Siemens Aktiengesellschaft

Ernst W Haas

Joachim Martin

Manfred Schnoeller

Konrad Reuschel

Heinz Mitlehner

Reinhold Kuhnert

Karl Platzoeder

Gunter Raab

Manfred Schnoller

Joachim Burtscher

Heinz-Herbert Arndt

Hellmuth Beyer

Gustav Fischer

Roland Hofmann

Nikolaus Neudert

A method for recycling metal parts contaminated by radioactive elements, in particular by .alpha.-emitters, includes forming a melt and a slag from the metal parts and then separating the slag from the melt. The radioactive elements are oxidized prior to the formation of the melt and the slag. For that purpose, the contaminated metal parts are exposed to an oxygen-containing atmosphere for a period at a temperature below the melting temperature of the metal parts.

Method for recycling contaminated metal parts

A method for reprocessing metal parts that are radioactively contaminated with uranium includes smelting the metal parts so that a melt and a slag are formed. U.sub.235 -depleted uranium is admixed with the metal parts and/or the melt and/or the slag. It is contemplated for the U.sub.235 -depleted uranium to be admixed in the form of uranium glass.

Method of reprocessing metal parts radioactively contaminated with

A waste disposal site, such as an ultimate disposal site for radioactive substances, includes installed waste having hollow spaces remaining therebetween. Packing material fills the remaining spaces. At least one substance to which gaseous toxic substances such as radioactive gases adhere, is admixed with the packing material.

Waste disposal site, in particular for the ultimate disposal of

A method for manufacturing regions having adjustable uniform doping in silicon crystal wafers by neutron irradiation according to the reaction Si.sup.30 (n,.gamma.) Si.sup.31 .beta..sup.- P.sup.31 includes the steps of covering the silicon crystal wafer with neutron-absorbing materials of different thicknesses during the irradiation, and selecting materials having isotopes having a high absorption cross-section which yield stable isotopes in the nuclear reaction having small or short-lived activity. Suitable isotopes are B.sup.10, Cd.sup.113, Sm.sup.149, Gd.sup.155 and Gd.sup.157. The regions are generated photolithographically. By such specific material selection, very small layer thicknesses can be used and microfine surface zones or areas can be doped with high geometrical precision and large penetration depth. The method is particularly suited for manufacturing power thyristors.

Method for manufacturing regions having adjustable uniform doping in

A method is disclosed for the production of n-doped silicon single crystals, each having a dish-shaped specific electrical resistance profile in a radial direction about a central axis of the crystal. A silicon single crystal is exposed to a pattern of radiation with neutrons according to the reaction 30.sub.Si (n,.gamma.) 31.sub.Si .sup..beta.-.fwdarw. 31.sub.P. The neutron radiation causes a weaker doping concentration in marginal regions of the crystals due to the production of fewer phosphorus atoms. Either p-conductive silicon crystals or n-conductive silicon crystals may be utilized as an initial material for exposure to the neutron radiation.

Method for the production of n-doped silicon with a dish-shaped profile

An apparatus for doping a semiconductor crystalline rod by nuclear or radiogenic reactions comprised of a hollow irradiation housing having axially and rotatably movable rod support means within the chamber thereof and a neutron conductive sleeve connected with the housing and providing communication between a neutron source and the housing chamber. Accurate and controlled doping of a semiconductor crystalline rod mounted on the rod support means within the housing chamber occurs via controlled rod movement in relation to the neutron source.

Apparatus for doping a semiconductor crystalline rod

Si monocrystals of the n-type are produced by zone melting polycrystalline Si rods under conditions sufficient to produce monocrystal rods, measuring the specific conductivity of such monocrystal rods and subjecting such monocrystal rods to a controlled radiation by thermal neutrons based on the measured conductivity to produce a desired degree of n-conductivity in the ultimately attained rods.

Method of producing homogeneously doped n-type Si monocrystals by

A homogeneously doped p-conductive semiconductor material is produced by irradiating a desired semiconductor material with .gamma.-photons which trigger nuclear reactions within such irradiated material to form dopant atoms therein.

Method of producing homogeneously doped p-conductive semiconductor

A semiconductor layer, such as an epitaxial layer on a suitable substrate is subjected to controlled bombardment by neutrons whereby the atoms of the semiconductor layer are converted via nuclear reaction into doping material atoms.

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Erlangen, Germany

Ernst W Haas