عنوان مقاله [English]
نویسندگان [English]چکیده [English]
One of the important goalsin chemical agent detection is to construct an instrument with a fast response, to be handled easily, and to be used in various operational conditions. In this paper, based on the phenomenon of “increasing the specific alpha particles ionization rate by decreasing the particles energy” a suggestion has been made for reducing the size of the ionization chamber of an IMS detection system, where a thin layer was placed on the surface of Am-241 ionizing source for decreasing the emitted alpha particles energy. With this method, to some extent, the rate of ionization loss has been compensated. The effect of layer over the Am-241 source on the ionization rate has been predicted theoretically, as well. For the other two sources with the initial coated layers, a calculation has been performed with the use of the related energy distribution; and the effect of a layer, of the Mylar type, on the ionization rate has also been investigated. The results of both cases have shown that the layer will cause to increase the ionization rate in the ionization chamber, where it subsequently increases the capability of the instrument, and the system resolution power for detecting various chemical agents.