Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MS: Fachverband Massenspektrometrie
MS 8: Isobar Suppression Techniques
MS 8.4: Vortrag
Freitag, 6. März 2026, 12:00–12:15, N 6
Design and optimization of a ΔE-Eres gas ionization chamber for Be-10 isobar suppression at low energies. — •Samuel Marty, Arnold Müller, Christof Vockenhuber, Andreo Crnjac, René Gruber, Daniel Hösli, and Marcus Christl — Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, Zurich, Switzerland
Contrary to C-14 and its isobar N-14, the radioisotope Be-10 has a large isobaric background due to B-10 being able to form negative ions. There are various ways to suppress this unwanted signal: degrader foils, extracting BeF instead of BeO, and finally a detection method which exploits the difference in energy loss. One such method is the ΔE-Eres gas ionization chamber, which has been used at ETH since the 2000s. However, most of the deployed detectors operate in ionization mode, where the primary electrons are measured directly. By increasing the field strength, the detector can be brought into proportional mode, where avalanche formation greatly enhances the signal-to-noise ratio. Particularly at low energies, significant improvements to the detector resolution can be achieved for light elements. Moreover, the detector does not necessitate cooled preamplifiers anymore. To confirm this claim, the energy resolution for both modes was measured using a variety of particles. Additionally, the multiplication factor as a function of the field contains information on the first Townsend coefficient of hexane, a key parameter for gas multiplication. Finally, the stability of gas ionization detectors operating in the proportional regime was studied.
Keywords: Gas ionization chamber; Proportional regime; Resolution at low energy; Townsend multiplication; Be-10 background suppression