| 摘要 |
<p>A method and counter for reducing the background counting rate in gas-filled alpha particle counters (Fig.10) wherein the counter is constructed in such a manner as to exaggerate the differences in the features in preamplifier (11 and 111) pulses generated by collecting the charges in ionization tracks (23) produced by alpha particles emanating from different regions within the counter (50) and then using pulse feature analysis to recognize these differences and so discriminate between different regions of emanation (6). Thus alpha particles emitted from the sample can then be counted while those emitted from the counter components can be rejected, resulting in very low background counting rates even from large samples. A guard electrode (33) can be placed about the anode's perimeter (205, 200) and secondary pulse feature analysis performed on signal pulses output from a preamplifier (11) attached to this guard electrode to further identify and reject alpha particles emanating from the counter's sidewalls (26) in order to further lower the counter's background.</p> |
