Hans Henrik Andersen

Hans Henrik Andersen (born May 1, 1937 in Frederiksberg , Denmark ; † November 3, 2012 ) was a Danish nuclear physicist. He was a professor at the Niels Bohr Institute at the University of Copenhagen (retired 2004) and was co-editor of the scientific journal "Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms".

He has made significant contributions to various areas of atomic physics and solid state physics , in particular in the area of ​​the braking power of matter for fast charged particles. The accuracy (0.3-0.5%) of his measurements of the braking capacity of thin foils is unsurpassed to this day (2006). They were carried out by measuring the heat development in the foil at the temperature of liquid helium (−269 ° C).

In 1969 he and his colleagues succeeded in proving that the braking capacity of alpha particles is more than four times that of protons . Since the atomic number of the alpha particle is exactly twice that of the proton, this means that the braking power is not exactly proportional, as it would correspond to the simple Bethe formula . This was renewed evidence for the existence of the Barkas effect (after Walter H. Barkas , also called the Barkas-Andersen effect ). ${\displaystyle z}$ ${\displaystyle z^{2}}$

literature

• HH Andersen, H. Simonsen, H. Sørensen: An experimental investigation of charge-dependent deviations from the Bethe stopping power formula. In: Nuclear Physics A. Vol. 125, No. 1, 1969, ISSN  0375-9474 , pp. 171-175.
• Peter Sigmund: Particle Penetration and Radiation Effects. General Aspects and Stopping of Swift Point Charges (= Springer Series in Solid State Sciences. Vol. 151). Springer, Berlin / Heidelberg 2006, ISBN 3-540-31713-9 .

Individual evidence

1. ^ Obituary ( Memento from June 16, 2013 in the Internet Archive )