A method to deal with correlations affecting γ counting efficiencies in analytical chemistry measurements performed by k 0-NAA

Oddone

2022

Self Cite

The k0-INRIM software is a computer program that was recently developed to automatically evaluate combined uncertainty while performing mass fraction measurements adopting the k0-standardization method of Neutron Activation Analysis. In this paper, significant developments of the adopted measurement model, following a complete revision of the detector characterization procedure, are reported. In particular, the efficiency ratio between monitor and analyte γ-emissions accounts for conversions between counting positions, extended sample geometry and self-absorption. In addition, true-coincidence summing, neutron flux gradient, moisture and blank corrections are included in the model. The developed measurement model is implemented in the latest k0-INRIM release; this greatly improves flexibility of the software in most of the common situations encountered in routine analysis without losing its inherent characteristic focused on uncertainty evaluation through propagation of covariances via sensitivity coefficients. A performance test was carried out by measuring the Au mass fraction of a cylindrical sample prepared from electronic waste material. Results obtained by counting the sample at different positions with respect to the detector end-cap are presented.

Section: Detection Efficiencymentioning

confidence: 99%

“…where b i are fitting parameters based on the detector characterization; they are evaluated as explained in [7]. In formula (iv) of Eq.…”

Section: Detection Efficiencymentioning

confidence: 99%

Developments of the k0-NAA measurement model implemented in k0-INRIM software

Oddone

2022

Self Cite

“…• is the epithermal neutron shape factor; • k = k ΔE k Δd k pos k geo k sa is the monitor to analyte efficiency ratio with k ΔE the efficiency ratio at reference counting position, k Δd the reference to nominal counting position correction, k pos the standard to sample positioning correction ratio, k geo the standard to sample geometry correction ratio and k sa the standard to sample γ-self-absorption correction ratio [7,8];…”

Section: Measurement Modelmentioning

confidence: 99%

“…Fig 8. The validation of results window where z score for certified elements are reported for each detected γ-emission in a bar chart…”

mentioning

confidence: 96%

The k0-INRIM software version 2.0: presentation and an analysis vademecum

2022

The k0-INRIM software was developed at INRIM to perform k0-standardization Neutron Activation Analysis and evaluate combined uncertainty through application of the spreadsheet method. However, the presence of some limitation made its use, as a tool for routine NAA, impractical. With the aim to participate to the 2021 IAEA k0-NAA software intercomparison to evaluate the effect on mass fraction results due to software used, the k0-INRIM was sizably updated in order to meet the agreed functionality requirements to take part to the exercise. In this work, the version 2.0 of the software is presented and a point-by-point example analysis is displayed. The software version here described is available for download together with the corresponding updated user’s manual.

“…The k0-INRIM (version 2.0, 2021) program was firstly developed to obtain results with uncertainty budgets as prescribed by the Guide to the Expression of Uncertainty in Measurement (GUM) taking into account correlations and based on the spreadsheet technique [25]. This requires the adoption of an original approach for the detector efficiency characterisation based on a fully experimental procedure without the need for Monte Carlo simulations [26].…”

Section: K0-inrimmentioning

confidence: 99%

The 2021 IAEA software intercomparison for k0-INAA

Blaauw

et al. 2022

In order to establish the variation between results in mass fractions due to software implementation, as measured by the k0-method for INAA, the IAEA has organized a software intercomparison. A complete set of test spectra and associated information was assembled. Efficiency curves, neutron spectrum parameters, correction factors and mass fractions were calculated with the participating programs (k0-IPEN, k0-INRIM, k0-DALAT, k0-IAEA and KayWin) using identical peak areas. In this paper, we report on the observed discrepancies, causes, remedies and future software developments. The test data, as well as intermediate results and observed mass fractions of the certified reference material BCR-320R “channel sediment” are available through the IAEA on request. The variations in concentrations attributed to differences between the programs were initially found to be 5.6 and 7.9%, for certified and uncertified concentrations, respectively. After the certified concentrations had been made available to the participants and they had been allowed to improve their programs, the variations found were 2.7 and 3.4%, respectively. The main identified remaining causes of variation are differences in the procedures used for detector efficiency characterisation and neutron spectrum parameter determination.