| 摘要 |
<p>A radiation detector (50) includes a substrate (52) having a cavity (56), an anode surface (68a) positioned at the bottom and a cathode (72) positioned adjacent the cavity opening. A drift electrode (80) is juxtaposed over the substrate opposite the cavity and defines a region (82) containing a gaseous medium (84). As ionized charged pairs (98, 100) are established in the gaseous medium due to an external radiation source (90), electrons drift toward the anode under the influence of a first electric field between the anode and drift electrode. Thereafter, the electron undergoes avalanche multiplication with the gaseous medium in an avalanche region defined by a second intense electric field between the anode and cathode. The present invention provides an electric field gradient geometry which permits optimal design of the avalanche region geometry, and which further minimizes photon feedback from the cathode.</p> |
