Jan Kazimierz Danysz

He was an assistant of Maria Skłodowska-Curie and notable in the development of beta spectrometry.

Danysz made considerable advances on the magnetic deflection techniques of Baeyer, Hahn and Meitner, placing the source (he used radium) in a capillary tube under a slit, with a photographic plate in the same horizontal plane.

By this means the known number of lines (later understood to be conversion lines) superimposed on the beta energy spectrum of RaB + RaC went from 9 to 27 (later work by Robinson and Rutherford found 64; 16 from RaB and 48 from RaC).

[1] He finished his doctoral thesis in 1913, and by 1914 he was considered by Rutherford as a leading researcher into beta decay,[2] but he did no further work.

[3] J. Danysz, Le Radium 9, 1 (1912); 10, 4 (1913) Danysz, J. Recherches expérimentales sur les β rayons de la famille du radium Ann.