DIRECT CONVERSION PHOTON COUNTING DETECTOR

• US 20150234058A1
• Filed: 09/18/2013
• Published: 08/20/2015
• Est. Priority Date: 09/18/2012
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Philips Deutschland GmbH (Koninklijke Philips N.V.)
• Inventors: Engel, Klaus Juergen, Steadman Booker, Roger, Herrmann, Christoph
• Granted Patent: US 9,535,174 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01T 1/241 Electrode arrangements, e.g. continuous or parallel strips or the like constructional or manufacturing details H01L31/00
• CPC Class Codes: G01T 1/249 specially adapted for use in SPECT or PET SPECT imaging G01T1/1642; PET imaging G01T1/2985; detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects G01V5/20

Abstract

The present invention discloses a pixilated direct conversion photon counting detector with a direct conversion material layer and a pixilated electrode. Individual electrode pixels are segmented into three segments (510, 520, 530), wherein one of the segments (520) is operated at a more electrically repellant value than that of the other two (510, 530). Said other two segments are connected to electric circuitry (610, 611, 620, 630) that is arranged to generate signals which are indicative of a count of electrons or holes that approach each of the respective electrode pixel segments and to subtract the generated signals from each other.

Claims

1. A direct conversion photon counting detector, comprising a detector cathode, a detector anode and a direct conversion material layer positioned between said detector cathode and said detector anode, said detector anode and/or detector cathode comprising a plurality of electrode pixels that are adapted to detect a presence of electrons or holes,

wherein at least one of the electrode pixels is segmented into at least a first electrode pixel segment, a second electrode pixel segment and a third electrode pixel segment;

wherein an electrical potential of the third electrode pixel segment is at a more electrically repellant value than an electrical potential of the first electrode pixel segment and than an electrical potential of the second electrode pixel segment;

wherein the detector further comprises electronic circuitry electrically coupled to the first electrode segment and to the second electrode segment to generate a first electrical signal and a second electrical signal respectively, said electronic circuitry comprising a signal subtractor configured to subtract the second electrical signal from the first electrical signal.

2. A detector according to claim 1 wherein said electronic circuitry further comprises at least one electrical signal amplifier.

3. A detector according to claim 1, wherein the first electrode pixel segment is spatially separated from the third electrode pixel segment by at least the second electrode pixel segment.

4. A detector according to claim 1, wherein at least one of the first electrode pixel segment, second electrode pixel segment or third electrode pixel segment is sub-segmented into at least two electrode pixel sub segments.

5. A detector according to claim 1, wherein the third electrode pixel segment extends continuously over at least two neighboring electrode pixels.

6. A detector according to claim 1, wherein the second electrode pixel segment surrounds the first electrode pixel segment and the third electrode pixel segment surrounds the second electrode pixel segment.

7. A detector according to any of the claim 1, wherein the first electrode pixel segment extends from one side of the electrode pixel to an opposite side of the electrode pixel.

8. A detector according to claim 1, wherein an area covered by the first electrode pixel segment is approximately equal to a total area covered by the second electrode pixel segment.

9. A detector according to claim 1, wherein the second electrode pixel segment has a width of at least 50 microns.

10. A detector according to claim 1, wherein the electrical potential of the first electrode pixel segment approximately matches the electrical potential of the second electrode pixel, preferably the electrical potential of the first electrode pixel segment and the electrical potential of the second electrode pixel are at ground potential.

11. A detector according to claim 1, wherein a difference between a first electrode electric potential and a third electrode pixel segment electric potential is between 100 and 200 volts.

12. A detector according to claim 1, wherein a difference between a detector cathode electric potential and the third electrode pixel segment electric potential is between 100 and 500 volts per millimeter thickness of the direct conversion layer.

13. An imaging system, preferably a computed tomography system, comprising a detector according to claim 1.

14. A method to detect photons with a direct conversion photon counting detector, comprising a detector cathode, a detector anode and a direct conversion material layer positioned between said detector cathode and said detector anode, said detector anode and/or detector cathode comprising a plurality of electrode pixels that are adapted to detect a presence of electrons or holes, wherein at least one of the electrode pixels is segmented into at least a first electrode pixel segment, a second electrode pixel segment and a third electrode pixel segment;

wherein the detector further comprises electronic circuitry electrically coupled to the first electrode segment and to the second electrode segment, said electronic circuitry comprising a signal subtractor configured to subtract the second electrical signal from the first electrical signal;

said method comprising the steps of;

applying an electrical potential to the detector cathode and to each of the pixel segments, wherein the third electrode pixel segment is operated at a more electrically repellant electrical potential than the first electrode pixel segment and the second electrode pixel segment;

irradiating the direct conversion material with photons to generate electrons and holes;

generating a first electrical signal which is indicative of a count of electrons or holes that approached the first electrode pixel segment;

generating a second electrical signal which is indicative of a count of electrons or holes that approached the second electrode pixel segment;

generate a corrected signal by subtracting the second electrical signal from the first electrical signal; and

processing the corrected signal to generate detection data.

15. A method according to claim 14, comprising the further step of:

amplifying the first electrical signal and the second electrical signal.