E-ToF Measurements with Calorimetric Low Temperature Detectors for Stopping Power Determination and Mass Identification of Low Energy Heavy Ions
Dr. Artur Echler (Institut für Atom- und Molekülphysik, Universität Gießen)

Precise data on stopping powers (dE/dx) of heavy ions in matter are needed in many fields of basic and applied science. Using a combined energy and time-of-flight (E-ToF) measurement, calorimetric low temperature detectors (CLTDs) have been applied to determine precise stopping powers of 0.05 – 1.4 MeV/u 238U- and 131Xe-ions in carbon, nickel and gold. The high energy resolution and energy linearity of CLTDs allowed a reduction of calibration errors and an extension of the accessible energy range towards lower energies, as compared to conventional setups using ionization detectors for the energy measurement. Moreover the coincident E-ToF measurements enabled to investigate the resolution of the detector system for direct in-flight mass determination of low energy heavy ions. Due to the excellent energy resolution of CLTDs, mass resolutions down to ∆m(FWHM) = 1.3 u could be obtained for 0.1 – 0.6 MeV/u 238U-ions. Using ionization detectors in an E-ToF measurement similar values cannot be reached in that mass and energy range due to the limitations of energy resolution by statistical fluctuations of energy loss processes during particle detection. The detection concept of CLTDs, the experimental methods as well as results from latest measurements will be presented.