Though the decay event was clear, the resultant track was incomplete, having left the edge of the plate. However, further images were discovered within days by Kurz's colleague, Irene Roberts. These tracks, having a length of about 600 micrometers, allowed the new pion particle's mass to be determined. This provided the substance for a paper submitted to Nature by César Lattes, Hugh Muirhead, Giuseppe Occhialini, and Powell. Kurz was credited in the caption for the original track's image. Powell was awarded the Nobel Prize in 1950.