Abstract: A reflector to reflect solar radiation, the reflector having a concave reflector surface, wherein the surface curves about a first axis and a second axis, the second axis being in a plane generally normal to the first axis and curved about the first axis. Also disclosed is an apparatus for collection and utilization of solar energy including at least one of the reflectors, and at least one photovoltaic cell associated with each surface and positioned relative to the associated surface so as to be positioned to receive radiation reflected by the associated surface and to convert the radiation to electrical energy. The apparatus further includes heat a conversion mechanism for converting excess solar radiation energy incident thereon to heat energy.

Abstract: A method of determining the distance, from a reference point, of a tracer emitting radiation comprising a first component emitted at a first known energy level and a second component emitted at a second known energy level, the intensity of a penetrating portion of the first component that penetrates a substance between the tracer and the reference point and the intensity of a penetrating portion of the second component of the radiation that penetrates the substance being a function of the rate of gamma radiation emission of the tracer as well as of the distance of the tracer from the reference point, the method comprising: a) measuring the intensity of the first penetrating portion and the intensity of the second penetrating portion; b) determining the ratio of the intensity of the first penetrating portion to the intensity of the second penetrating portion; and c) determining the distance of the tracer from the reference point.

Abstract: The present invention relates to a method for determining at least one ratio of different isotopes of at least one element in a sample. The method comprises ionizing the sample to produce ions of the different isotopes of the at least one element, the ions being selected from the group consisting of: multiply charged atomic positive ions, single charged positive ions for hydrogen and single charged positive ions for deuterium, separating the charged positive ions of the different isotopes of the at least one element according to their mass-to-charge ratios, and determining at least one ratio of the different isotopes of said at least one element separated in the previous step. The invention also relates to an apparatus for performing the above method.