Background
Coster was born on October 5, 1889, in Amsterdam, Netherlands, the son of Barend Coster, a blacksmith, and Aafje van der Mik. He grew up in Amsterdam in a large working-class family.
Mekelweg 5, 2628 CD Delft, Netherlands
From 1916 to 1920 Coster was assistant of Lodewijk Siertsema and Wander de Haas at the Delft University of Technology, where in 1919 he obtained an Engineer's degree in electrical engineering. In 1920 and 1921 he did research at Lund University under Manne Siegbahn, on X-ray spectroscopy of different elements. Coster's thesis was on this subject, and he obtained his Ph.D. degree in 1922 in Leiden under Paul Ehrenfest; his thesis was entitled "Röntgenspectra en de atoomtheorie van Bohr" (X-ray spectra and Bohr's atomtheory).
Rapenburg 70, 2311 EZ Leiden, Netherlands
With the aid of private support Coster was able to study mathematics and physics at the University of Leiden, first having passed the exams required for students who had no gymnasium education. In Leiden he was influenced by the inspiring lectures of Paul Ehrenfest, and in 1916 he obtained his Master of Science degree.
New York City, New York, United States
From 1904 to 1908 Dirk went to the Teacher's College in Haarlem.
Rapenburg 70, 2311 EZ Leiden, Netherlands
With the aid of private support Coster was able to study mathematics and physics at the University of Leiden, first having passed the exams required for students who had no gymnasium education. In Leiden he was influenced by the inspiring lectures of Paul Ehrenfest, and in 1916 he obtained his Master of Science degree.
Mekelweg 5, 2628 CD Delft, Netherlands
From 1916 to 1920 Coster was assistant of Lodewijk Siertsema and Wander de Haas at the Delft University of Technology, where in 1919 he obtained an Engineer's degree in electrical engineering. In 1920 and 1921 he did research at Lund University under Manne Siegbahn, on X-ray spectroscopy of different elements. Coster's thesis was on this subject, and he obtained his Ph.D. degree in 1922 in Leiden under Paul Ehrenfest; his thesis was entitled "Röntgenspectra en de atoomtheorie van Bohr" (X-ray spectra and Bohr's atomtheory).
Coster was born on October 5, 1889, in Amsterdam, Netherlands, the son of Barend Coster, a blacksmith, and Aafje van der Mik. He grew up in Amsterdam in a large working-class family.
From 1904 to 1908 Dirk went to the Teacher's College in Haarlem. With the aid of private support, he was able to study mathematics and physics at the University of Leiden, first having passed the exams required for students who had no gymnasium education. In Leiden, he was influenced by the inspiring lectures of Paul Ehrenfest, and in 1916 he obtained his Master of Science degree. From 1916 to 1920 Coster was assistant of Lodewijk Siertsema and Wander de Haas at the Delft University of Technology, where in 1919 he obtained an Engineer's degree in electrical engineering. In 1920 and 1921 he did research at Lund University under Manne Siegbahn, on X-ray spectroscopy of different elements. Coster's thesis was on this subject, and he obtained his Ph.D. degree in 1922 in Leiden under Paul Ehrenfest; his thesis was entitled "Röntgenspectra en de atoomtheorie van Bohr" (X-ray spectra and Bohr's atom theory).
Coster's first post was as a teacher in a primary school. A fellowship later enabled him to work on precision X-ray spectroscopy from 1920 to 1922 in Manne Siegbahn’s laboratory at Lund and from 1922 to 1923 with Niels Bohr in Copenhagen. Here he completely worked out the linking up of X-ray experimental data with Bohr’s theory of atomic structure and the periodic table of the elements. His crowning achievement was the discovery in 1923, with G. von Hevesy, of the element hafnium (named after Copenhagen and having the atomic number 72). They worked along lines suggested by Bohr, who expected the element to be a homologue of zirconium (atomic number 40) and rather different in chemical behavior from the rare earth metals (lanthanides, atomic numbers 57-71) that precede it and are very similar to each other because the “inner” shell of fourteen 4f-electrons is gradually filled. Hevesy concentrated the new element from zirconium compounds, in which it occurs naturally, as Bohr had suggested. The enrichment was checked by Coster, using the X-ray spectrum as an indicator. This was rendered more difficult by a freak of nature that made the two strongest hafnium lines coincide almost exactly with the second-order reflections of the two zirconium Kα lines, thus camouflaging its presence in zirconium compounds.
Following his return to the Netherlands, Coster was assistant to Lorentz at the Teyler Laboratory in Haarlem until 1924, when he was called to the chair of experimental physics at Groningen University; he held the chair until 1949. With a rather limited budget he modernized and extended the physics laboratory, not only introducing X-ray work but also mounting a Rowland grating for studying band spectra, mostly of diatomic molecules. He attracted Dieke and Lochte-Holtgreven as skilled experimenters in this field and R. Kronig as a general modern theorist. Zernike was already doing classical work in interference theory and infrared spectroscopy. The X-ray work was carried on by a staff including Prins, Druyvesteyn, and van der Tuuk, as well as a steadily increasing stream of students (including Wolff, Veldkamp, and Knol) and visitors (including Hanawalt, Nitta, and Smoluchowski). Among the new results were the anomalous dispersion and scattering of X rays in the neighborhood of an absorption edge. This effect was later used by Bijvoet to determine the absolute left-hand or right-hand configurations in crystals, which are difficult to obtain from other data.
Another major new point was the elucidation of the fine structure of absorption edges, extending some hundreds of electron volts from the main edge and resulting from the alternation of greater and lesser “ease” with which the crystal lattice accepts the ejected electrons. This explanation arose when the wave theory of the electron was in statu nascendi and Kronig (with Sir William Penney) applied it for the first time to the alternation of forbidden and allowed energy ranges in a one-dimensional model of a crystal. The discovery of a special kind of Auger effect, in which a secondary electron is ejected by a primary energy difference between two states having equal principal quantum numbers, also resulted from the collaboration of Coster and Kronig.
In band spectra and ultrasoft X-ray spectra, interesting new results were obtained. Appreciable work was done in neutron and nuclear physics. One gifted pupil, Hugo de Vries, became a specialist in biophysical applications of nuclear and nonnuclear physics, such as carbon-14 dating and the study of the nervous organs of fishes.
Coster was politically involved. In 1938 he traveled to Berlin to convince Lise Meitner that she had to leave Germany to escape the persecution of the Jews. Together they went by train to Groningen; at the Dutch border, Coster persuaded German immigration officers that she had permission to travel to the Netherlands. From there she went on to Sweden by way of Copenhagen.
During the German occupation of Holland, Coster also helped Jews hide from the Nazis and listened to the BBC on a daily basis using a bicycle-powered radio.
Coster was not only an energetic executive but also the moving force of his laboratory, eager to acquire mental pictures of the atomic processes and to explain them in simple terms. He was less interested in mathematical subtleties but never accepted a hazy presentation. The last years of his directorship and teaching were burdened by a progressive spinal disease, resulting ultimately in total paralysis.
On February 26, 1919, Coster married Lina Maria Wijsman, who held a degree in Oriental languages. Eventually, she was one of the first women to obtain a doctorate degree in this field from the University of Leiden. Dirk and Miep had two sons and two daughters: Hendrik, Ada, Els, and Herman.