Abstract: A method for separating isotopes of a compound having molecules in the gaseous state which comprises exciting the gas with laser radiation having a frequency capable of exciting a selected isotope thereof, interacting the excited gas with electrons having an energy sufficient to form position ions therein and separating the ionized molecules from the other molecules in the gas.

Abstract: A circuit arrangement for the automatic de-excitation of a hysteresis motor whose reactive power intake is compensated by capacitors and whose stator windings, which are fed from a three phase mains via a frequency converter, magnetize the rotor with their rotating field and thus produce a permanently magnetic excitation which continues in the rotor in the form of residual magnetic poles even after disconnection of the motor from the three phase mains. A voltage monitor monitors the mains side input to the frequency converter and responds upon interruption of the mains voltage due to malfunction or end of operation. Upon interruption of the mains voltage a capacitor of a buffer circuit in the d.c. intermediate circuit of the frequency converter transfers its stored energy, with decaying voltage, to the stator of the motor via an inverter which forms the output of the frequency converter, and upon response of the voltage monitor, the output frequency f.sub.

Abstract: In a quadrupole mass spectrometer enclosed by a high vacuum container and including an ionization chamber, a molecular beam radiator passing through the container and having an output opening for supplying the gas to be analyzed, and a cryopump arranged for receiving the molecular beam exiting from the output opening and serving as a radiation trap, the output opening of the radiator and the cryopump are disposed at the periphery of the ionization chamber preferably diametrically opposite one another.

Abstract: In a procedure for selectively separating the isotopes of a multi-isotopic element by forming a gas of isotopic compounds of the element, selectively exciting the molecules of one isotopic compound by application of laser radiation thereto, and separating the excited molecules from the other components of the gas by physical or chemical means, the efficiency of the separation is improved by passing the gas, prior to laser excitation, through a nozzle to cause it to undergo adiabatic expansion to form an undercooled gas stream, and applying the laser radiation to the gas stream.

Abstract: A method for controlling the operation of uranium enrichment systems in which gaseous uranium compounds are processed. The method comprises separating at one or a plurality of precipitation points in the system the process uranium gas and/or its secondary products in small quantities, measuring the radioactive radiation of the separated uranium gas and/or its secondary products, identifying the age of the gas passing through the precipitation points by means of the radioactive radiation measurements and then controlling a parameter of the system with the accumulated data of the process gas and its secondary products.