| ... Das Zählrohr besteht in der Regel aus einem beidseitig abgeschlossenen Rohrstück, welches entweder aus einem elektrisch leitenden Material (Metall), oder aus elektrisch isolierendem Material (z.B. Glas), das jedoch innen elektrisch leitend beschichtet sein muss, hergestellt ist. In seinem Innere ... more... Das Zählrohr besteht in der Regel aus einem beidseitig abgeschlossenen Rohrstück, welches entweder aus einem elektrisch leitenden Material (Metall), oder aus elektrisch isolierendem Material (z.B. Glas), das jedoch innen elektrisch leitend beschichtet sein muss, hergestellt ist. In seinem Inneren befindet sich von der elektrisch leitfähigen Außenwand isoliert ein dünner Zähldraht. Dabei stellt der besagte Zähldraht die Anode, das Zählrohrgehäuse die Kathode dar. Befüllt ist der Zwischenraum mit einem Zählgas, welches das eigentliche Detektorvolumen (für Korpuskelstrahlung) darstellt. Weiterhin unterscheidet man mehrere Bautypen von ... |
| Aragonite is a calcium carbonate, chemically identical with calcite. The mineral calcite, however, differs from Aragonite due to its internal crystal structure. While the crystal system of calcite is trigonal, the system of aragonite is rhombic. Dense masses of small aragonite crystals are difficul ... moreAragonite is a calcium carbonate, chemically identical with calcite. The mineral calcite, however, differs from Aragonite due to its internal crystal structure. While the crystal system of calcite is trigonal, the system of aragonite is rhombic. Dense masses of small aragonite crystals are difficult to distinguish from calcite, but they are larger, they show a distinct habit. A lot of chapters in this portrait will give you much more details about this interesting mineral. Written and investigated by Peter Seroka. (Article in german) |
| In the late Middle Ages massive amount of Baryt which phosphoresced when it was gently heated, were discovered in Italy. This stone was named after its place of discovery "Pietra fosforica di Bologna" (phosphorescent Bologna stone) and was of great interest to alchemists. Although the name baryte ha ... moreIn the late Middle Ages massive amount of Baryt which phosphoresced when it was gently heated, were discovered in Italy. This stone was named after its place of discovery "Pietra fosforica di Bologna" (phosphorescent Bologna stone) and was of great interest to alchemists. Although the name baryte has been assigned centuries later, it may be assumed that the Bologna stone is the first description in the literature. A portrait about this famous mineral by Peter Seroka. |
| In 1978 the US - American geologist Walter Alvarez gained a narrow pattern red clay in the Italian Apennines and certain age these samples to approximately 65 million years , ie at the end of the Cretaceous period and the beginning of the Tertiary period. This very thin lime- clay layer lies between ... moreIn 1978 the US - American geologist Walter Alvarez gained a narrow pattern red clay in the Italian Apennines and certain age these samples to approximately 65 million years , ie at the end of the Cretaceous period and the beginning of the Tertiary period. This very thin lime- clay layer lies between two calcareous sediments and showed a different fossil record , which to a mass extinction ( faunal ) hinted . While further analysis Alvarez noted a high iridium concentrations; a typical ... An article by Peter Seroka (written in german) |