A new AMS facility MILEA at the Nuclear Physics Institute in Řež, Czech Republic

Abstract

The performance of a new Multi-Isotope Low-Energy AMS (MILEA) system developed in a cooperation of Ionplus AG and ETH Zurich, Switzerland for determination of ¹⁰Be, ¹⁴C, ²⁶Al, ⁴¹Ca, ¹²⁹I, and actinoids (²³³U and ²³⁶U) is described based on results of factory- and on-site acceptance tests carried out at the producer and customer sites, respectively. The parameters measured were transmissions from the injector to the detector, currents in the high energy part of MILEA, radioisotope/stable blank ratios or abundance sensitivity, single sample and overall sample scatter of the radioisotope/stable isotope ratios. The results achieved were competitive with larger AMS systems.

Introduction

Applications of accelerator mass spectrometry (AMS) for determination of long-lived naturally occurring and man-made radionuclides at ultra-trace levels are continuously increasing in mutual synergy with research and development of technology and related scientific fields. New, compact and multipurpose AMS systems with improved types of ion sources, accelerators and detectors are being designed and produced following intensive scientific progress, as has been predicted by several authors [1], [2], [3]. Low-energy (LE) AMS systems with terminal voltages in the sub-500 kV range have recently become available [4], [5], [6], [7], [8], [9], [10], [11] bringing significant economic advantages. The majority of LE AMS systems are dedicated ¹⁴C machines, which are capable of providing high measurement efficiency, stability and reproducibility even at accelerator voltages down to 50 kV [12]. But also, an increasing number of compact LE AMS systems were established in recent years, which retain the multi-isotope capabilities with good detection limits, as also demonstrated in this work.

A consortium of Nuclear Physics Institute (NPI) of the Czech Academy of Sciences (CAS), Faculty of Nuclear Sciences and Physical Engineering of the Czech Technical University in Prague (CTU in Prague – FNSPE) and the Institute of Archaeology of the Czech Academy of Sciences, Prague (IAP) has recently acquired a 300 kV Multi-Isotope Low-Energy AMS system (MILEA). The MILEA system was developed in a collaboration of Ionplus AG and ETH Zurich, Switzerland. It has been designed, but not limited to, for determination of ¹⁰Be, ¹⁴C, ²⁶Al, ⁴¹Ca, ¹²⁹I, U, Pu and other actinoids. This device serves for a national project “Ultra-trace isotope research in social and environmental studies using accelerator mass spectrometry”, acronym RAMSES [13]. MILEA installation has recently been completed in the first Czech AMS laboratory located at NPI, Řež. Here, we report the experience of the first MILEA installation outside of Switzerland. The performance of this next generation multi-isotope AMS facility is reported in terms of factory- and on-site acceptance tests, FAT and SAT, respectively, for the radionuclides ¹⁰Be, ¹⁴C, ²⁶Al, ¹²⁹I, ^233,236U. The system performance was evaluated by means of the following parameters: transmissions from the injector to the detector, abundance sensitivity, the rare/stable isotope blank ratio, single sample and overall sample scatter of the radioisotope/stable isotope ratios.