1. NiPS Laboratory INFN and Dipartimento di Fisica e Geologia University of Perugia via A. Pascoli Perugia I‐06100 Italy
2. Swiss Scientific Technologies SA rue du Rhone 59 Geneva CH‐1204 Switzerland
3. Terra Quantum AG St. Gallerstrasse 16A Rorschach 9400 Switzerland
4. University of Twente Faculty of Science and Technology and MESA+ Institute of Nanotechnology Enschede AE 7500 The Netherlands