Semiconductor radiation detector with enhanced charge collection

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 bias electrode formed on at least one side of the semiconductor;
• (c) at least one signal electrode formed on at least one side of the semiconductor;
• (d) at least one focus control electrode, formed on at least one side of the semiconductor and having a first potential, for directing charge clouds resulting from ionizing events in the semiconductor towards an associated signal electrode;
• and
• (e) at least one shield control electrode, formed on at least one side of the semiconductor near the signal electrode and having a second potential, for reducing the effect on an associated signal electrode of charge induced by trapped charges in the semiconductor;
• and
• (f) at least one supplemental shielding control electrode, formed on at least one side of the semiconductor and having a third potential, for reducing the effect on an associated signal electrode of charge induced by trapped charges in the semiconductor.

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 parallel strip bias electrode formed on at least one side of the semiconductor;
• (c) a plurality of signal electrodes formed on at least one side of the semiconductor and intercoupled as at least two independent signal strips effectively orthogonal to the parallel strip bias electrodes, each signal strip including one or more electrically coupled signal electrodes;
• and
• (d) at least one control electrode, formed on at least one side of the semiconductor, for performing at least one of the functions of (A) directing charge clouds resulting from ionizing events in the semiconductor towards the signal electrode and (B) substantially reducing the effect on the signal electrode of hole trapping in the semiconductor.

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 bias electrode formed on at least one side of the semiconductor;
• (c) a plurality of signal electrodes formed on at least one side of the semiconductor and intercoupled as at least two independent signal strips, each signal strip including one or more electrically coupled signal electrodes;
• and
• (d) a plurality of independent parallel strip control electrodes, formed on at least one side of the semiconductor near the signal electrodes and effectively orthogonal to the signal strips, for performing at least one of the functions of (A) directing charge clouds resulting from ionizing events in the semiconductor towards the signal electrode and (B) substantially reducing the effect on the signal electrode of hole trapping in the semiconductor.

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 parallel strip bias electrode formed on at least one side of the semiconductor;
• (c) a plurality of independent parallel strip signal electrodes formed on at least one side of the semiconductor effectively orthogonal to the parallel strip bias electrodes;
• and
• (d) a plurality of parallel strip control electrodes, formed on at least one side of the semiconductor near and interdigitated with the parallel strip signal electrodes, for performing at least one of the functions of (A) directing charge clouds resulting from ionizing events in the semiconductor towards the signal electrode and (B) substantially reducing the effect on the signal electrode of hole trapping 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 bias electrode formed on at least one side of the semiconductor;
• (c) a plurality of signal electrodes formed on at least one side of the semiconductor and interconnected as at least two independent signal elements, each signal element including one or more electrically coupled signal electrodes;
• and
• (d) at least one control electrode, formed on at least one side of the semiconductor near the signal electrodes, for directing charge clouds resulting from ionizing events in the semiconductor towards the signal electrodes and for substantially reducing the effect on the signal electrodes of hole trapping in the semiconductor.

A radiation detector, comprising:

• (a) a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation, the semiconductor having a radiation illumination surface;
• (b) at least one bias electrode formed on at least one side of the semiconductor orthogonal to the illumination surface;
• (c) at least one signal electrode formed on at least one side of the semiconductor orthogonal to the illumination surface;
• and
• (d) at least one control electrode, formed on at least one side of the semiconductor, for performing at least one of the functions of (A) directing charge clouds resulting from ionizing events in the semiconductor towards the signal electrode and (B) substantially reducing the effect on the signal electrode of hole trapping in the semiconductor.

An ionization chamber, comprising:

• (a) a chamber enclosing a radiation interaction material comprising one of a liquid or a gas, the chamber having a plurality of sides;
• (b) at least one bias electrode formed on at least one side of the chamber;
• (c) at least one a signal electrode formed on at least one side of the chamber;
• and
• (d) at least one control electrode, formed on at least one side of the chamber, for directing charge resulting from ionizing events in the radiation interaction material towards the signal electrode and for substantially reducing the effect on the signal electrode of non-collected ions of an opposite polarity to such charge.

A method for determining timing information for a radiation detector having a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation;

• at least one bias electrode formed on at least one side of the semiconductor;
• at least one signal electrode formed on at least one side of the semiconductor;
• and at least one control electrode, formed on at least one side of the semiconductor for performing at least one of the functions of (A) directing charge clouds resulting from ionizing events in the semiconductor towards at least one signal electrode and (B) substantially reducing the effect on at least one signal electrode of hole trapping in the semiconductor, the method including the steps of:
• (a) determining a first time measurement indicating when a signal measured from at least one of the bias electrodes or the control electrodes exceeds a first selected threshold;
• (b) determining a second time measurement indicating when a signal on at least one signal electrode exceeds a second selected threshold;
• (c) determining the difference between the first time measurement and the second time measurement.

A method for determining depth of interaction of an ionizing event in a radiation detector having a semiconductor having a plurality of sides and of sufficient thickness to interact with ionizing radiation;

• at least one bias electrode formed on at least one side of the semiconductor;
• at least one signal electrode formed on at least one side of the semiconductor;
• and at least one control electrode, formed on at least one side of the semiconductor for performing at least one of the functions of (A) directing charge clouds resulting from ionizing events in the semiconductor towards at least one signal electrode and (B) substantially reducing the effect on at least one signal electrode of hole trapping in the semiconductor, the method including the steps of:
• (a) measuring a magnitude of charge signal, resulting from ionizing events in the semiconductor, on at least one of the bias electrodes, the control electrodes, or the signal electrodes;
• and
• (b) determining a relationship between depth of interaction of the ionizing event and a combination of the magnitudes of the measured charge signals.