Improvement in the Rigidity Resolution at Low Rigidities with the New Track Fitting Algorithm

At low rigidities (<10 GV), we have implemented a new track fitting algorithm based on the Kalman filtering technique. It more accurately accounts for energy losses and multiple scattering by charged particles, see C. Höppner, S.  Neubert, B. Ketzer, and S. Paul, Nuclear Inst. and Methods in Phys. Res., Sect. A 620, 580 (2010).

With this algorithm, the measurement of nuclei with AMS in terms of rigidity resolution was significantly improved up to ~10 GV, as shown in Figure 1. This is particularly important for the AMS anti-matter such as antideuterons and anti-He as well as the nuclei isotope analyses such as ³He/⁴He, ⁶Li/⁷Li, ⁹Be/¹⁰Be and ¹⁰B/¹¹B.