Time of Flight system to investigate positronium cooling L. Di Noto, S. Mariazzi, M. Bettonte, G. Nebbia and R.S. Brusa Eur. Phys. J. D, 66 5 (2012) 118 Published online: 17 May 2012 DOI: 10.1140/epjd/e2012-20674-7