Contribution of the Faraday cup coupled to 1012 Ω current amplifier to uranium 235/238 and 234/238 isotope ratio measurements by thermal ionization mass spectrometry

•Determination of the 234U/238U and 235U/238U isotopic ratio by TIMS with electron multipliers detectors and Faraday cups coupled to 1012Ω current amplifying system.•Faraday cup equipped with 1012Ω current amplifier were used in order to reduce the amounts of samples deposited on the filament.•Different detector configurations were performed to obtain accurate isotope results.