Radiation detector with shielding electrode

A cross-strip radiation detector, comprising:

• (a) a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation;
• (b) at least one independent bias electrode formed on a first side of the semiconductor;
• (c) a plurality of signal electrodes formed on a second side of the semiconductor opposing the first side and intercoupled as at least two independent signal strips, each of the signal electrodes maintained at a potential difference with respect to the bias electrode to effect a bias electrical field within the semiconductor;
• (d) a plurality of shield electrodes formed on the second side of the semiconductor and intercoupled as at least one independent shield signal strip to produce an identification signal caused by an ionizing event to determine the location of the ionizing event according to a signal from the signal strips;
• and
• (e) at least one control electrode formed on the second side of the semiconductor relative to the signal electrodes and insulated from the signal electrodes and shield electrodes, the control electrode having a control potential to facilitate collection by the signal electrodes of charge carriers caused by the ionizing radiation.

A cross-strip radiation detector, comprising:

• (a) a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation;
• (b) at least one independent bias electrode formed on a first side of the semiconductor;
• (c) a first electrode layer formed on a second side of the semiconductor opposing the first side, comprising an array of signal electrodes which are intercoupled to form parallel signal strips which are maintained at a potential difference with respect to the bias electrode to effect a bias electrical field within the semiconductor and is operable to produce signals indicative of the ionizing radiation;
• and
• (d) a second electrode layer disposed in proximity of the second side of the semiconductor and capacitively coupled to the semiconductor, the second electrode layer having a plurality of independent parallel shield electrode strips that are insulated from and not parallel to the signal strips, wherein the shield electrode strips are operable to produce identification signals caused by an ionizing event to determine the location of the ionizing event according to signals from the signal strips caused by the ionizing event.

A radiation imaging device, comprising a plurality of cross-strip detector elements arranged relative to one another side-by-side to form a detector array, each cross-strip detector element comprising:

• (1) a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation;
• (2) at least one independent bias electrode formed on a first side of the semiconductor;
• (3) a first electrode layer formed on a second side of the semiconductor opposing the first side, comprising an array of signal electrodes which are intercoupled to form parallel signal strips which are maintained at a potential difference with respect to the bias electrode to effect a bias electrical field within the semiconductor and are operable to produce signals indicative of the ionizing radiation;
• (4) an insulation layer formed on the first electrode layer on the second side of the semiconductor;
• (5) a second electrode layer formed over the insulator layer and capacitively coupled to the semiconductor, the second electrode layer having a plurality of independent parallel shield electrode strips that are insulated from and not parallel to the signal strips, wherein the shield electrode strips are operable to produce identification signals caused by an ionizing event to determine the location of the ionizing event according to signals from the signal strips caused by the ionizing event.

A method of forming a cross-strip radiation detector, comprising:

• (a) providing a semiconductor which has a plurality of sides and of sufficient thickness to interact with ionizing radiation;
• (b) forming at least one independent bias electrode on a first side of the semiconductor;
• (c) forming a first electrode layer on a second side of the semiconductor opposing the first side, the first electrode layer having an array of signal electrodes which are coupled to form parallel signal strips;
• (d) forming a second electrode layer on the second side which has a plurality of independent parallel shield electrode strips, that are insulated from and not parallel to the signal strips, to shield the signal electrodes from trapped charge;
• and
• (e) applying a bias electrical field within the semiconductor between the bias electrode on the first surface and the signal electrodes on the second surface to produce a first set of signals from the signal electrodes and a second set of signals from the shield electrode strips;
• (f) processing one of the first set of signals to determine an amount of the charge produced in the semiconductor by the ionizing event, without reference to the second set of signals;
• and
• (g) using the first and second set of signals to respectively determine a first position along a direction perpendicular to the signal strips and a second position along a direction perpendicular to the shield electrode strips so as to determine a location of the ionizing event in the semiconductor.

A radiation detector, comprising:

• (a) a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation;
• (b) at least one independent bias electrode formed on at least two adjacent sides of the semiconductor;
• (c) a signal electrode formed on a signal side of the semiconductor that is not covered by the bias electrode, wherein the signal electrode is electrically insulated from the bias electrode and is maintained at a bias potential with respect to the bias electrode to effect a bias electrical field within the semiconductor so that the signal electrode is operable to produce signals indicative of the ionizing radiation;
• and
• (d) a shield electrode disposed in proximity of the signal side of the semiconductor and capacitively coupled to the semiconductor, wherein the shield electrode is insulated from the semiconductor, the bias and signal electrodes and operable to reduce the induced charge on the signal electrode.