SCINTILLATION DETECTOR WITH A HIGH COUNT RATE

Abstract

The invention concerns a scintillation detector with which high count rates and/or high resolutions are possible. The scintillator of the claimed scintillation detector is formed from pixels (2), which are separated from each other by interstices (4). Alternatively or additionally, the surface of the scintillator is divided by grooves into pixels (2). Such a structure enables not only a particularly high resolution. When multiple detector modules are used, it also allows high count rates in the range of roughly 20 MHz.

Claims

1. Scintillation detector having a scintillator, a light readout unit, in particular a photomultiplier (6), and evaluation electronics (9), characterized in that the scintillator is formed from pixels (2), which are separated from each other by interstices (4), and/or whose surface is pixelated by grooves.

2. Scintillation detector according to claim 1, characterized in that the grooves and/or interstices (4) are filled with reflection material for the light to be detected.

3. Scintillation detector according to the preceding claim, characterized in that the reflection material consists of barium sulfate.

4. Scintillation detector according to claim 1, characterized in that the distance between the pixels (2) generated by the interstices (4) amounts to at least 100 μm and/or the grooves are at least 100 μm wide.

5. Scintillation detector according to claim 1, characterized in that the pixels (2) are up to 6 mm, preferably up to 3 mm long and/or up to 6 mm, preferably up to 3 mm wide and/or that the pixels (2) are at least 3 mm long and/or at least 3 mm wide.

6. Scintillation detector according to claim 1, characterized in that the pixels (2) contain 6Li.

7. Scintillation detector according to claim 1, wherein the scintillator comprises a substrate (1) for the scintillation material (2), which generates light flashes in response to incident radiation, which has a lower index of refraction than the scintillation material (2).

8. Scintillation detector according to claim 1, wherein the scintillator comprises a substrate (1) for the scintillation material (2), which generates light flashes in response to incident radiation, and wherein a light absorbing and/or light reflecting adhesive layer is installed between the substrate (1) and the scintillation material (2).

9. Scintillation detector according to claim 1, characterized in that pixels of the light readout unit, in particular the anodes of a multi-anode photomultiplier, are up to 6 mm, preferably up to 3 mm, long and/or up to 6 mm, preferably up to 3 mm, wide and/or that the pixels of the light readout unit, in particular the anodes of a multi-anode photomultiplier, are at least 3 mm long and/or at least 3 mm wide.

10. Scintillation detector according to claim 1, characterized in that the base surface of the evaluation electronics does not exceed the size of the front surface of the light readout unit (multi-anode photomultiplier).

11. Scintillation detector according to the preceding claim, characterized in that the scintillation detector is formed from a multiplicity of modules.

12. Scintillation detector according to claim 1, characterized in that the evaluation electronics comprises one or more integrated electronic components, which conduct an amplification and noise filtering of the individual signals of the pixels of a light readout unit (multi-anode photomultiplier).

13. Scintillation detector according to claim 1, characterized in that the evaluation electronics comprises a programmable logic device with internal storage areas, which takes over a number of tasks, specifically in particular a setting of the measurement modes and/or of the comparator thresholds of integrated electronic components as well as registration of logic comparator signals that are summed up in a chronological order in internal storage places, just like also of data of an analog-to-digital converter, which are also summed up in internal storages.

Description

[0047] It shows

[0048] FIG. 1: Scintillation detector in a sectional view;

[0049] FIG. 2: Scintillator seen in top view;

[0050] FIG. 3: Scintillator with a carrier, whose index of refraction is bigger than the index of refraction of the scintillation material;

[0051] FIG. 4: Scintillator with a carrier, whose index of refraction is smaller than the index of refraction of the scintillation material;

[0052] FIG. 1 illustrates a scintillation detector according to the invention in a lateral sectional view.

[0053] The scintillation detector comprises a glass pane 1 as carrier for scintillation material, on which pixels 2 formed from Li-glass with an area of 6 mm×6 mm are attached by means of an adhesive layer 3. The pixels 2 formed from scintillation material have a distance respectively interstice between each other of 100 μm. The interstices between the pixels 2 are filled with barium sulfate. By means of an adhesive layer 5, a multi-anode photomultiplier 6 is attached to the pixels 2.

[0054] Through plug pins 7 of the multi-anode photomultiplier 6 and a frame 8, evaluation electronics 9 is downstream connected and connected to the multi-anode photomultiplier 6.

[0055] The carrier material, thus the glass pane 1, has a lower index of refraction than the scintillation material, thus the pixels 2, in order to avoid cross-talk in a further improved manner.

[0056] During operation, neutrons hit the scintillation detector according to the arrow display.

[0057] The behind the scintillator with the components 1, 2, 3, 4 arranged further components of the detector, thus the photomultiplier 6 as well as the evaluation electronics 9, are as shown in FIG. 1 laterally not protruding the scintillator in order to enable a modular structure in a suitable manner. In top view seen on the glass pane 1, the base surface of the evaluation electronics and the front surface of the multi-anode photomultiplier thus do not protrude the glass pane 1.

[0058] FIG. 2 shows the scintillator in a view seen on the pixels 2, which has an area (surface) of 6 mm×6 mm.

[0059] FIGS. 3 and 4 show each a scintillator with a pixel 2, in which a light flash has been generated due to an incident neutron. Starting from area 11, the light spreads according to the arrow display. In case of FIG. 3, the index of refraction of the carrier material 1 formed from glass is bigger than the index of refraction of the pixels 2. In case of FIG. 4, the index of refraction of the carrier material 1 formed from glass is smaller than the index of refraction of the pixels 2. In case of FIG. 3, an unwanted cross-talk may occur due to refraction and reflection. This is avoided in the case of FIG. 4.

[0060] When the index of refraction of the Li-glass 2 as shown in FIG. 3 is lower than the one of the carrier glass 1, the adhesive layer 3 then has no mentionable influence on the reflection property of the light.

[0061] In this case, by means of refraction, light that is emitted from the scintillation process in the Li-glass 2 in direction of the carrier glass 1 enters the neighboring pixels 2. Thereby, the pixel may cross-talk between each other, which leads to worse space-resolution as well as also to higher noise.

[0062] When the index of refraction of the Li-glass 2 as shown in FIG. 4 is higher than the one of the carrier glass 1, the adhesive layer 3 has then no mentionable influence on the reflection property of the light. In this case, as shown in FIG. 4, an inner total reflection takes place so that no cross-talk occurs between the pixels 2.

[0063] The adhesive 3 may however alternatively or additionally be chosen such that it absorbs and/or reflects backwards in direction of glass pane 1 scattered light. Hereby, cross-talk is prevented as well.