DIRECT CONVERSION X-RAY DETECTOR WITH RADIATION PROTECTION FOR ELECTRONICS

• US 20130026379A1
• Filed: 07/27/2012
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Lohse, Thomas, Krueger, Peter, Oppermann, Martin, Zerna, Thomas, Albrecht, Oliver, Metasch, Ren, Oettl, Annika
• Granted Patent: US 8,963,098 B2
• Time in Patent Office: Days
• US Class Current: 250/370.12
• CPC Class Codes: G01T 1/24 with semiconductor detectors
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48111 the wire connector extending above another semiconductor or solid-state body
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/73257 Bump and wire connectors
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14661 of the hybrid type
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H04N 23/30 for generating image signals from X-rays
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

The present invention relates to an X-ray detector having an X-ray sensor (first X-ray sensor) converting X-radiation directly into electric charge carriers, having signal evaluation electronics electrically connected to the X-ray sensor and preferably formed as integrated circuit(s), having an X-ray absorber formed for protecting the signal evaluation electronics, and having a sensor carrier (first sensor carrier) formed and arranged for positioning the X-ray sensor relative to the X-ray absorber, wherein, viewed in the direction of incidence of the X-radiation, both the signal evaluation electronics are arranged behind the X-ray absorber and in the X-radiation shadow thereof and the X-ray sensor is admittedly likewise positioned by means of the sensor carrier preferably arranged between the X-ray absorber and the signal evaluation electronics at least sectionally behind the X-ray absorber, but outside the X-radiation shadow thereof.

Claims

1. An X-ray detector comprising

a first X-ray sensor directly converting X-radiation (R) into electric charge carriers;

signal evaluation electronics electrically connected to the X-ray sensor and including an integrated circuit;

an X-ray absorber, configured to protect the signal evaluation electronics; and

a sensor carrier configured and arranged for positioning the X-ray sensor relative to the X-ray absorber,

wherein, viewed in the direction of incidence of the X-radiation, both the signal evaluation electronics are arranged behind the X-ray absorber and in the X-radiation shadow (S) thereof and the X-ray sensor is likewise situated such that the sensor carrier is arranged between the X-ray absorber and the signal evaluation electronics at least sectionally behind the X-ray absorber, but outside the X-radiation shadow (S) thereof.

2. The X-ray detector of claim 1, wherein the X-ray absorber, the sensor carrier and the signal evaluation electronics are arranged together on a substrate, in particular a circuit board, in the aforesaid order viewed in the direction of incidence (E) of the X-radiation (R);

wherein the material of the sensor carrier arranged in the direction (x), viewed perpendicular to this direction of incidence (E) and perpendicular to the plane (y, z) of the substrate, between the substrate and the X-ray sensor has a thermal coefficient of expansion which lies between the thermal coefficient of expansion of the material of the substrate and that of the material of the X-ray sensor and/or adapts the thermal expansion of the X-ray sensor to that of the substrate; and

/or

wherein, viewed perpendicular to the direction of incidence (E) of the X-radiation (R) and perpendicular to the plane (y, z) of the substrate, the sensor carrier has the same extent as the X-ray absorber and/or is positioned completely in the X-radiation shadow (S) of the X-ray absorber.

3. The X-ray detector of claim 1, comprising a further second X-ray sensor that converts the X-radiation (R) directly into electric charge carriers and that is likewise electrically connected to the signal evaluation electronics;

and

a further second sensor carrier configured and arranged for positioning the second X-ray sensor relative to the X-ray absorber,

wherein, viewed in the direction of incidence (E) of the X-radiation (R), the second X-ray sensor is arranged behind the first X-ray sensor and is likewise situated such that the second sensor carrier is arranged between the first sensor carrier and the signal evaluation electronics behind the X-ray absorber, but outside the X-radiation shadow (S) thereof.

4. The X-ray detector in accordance with claim 3, wherein the second sensor carrier has the same extent as the X-ray absorber viewed perpendicular to the direction of incidence (E) of the X-radiation (R) and perpendicular to the plane (y, z) of the substrate;

and/or

wherein the first sensor earlier and/or the second sensor carrier is/are completely positioned in the X-radiation shadow (S) of the X-ray absorber; and

/or

wherein the material of the second sensor carrier arranged, viewed in the direction (x) perpendicular to this direction of incidence (E) and perpendicular to the plane (y, z) of the substrate, between the substrate and the second X-ray sensor has a thermal coefficient of expansion that lies between the thermal coefficient of expansion of the material of the substrate and that of the material of the second X-ray sensor and/or that adapts the thermal expansion of the second X-ray sensor to that of the substrate.

5. The X-ray detector of claim 1, wherein the first sensor carrier and/or the second sensor carrier is/are configured as electrically conductive and for the electric voltage supply of the first X-ray sensor and/or of the second X-ray sensor.

8. The X-ray detector of claim 3, wherein the two X-ray sensors are configured for absorbing different spectral portions of the X-radiation (R), with the first X-ray sensor being configured for absorbing a lower energy portion of the X-ray radiation (R) and the second X-ray sensor being configured for absorbing a higher energy portion of the X-radiation (R) and/or containing semiconductor materials of different atomic numbers;

and/or

wherein one of the two X-rav sensors contains Si and the other of the two X-ray sensors contains GaAs.

9. The X-ray detector of claim 1, comprising a beam stop provided with an opening, wherein the beam stop, viewed in the direction of incidence (E) of the X-radiation (R), is arranged before the first X-ray sensor or before the first X-ray sensor and the second X-ray sensor and that is aligned such that the first X-ray sensor or the first and the second X-ray sensor is/are not arranged in the X-radiation shadow (SB) of the wall of the beam stop, but rather behind the opening.

10. The X-ray detector of claim 1, wherein the first X-ray sensor and/or the second X-ray sensor, include a plurality of individual pixels viewed in a direction (z) perpendicular to a direction of incidence (E) of the X-radiation (R) and in the plane (y, z) of the substrate for the spatially resolved detection of the X-radiation (R), said individual pixels being electrically connected to the signal evaluation electronics for transmitting sensor signals to the signal evaluation electronics via bond wires and/or via flip-chip contacts.

11. The X-ray detector of claim 10, wherein both X-ray sensors have such a line sensor structure and are positioned after each other viewed in the direction of incidence (E) of the X-radiation (R) such that pixels of the first X-ray sensor projected in parallel in this direction of incidence (E) come to lie exactly on pixels of the second X-ray sensor so that identical spatial information is capable of being acquired with the two X-ray sensors.

12. The X-ray detector of claim 1, wherein the first X-ray sensor and the second X-ray sensor are configured to be supplied with electric voltage separately and independently of each other.

13. The X-ray detector of claim 11, configured in a plurality of the X-ray detectors that are stacked over one another with their substrate planes lying in parallel such that the line sensor structures of their first X-ray sensors or their first and second X-ray sensors in the plane (x, z) viewed perpendicular to the direction of incidence (E) of the X-radiation (R) form (a) two-dimensional area sensor structure(s) in the form of (a) two-dimensional pixel array(s).

6. An X-ray detector comprising

a substrate;

a first X-ray sensor and a second X-ray sensor that both respectively convert X-radiation (R) directly into electric charge carriers and that are both arranged on a first side of the substrate;

signal evaluation electronics that are electrically connected to both X-ray sensors, that include or are formed as one or more integrated circuits and that are arranged on the second side of the substrate disposed opposite the first side; and

an X-ray absorber that is formed for the protection of the signal evaluation electronics, that is arranged on the second side of the substrate in front of the signal evaluation electronics viewed in the direction of incidence (E) of the X-radiation (R) and that is positioned such that the signal evaluation electronics are arranged in the X-radiation shadow (S) of the X-ray absorber.

7. The X-ray detector of claim 6, wherein the electrical connection of the signal evaluation electronics to the first X-ray sensor and/or to the second X-ray sensor serving the transmission of the sensor signals to the signal evaluation electronics is configured using one or more electrically conductive vias leading through the substrate.