Optimization of 10Be measurements at the 6 MV AMS facility DREAMS

We investigated benefits from raising the ion beam energy during measurements of 10Be with Accelerator Mass Spectrometry (AMS) at the 6MV DREAMS (DREsden AMS) facility. Increasing the terminal voltage to ≥5MV hardly reduces the yield of the Be2+ charge state after the accelerator if one applies only a thin Ar gas stripper and makes use of an overpopulation of the 2+ charge state with respect to the expected equilibrium charge state yield. As a further stripping to the 4+ charge state is conducted in a degrader foil after the analysing magnet, it is desirable to hit the foil with the highest available velocity in order to have optimal stripping of Be2+ to the fully stripped ion. At DREAMS the 10Be yield can be improved by a factor of 1.36. Applying a terminal voltage of 5.8MV the transport efficiency of 10Be from the ion source to the detector is ca. 32.5%.