Accelerator mass spectrometry: high sensitivity for radionuclides detection

A. ARAZI; D. ABRIOLA; O. CAPURRO; M.A. CARDONA; E. DE BARBARÁ; J. FERNÁNDEZ NIELLO; J. GARCÍA GALLARDO; F. GOLLAN; D. HOJMAN; G. MARTÍ; A. NEGRI; A. PACHECO; D. RODRIGUES; N. SAMSOLO; M. TOGNIERI

Bariloche

Workshop; 13th Workshop on Separation Phenomena in Liquids and Gases; 2015

Comisión Nacional de Energía Atómica

The Accelerator Mass Spectrometry (AMS) is the most sensitive technique for the detection of long-lived radioisotopes (or even stable nuclides), being capable of detecting one radioactive atom among 1015 of its stable isotope. In addition, this can be performed on samples smaller than 1 mg. The improvement of AMS over the conventional Mass Spectrometry (MS) relies on the use of a tandem accelerator after the first stage of magnetic mass selection. On one hand, interfering isobaric molecules are completely destroyed by the accelerator stripper, circumventing the major background contribution when MS is used. On the other hand, the high energy supplied by the accelerator to the particles allows the discrimination of interfering isobaric nuclides by means of detectors commonly used in nuclear physics research. The AMS technique has proved to be highly successful in detecting many long-lived radioisotopes which are useful in very diverse areas such as archeology (14C), geology (10Be, 26Al), hydrology (36Cl), nuclear safety and radioactive pollution control (129I), astrophysics (53Mn, 60Fe), and nuclear safeguard (236U). In this talk we will introduce the basic aspects of this technique, give some examples of its application and resume recent measurements performed at the TANDAR Accelerator, including measurements of the 235U/238U ratio on nanograms samples.