Apparatus and method for adjusting a collimator

• US 6,483,894 B2
• Filed: 01/16/2001
• Issued: 11/19/2002
• Est. Priority Date: 11/13/1999
• Status: Expired due to Term

• Current Assignee: Smiths Heimann GmbH
• Original Assignee: Heimann Systems GmbH
• Inventors: Hartick, Martin, Cordes, Frank
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): Hobden, Pamela R.
• Application Number:
  US09/759,643
• Publication Number:
  US 20010036250A1
• Time in Patent Office: 672 Days
• Field of Search: 378/147, 378/145, 378/16, 250/515.1, 250/505.1
• US Class Current: 378/147
• CPC Class Codes: G01N 23/20 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
• CPC Class Codes: G01V 5/22 Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
• CPC Class Codes: G01V 5/222 measuring scattered radiation
• CPC Class Codes: G01V 5/224 Multiple energy techniques using one type of radiation, e.g. X-rays of different energies
• CPC Class Codes: G21K 5/04 with beam-forming means

Abstract

A collimator for an X-ray testing machine and a method for adjusting the collimator with the aid of a detection system disposed in the collimator that includes at least two spatially separate detection devices, disposed and spacing one behind the other.

Claims

1. An X-ray testing machine comprising:

an X-ray source for generating X-ray radiation;

elements for generating a primary beam of the x-ray radiation;

a collimator for the x-ray radiation;

means for orienting the collimator relative to the primary beam including a central, blind-bore opening in said collimator; and

first and second detection devices disposed and spaced one behind the other inside the central opening.

2. The apparatus according to claim 1, wherein a collimator arrangement is mounted in front of the first detection device.

3. The apparatus according to claim 2, wherein a collimator arrangement is mounted in front of the second detection device.

4. The apparatus according to claim 1, wherein the collimator is a ring-slot collimator having a conically-expanding round slot that is spaced from the central opening, said slot determining an angular path of a predetermined angle.

5. The apparatus according to claim 4, wherein a detector is fixedly associated with the collimator and possesses an X-ray-sensitive surface that faces the collimator, said detector being oriented such that scattering-cone beams exiting the slot are received by said detector.

6. The apparatus according to claim 1, wherein at least one of the first and second detection devices comprise a four-quadrant detector.

7. The apparatus according to claim 1, wherein at least one of the first and second detection devices comprise at least two individual detectors.

8. The apparatus according to claim 1, wherein at least one of the first and second detection devices are constructed from position-sensitive detectors having multiple-segmented diodes.

9. The apparatus according to claim 1, wherein at least one of the first and second detection devices comprise a detector array.

10. The apparatus according to claim 1, wherein the first detection device, which is disposed closer to the x-ray source, detects relatively lower energy X-rays, and the second detection device detects relatively higher energy X-rays.

11. The apparatus according to claim 1, further comprising a first amplifier stage electrically connected to the first detection device;

a second amplifier stage electrically connected to the second detection device; and

a central microprocessor connected downstream of the first and second amplifier stages.

12. A method for adjusting a collimator in an X-ray testing machine relative to a primary X-ray beam comprising:

providing first and second X-ray detection devices, which are spatially separated, disposed and spaced one behind the other along the primary beam; and

, using the signal from the first and second detection devices to spatially orient the collimator so that the primary beam impacts the centers of the first and second detection devices at a right angle by;

in a first step, moving the collimator until a signal at the first detection device is maximal; and

in a second step, rotating the collimator in two independent planes about a point in a first rotational plane until a signal from the second detection device is maximal.

13. The method according to claim 12, further comprising using a microprocessor to evaluate the signals from the first and second detection devices and to determine the position of the intensity maximum in the rotation plane, with the individual signals being evaluated to directly determine the offset between a primary-beam center and detection centers of the first and second detection devices, which must then be readjusted.