Atom Sciences, Inc.

Consultec Scientific, Inc.

The United States of America As Represented by the United States Energy

Pellissippi International

George S Hurst

Harvel A Wright

Norbert Thonnard

Marvin G Payne

Scott Robert Hunter

Philip Karl Hopke

James E Turner

Steve L Allman

Robert N Hamm

Edward B Wagner

A system for determining the health risk, due to alpha emitters attached to particles of various sizes, these alpha emitters being due to the level of radon, to persons within an environment where radon may be present. In one embodiment, a sample of air is passed through a filter element having a collection characteristic such that essentially all particulate material, with their associated radon progeny, is removed from the air. The alpha particles emitted by the decay of these radon progeny are detected with an appropriate alpha particle spectrometer. The realtime resolving of the energies of individual of the daughter atoms permits a determination of the working level or PAEC associated with the radon. In those instances where lung dose is to be determined, the filter element has two portions. The first portion is designed to remove particles in a manner like that which occurs in the human nasal passage. The second portion of the filter element is designed to simulate the collection of particles by the lungs. An analysis of the energies of the alphas emitted from the radon progeny collected on the second portion is used to compute the lung dose. Either of the embodiments can be used to provide a signal that would be used for the operation of any radon mitigation equipment associated with the environment. Other uses for the resultant signals are discussed.

System for determining health risk due to radon progeny and uses thereof

A system for monitoring or controlling the level of radon in indoor air, based upon measuring alpha particles due to the decay of radon or its daughter atoms. In one embodiment, the alpha particle decay of radon itself is detected and analyzed to control a vent in the heating and air conditioning system to automatically keep the radon level below a preselected level. In another embodiment, the daughter atoms .sup.218 Po and .sup.214 Po are collected from the indoor air and their alpha particle decays are analyzed to provide a sensitive monitor of radon levels or to control vents in the HVAC system to reduce radon concentrations to permissible levels. In addition, the system provides information on the quality of the air filter and indicates when it needs servicing.

Radon monitor and control system based upon alpha particle detection

An optical ionizing radiation detector system (10) for determining the three-dimensional spatial distribution of all of the secondary electrons produced by the passage of ionizing radiation through a selected gas is provided. The detector system (10) can be used over a wide range of particle energies and gas pressures. The ionizing radiation passing through the gas produces prompt fluorescence and secondary electrons. A coincidence detector (30) recognizes coincident events of prompt fluorescence in the gas contained within that chamber to initialize the system cycle. At that time, an AC electric field is generated by an R.F. pulse generator (40) to localize the secondary electrons proximate their respective positions of production. Cameras (42) and 42'), preferably of a digital type, produce an image of the localized electrons to determine their three-dimensional spatial positions. After such positions are determined, a unidirectional electric field is generated by clearing power supply (36) for clearing all charges from the gas chamber.

Ionizing radiation detector system

An improved method of operating a time-of-flight mass spectrometer. This method, which involves double pulsing, achieves an increase in the resolution of TOF mass spectrometers by compensating for the energy spread of the species extracted from the source and thus the time spread of ions of a specific mass arriving at a detector. According to this improved method, atoms (or molecules) for analysis are rapidly removed from a surface at a first well defined time. These atoms or molecules are then rapidly ionized at a location or region a distance, R, from the surface at a second well defined time after a selected time delay, T.sub.o. The resultant ions first move through a region of uniform electric field of a distance, S.sub.1, and then into a field-free region having a length, S.sub.2, Lastly, ions leaving the field-free region enter a short high energy accelerating region so as to impinge upon an ion detector. The output signal of the detector, as a function of arrival time, is an indication of the mass distribution of the ions and thus the analysis of the atoms or molecules. A proper choice of the uniform electric field and parameters R, S.sub. 1, S.sub.2 and T.sub.o provide compensation for the energy spread of ionized species and thus a reduction in time spread of ions at the detector. Certain special cases for enhanced resolution are described, as well as operation of the TOF according to the improved method to achieve atom enrichment of a specific mass.

Double pulsed time-of-flight mass spectrometer

Method and apparatus for determining small quantities of specific atoms with isotopic selectivity. According to the method described herein, atoms are rapidly released from an atom bank containing the same, and are then converted to ions utilizing resonance ionization as achieved with photon beams having specific wave lengths. These ions are extracted from the ionization region and are accelerated and implanted into a second atom bank. For further selectivity, the atoms are then rapidly released from the second bank, ionized with another photon beam of selected wave length to provide ionization of the desired species, with these ions then being extracted, subjected to acceleration, and implanted into the first atom bank. Typically the number of electrons emitted from the atom banks during implantation is used as a measure of the number of atoms of the selected species. In the preferred embodiments, a combination of mass selectivity by ionization together with a mass separator provides for the most rapid and most sensitive method for determining a small quantity of atoms in the presence of a large quantity of atoms.

Method and apparatus for sensitive atom counting with high isotopic

This invention relates to a method for the sensitive and selective analysis of an atomic or molecular component of a gas. According to this method, the desired neutral component is ionized by one or more resonance photon absorptions, and the resultant ions are measured in a sensitive counter. Numerous energy pathways are described for accomplishing the ionization including the use of one or two tunable pulsed dye lasers.

Growing community of inventors

Oak Ridge, TN, United States of America

George S Hurst