Selective laser photodetachment in an RFQ ion beam cooler for AMS
by
Johanna Pitters(University of Vienna)
→
Europe/Zurich
CERN
CERN
Description
AMS (Accelerator Mass Spectrometry) is the most sensitive method for measuring trace amounts of long-lived radionuclides. A major challenge in AMS is the suppression of stable isobars that interfere with the radioisotope of interest. A new technique for element-selective filtering of negative ion beams has been developed at the VERA (Vienna Environmental Research Accelerator) Laboratory at University of Vienna. It is going to be installed as an extension to the existing AMS facility and will enable the measurement of radionuclides that are currently inaccessible to AMS.
The method uses laser photodetachment of negative atomic or molecular ions. The unwanted isobar can be neutralized by a high intensity laser beam of appropriate wavelength, provided that the detachment energy of the radioisotope of interest is higher than the one of the unwanted isobar. The ions are decelerated and cooled down to thermal energies by a He buffer gas inside an RFQ ion beam cooler in order to extend the ion-laser interaction time to several ms.
In this talk, I will give a detailed description of the cooler and discuss experimental results concerning transmission of the ion beam through the cooler system and efficiency of optical filtering.
