Abstract: A method for a multielement analysis via neutron activation. The method includes generating fast neutrons with an energy in the range of 10 keV to 20 MeV and moderating the neutrons, irradiating the sample with the neutrons, and measuring the gamma radiation emitted by the irradiated sample using a detector to determine at least one element of the sample. The sample continuously irradiated in a non-pulsed fashion. The measurement is implemented during the irradiation. The determination of the at least one element includes an evaluation of the measured gamma radiation. The sample is subdivided into individual partitions and the measurement is implemented using a collimator. The evaluation includes a spatially resolved and energy-resolved determination of the neutron flux within the respective partition of the sample and calculation of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within a single partition of the sample by an approximation method.

Abstract: A method for a multielement analysis via neutron activation. The method includes generating fast neutrons with an energy in the range of 10 keV to 20 MeV and moderating the neutrons, irradiating the sample with the neutrons, and measuring the gamma radiation emitted by the irradiated sample using a detector to determine at least one element of the sample. The sample continuously irradiated in a non-pulsed fashion. The measurement is implemented during the irradiation. The determination of the at least one element includes an evaluation of the measured gamma radiation. The sample is subdivided into individual partitions and the measurement is implemented using a collimator. The evaluation includes a spatially resolved and energy-resolved determination of the neutron flux within the respective partition of the sample and calculation of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within a single partition of the sample by an approximation method.

Abstract: A method for the non-destructive elemental analysis of large-volume samples using neutron radiation and a device for carrying out the method. In the method, the sample is irradiated with fast neutrons in a pulsed manner and the gamma radiation emitted by the sample is measured. The quantity of an element contained in the sample is evaluated after the background signal is subtracted from the area of the photopeak caused by the element in a plot of count rate versus energy. The gamma radiation emitted by a subregion of the sample, the composition of which is known, is evaluated in order to determine the neutron flux at the location of the sample. A metallic enclosure of the sample, such as a standardized waste container, can be selected as such a subregion, for example. A novel evaluation method based on multiparameter analysis can quantify, on the basis thereof, the presence of individual elements more quickly and more accurately than is possible according to the previous prior art.

Abstract: A mixing chamber for an air handling unit having a first inlet, second inlet and an outlet. The first inlet receives a first air stream. The second inlet to receives a second air stream. The outlet discharges a mixed airflow. The first inlet includes a first damper having an opposed blade configuration for controlling the flow of the first air stream and the second inlet includes a second damper having an opposed blade configuration for controlling the flow of the second air stream. The mixing chamber also includes a control arrangement to control operation of the first and second damper. The control arrangement is configured to independently open and close each of the first and second dampers to regulate airflow into the mixing chamber.