Attempts in search for superheavy elements in nature II

摘要

The search for superheavy elements is continued. We chose minerals for long- time exposure in a sandwich arrangement (PAD [polyallyldiglycol carbonate] and mica). In a first step we investigated samples of manganese concretions from the Pacific Ocean, enriched samples from Salton Sea and a volatile by product - fraction of copper - shale. (Kupferschiefer) from Mansfeld (,,Theisenschlamm''). After an exposure time of 535 days or 326 days, respectively, and proper etching, the SSNTD's were scanned using an optical microscope. Tracks due to the fission fragments could be seen neither at the PAD nor at the mica surface. The most hopeful sample,,Theisenschlamm" gives about 1.2 x 10(6) tracks of alpha - particles at PAD. This can be explained by the uranium content. The exposure will be continued and other samples will be investigated, too. [References: 12]