| 摘要 |
<p>Directional probe has at least five small Geiger-Muller counters held symmetrically within and parallel to the axis of a collimator. The resistance connected to the cathodes are protected by a head shield, and with a preamplifier of anode current all parts are in a metal casing. Pref. the collimator consists of alternating rings of lead and an absorbant plastic material; and in one form, is held between lead end walls at least five times thicker than the rings one having an oblique passage for cable connection. Casing consists of a light alloy tube, closed by a soft stopper of light alloy.</p> |
