Method for determining the material composition of a material sample

1. A method for determining the presence of a material composition in a material sample, said material sample emitting radiation, comprising:

recording a spectrum of the energy deposited in a detector material by the emitted radiation;

determining a first deposited energy as an integral of the recorded energy deposited over a first energy range extending from a first energy to a second energy, determining a second deposited energy as an integral of the recorded energy deposited over a second energy range extending from the second energy to a third energy, and determining a third deposited energy as an integral of the recorded energy deposited over a third energy range;

assigning a first colour parameter to the first deposited energy, a second colour parameter to the second deposited energy, and a third colour parameter to the third deposited energy;

determining a colour vector from the first colour parameter, the second colour parameter and the third colour parameter; and

comparing the colour vector with a volume in a three-dimensional colour parameter space associated with a predetermined material composition so as to determine if the material sample includes the predetermined material composition.

2. The method according to claim 1 , further comprising:

determining energies deposited in further energy ranges, and

assigning further colour parameters to said further energies.

3. The method according to claim 1 , wherein exactly three deposited energies and exactly three colour parameters are detected.

4. The method according to claim 1 , further comprising:

detecting the emitted radiation with a detector element, said detector element comprising a detector material, and

selecting a distance between said energy ranges as a function of an energy resolution of said detector element.

5. The method according to claim 4 , wherein recording the spectrum comprises measuring a distribution of events in which energy is deposited in the detector material as a function of the energy deposited.

6. The method according to claim 1 , further comprising: irradiating neutrons on the material sample to activate the material sample.

7. The method according to claim 1 , further comprising:

detecting the emitted radiation with an angular resolution with a detector assembly, said detector assembly comprising at least one detector element having a front face and a rear face, wherein:

a space between the front face and the rear face of the detector element is Filled with a plurality of regions of a first detector material and at least one region of a second detector material, and each region connects the front face to the rear face of the detector element; and

wherein an energy deposition takes place in at least the regions of the first detector material as a function of an angle of incidence of the emitted radiation on the detector element; and

determining a preferred angle of rotation, for which the energy deposited in the first and/or second energy region is a maximum or a minimum.

8. The method according to claim 7 , comprising:

determining a direction of a radiation source relative to the detector element as a function of the preferred angle of rotation.

9. The method according to either claim 7 , further comprising:

determining a direction parameter as a function of the ratio of the first and second deposited energies.

10. The method according to claim 9 , further comprising:

determining the direction parameter r for various detection directions, the respective detection direction being substantially normal to the front face of the detector element.

11. The method according to either claim 9 , further comprising:

determining a direction of the radiation source relative to the detector element as a function of the direction parameter r.

12. The method according to claim 7 , wherein in which the first and second regions of said at least one detector clement comprise active and separately readable detector material, the method further comprising: adding the energies determined for the first, second and third energy ranges and deposited in the first and second detector materials.

13. A detector assembly for the detection of radiation emitted by a material sample, comprising:

at least one detector element comprising an active detector material;

a detection device being coupled to the detector element and receiving signals from the detector element; and

an evaluation device which detects a distribution of energies deposited in the detector material as a function of the signals, said evaluation device being operable to a least perform the steps of:

recording a spectrum of the energy deposited in the active detector material by the emitted radiation;

determining a first deposited energy as an integral of the recorded energy deposited over a first energy range extending from a first energy to a second energy, determining a second deposited energy as an integral of the recorded energy deposited over a second energy range extending from the second energy to a third energy, and determining a third deposited energy as an integral of the recorded energy deposited over a third energy range;

assigning a first colour parameter to the first deposited energy, a second colour parameter to the second deposited energy, and a third colour parameter to the third deposited energy;

determining a colour vector from the first colour parameter, the second colour parameter and the third colour parameter; and

comparing the colour vector with a volume in a three-dimensional colour parameter space associated with a predetermined material composition so as to determine if the material sample includes the predetermined material composition.

14. The detector assembly according to claim 13 , wherein the detection device is configured as a light measurement device, which integrally detects scintillation light from the detector material as signals.

15. The detector assembly according to claim 13 , wherein the active detector material forms a semiconductor detector, with which electrical signals can be read.

16. The detector assembly according to claim 13 , wherein the evaluation device comprises a storage device in which value combinations of colour parameters corresponding to known material compositions are stored.

17. The detector assembly according to claim 13 , wherein said at least one detector comprises a front face and a rear face, wherein:

a space between the front face and the rear face of the detector element is filled with a plurality of regions of a first detector material and at least one region of a second detector material, and each region connects the front face to the rear face of the detector element; and

wherein an energy deposition takes place in at least the regions of the first detector material as a function of art angle of incidence of the emitted radiation on the detector element.

18. A method for identifying nitrogen-containing explosives in material samples comprising;

providing a detector assembly with at least one detector element comprising an active detector material, a detection device being coupled to the detector element and receiving signals from the detector element, and an evaluation device which detects a distribution of energies deposited in the detector material as a function of the signals;

recording a spectrum of the energy deposited in the active detector material by the emitted radiation;

determining a first deposited energy as an integral of the recorded energy deposited over a first energy range extending from a first energy to a second energy, determining a second deposited energy as an integral of the recorded energy deposited over a second energy range extending from the second energy to a third energy, and determining a third deposited energy as an integral of the recorded energy deposited over a third energy range;

assigning a first colour parameter to the first deposited energy, a second colour parameter to the second deposited energy, and a third colour parameter to the third deposited energy;

determining a colour vector from the first colour parameter, the second colour parameter and the third colour parameter; and

comparing the colour vector with a volume in a three-dimensional colour parameter space associated with a predetermined material composition comprising a nitrogen-containing explosive so as to determine if the material sample includes the predetermined material composition.

19. The method according to claim 18 , wherein said material samples are at least one of the group of: a luggage item, a land mine or a cargo.

20. A method for determining the presence of a material composition in a material sample, said material sample emitting radiation, comprising:

recording a spectrum of the energy deposited in a detector material by the emitted radiation;

determining a first energy deposited in a first energy range, a second energy deposited in a second energy range, and a third energy deposited in a third energy range;

assigning a first colour parameter to the first deposited energy, a second colour parameter to the second deposited energy, and a third colour parameter to the third deposited energy; and

comparing the assigned colour parameters with predetermined values for the colour parameters corresponding to a predetermined material composition so as to determine the presence of the material composition;

detecting the emitted radiation with an angular resolution with a detector assembly, said detector assembly comprising at least one detector element having a front face and a rear face, wherein:

a space between the front face and the rear face of the detector element is filled with a plurality of regions of a first detector material and at least one region of a second detector material, and each region connects the front face to the rear face of the detector element: and

wherein an energy deposition takes place in at least the regions of the first detector material as a function of an angle of incidence of the emitted radiation on the detector element;

determining a preferred angle of rotation, for which the energy deposited in the first and/or second energy region is a maximum or a minimum; and

determining a direction parameter as a function of the ratio of the first and second deposited energies.

21. The method according to claim 20 , further comprising:

determining the direction parameter r for various detection directions, the respective detection direction being substantially normal to the front face of the detector element.

22. The method according to either claim 20 , further comprising:

determining a direction of the radiation source relative to the detector element as a function of the direction parameter r.