Louis Müller-Unkel

Louis Müller-Unkel (born February 13, 1853 in Schmalenbuche , † February 23, 1938 in Rudolstadt ) was a German glass technician . He made the first hot cathode tubes, was a leader in the manufacture of photocells and is inextricably linked with the discovery of X-rays .

life and work

Following the tradition in his family, Louis Müller-Unkel learned the glassblowing trade . In 1886 he moved to the workshop of Franz Müller Beckenbauer in Bonn . This had been founded by Heinrich Geißler and had meanwhile grown into a kind of "master school", which had a very good name not only in scientific circles.

In Wolfenbüttel at that time the physicists Julius Elster and Hans Geitel were working on electrical conduction processes in gases. They needed technologically sophisticated glass structures for the production of which professional help was required. They turned to the renowned Bonn workshop. Here, the skilled craftsman Louis Müller-Unkel was entrusted with the execution of the order. Further orders followed. Müller-Unkel saw favorable conditions for an independent existence in the orders still to be expected from Wolfenbüttel. In 1888 he went to Braunschweig and opened an institute for the manufacture of chemical, physical and meteorological glass precision instruments .

The first order he carried out here for Elster and Geitel was an evacuated glass body with a fused cathode filament and an anode opposite in the form of a round metal plate as the anode. It is the forerunner of the hot cathode tubes that have long been indispensable in electronics, in this case a hot cathode diode.

Elster and Geitel researched the external photoelectric effect. In this context they came up with the invention of the photocell. The photoelectric cells were again manufactured by Müller-Unkel. He was soon able to manufacture photocells in any desired design and thus assumed a scientifically significant position.

Müller-Unkel carried out his work with high professional standards. Word got around. Heinrich Hertz , Philipp Lenard , Conrad Röntgen a . v. a. contacted the glass technician from Braunschweig. As a result, he was involved in discoveries and developments that had a profound impact on our civilization. As recent research on the history of the discovery of X-rays has shown, it was gas discharge tubes that Müller-Unkel made for Röntgen, with which he made his sensational observation of the body-penetrating radiation on the evening of November 8, 1895.

When the discovery of X-rays spread like wildfire and a huge demand for "X-ray tubes" arose, Müller-Unkel announced that he could supply tubes "exactly according to the instructions of Prof. Röntgen".

The manufacture of so-called gas discharge tubes determined the first years of his activity. The “chemical apparatus” already listed in his first company brochure, however, show that he was keen to establish more extensive contacts with scientists.

In 1913 Müller-Unkel reduced his company to a pure repair shop. In April 1931, now at the age of seventy-eight, he finally announced his business.

He spent his twilight years in Rudolstadt in Thuringia, looked after by his sister and two nieces. He died there on February 23, 1938 at the age of 85.

literature

• Günter Dörfel: Louis Müller-Unkel (1853-1938) - glass technician in Braunschweig . Braunschweigisches Landesmuseum , information and reports, 1/2003.