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Your search keyword '"López-Gutiérrez, José María"' showing total 2 results
Start Over Author "López-Gutiérrez, José María" Topic 41ca
2 results on '"López-Gutiérrez, José María"'

1. Ca-41 measurements on the 1 MV AMS facility at the Centro Nacional de Aceleradores (CNA, Spain)

Author

Vivo Vilches, Carlos, López Gutiérrez, José María, García León, Manuel, Vockenhuber, Christof, Walczyk, Thomas, Universidad de Sevilla. Departamento de Física Aplicada I, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, and Ministerio de Economía y Competitividad (MINECO). España

Subjects
41K interference, Accelerator mass spectrometry, Low-energy AMS, 41Ca
Abstract

We present a detailed study of the performance parameters for 41Ca measurements at the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA) in Seville. Mixing CaF2 with Ag, we get stable (40CaF3)− currents between 50 and 100 nA. Transmission of the 2+ state in the He stripper is 41%, while optical transmission in the HE sector is typically higher than 95%. At low energies we cannot separate 41Ca from the isobar 41K at the detector, but the interference is reduced by using (41CaF3)− ions. The remaining contribution is corrected by measurement of the other stable isotope of potassium, 39K, to estimate this interference (K-correction). After this correction, we reach a 41Ca/40Ca background level between 5 × 10−12 and 8 × 10−12, making possible measurements of 41Ca/40Ca ratios higher than 4 × 10−11. Intercomparisons with the 0.6 MV AMS system at ETH Zurich show a quite good correlation. Ministerio de Economía y Competitividad FIS2015-69673-P

Published
2017

2. Factors related to 41K interference on 41Ca AMS measurements.

Author

Vivo-Vilches, Carlos, López-Gutiérrez, José María, García-León, Manuel, and Vockenhuber, Christof

Subjects
*ACCELERATOR mass spectrometry, *POTASSIUM isotopes, *CALCIUM isotopes, *STAINLESS steel, *CALCIUM fluoride
Abstract

Abstract Dealing with the 41K interference during 41Ca measurement with low energy AMS systems is challenging. The detection of 39K to correct the measured 41Ca/40Ca ratios is a powerful tool that improves precision and accuracy. However, the study of the sources of this interference can help to reduce it to its minimum. In this work, it is shown that iron is a factor enhancing the production of the 41K interference, since the (41K57Fe)− ion has the same mass as (41K19F 3)−. To validate this observation, we measured 57Fe2+ together with 41M2+ (all ions with mass 41) and 39K2+ in a blank sample and an aluminum target at the 600 kV AMS system at ETH Zurich. We also show the temporal evolution of 41M/40Ca and 39K/40Ca ratios in two blank samples during a measurement on the 1 MV AMS system at CNA Seville. Even when unstable behavior for these ratios is observed for one of the blanks, the relationship between both, 41M/39K, is relatively stable over time. This supports the accuracy of the K–correction method, providing that it is applied sequence by sequence. Two programs, one for each of these compact AMS systems, were written in FORTRAN code to deal with the complexity of the data analysis due to the K-correction. [ABSTRACT FROM AUTHOR]

Published
2019
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