Solid body

1. A method for adjusting, calibrating or function checking of a turbidity sensor, comprising the steps:

providing a solid body that is transparent for light of at least a first wavelength, wherein the solid body contains a first region, the first region containing plurality of microcracks, and wherein the first region is assigned a turbidity value;

providing a turbidity sensor comprising a light transmitting unit and at least one light receiving unit;

positioning the solid body on the turbidity sensor;

transmitting light of the first wavelength from the light transmitting unit into the first region of the solid body, whereby the light is scattered by the microcracks in the first region;

receiving with at least one light receiving unit light scattered by the microcracks in the first region;

measuring a turbidity value from the received light;

comparing the measured turbidity value with the assigned turbidity value of the first region; and

adjusting, calibrating, or function testing the turbidity sensor based on comparing the measured turbidity value with the assigned turbidity value.

2. A method for manufacturing a solid body for calibrating a turbidity sensor, comprising the steps:

providing a solid body which is transparent for light of at least a first wavelength;

focusing a laser into a first region of the solid body at a focal point;

ionizing and crystalizing the solid body at or near the focal point thereby forming a microcrack;

moving the focal point of the laser to a different point in the first region;

repeating the focusing, microcrack forming, and moving steps at different focal points until a desired microcrack density is generated;

measuring a turbidity value of the first region with a turbidity-measuring apparatus; and

assigning the turbidity value to the first region.

3. The method for manufacturing a solid body for calibrating a turbidity sensor as claimed in claim 2 , the method further comprising the steps:

focusing the laser into a second region of the solid body at a focal point;

ionizing and crystalizing the solid body at or near the focal point in the second region thereby forming a microcrack;

moving the focal point of the laser to a different point in the second region;

repeating the focusing, microcrack forming, and moving steps at different focal points until a desired microcrack density is generated;

measuring a turbidity value of the second region with the turbidity-measuring apparatus; and

assigning the turbidity value to the second region.

4. The method for manufacturing a solid body as claimed in claim 2 , wherein the solid body comprises one of the group of materials: glass, sapphire, diamond, polymethylmethacrylate, and polycarbonate.

5. The method for manufacturing a solid body as claimed in claim 2 , wherein at least one microcrack has dimensions of less than 1000 μm.

6. The method for manufacturing a solid body as claimed in claim 2 , wherein the microcrack density depends on the number, shape, size, and separation of the microcracks from one another and the microcrack density effects a scattering of incident light and is a measure for turbidity.

7. The method for manufacturing a solid body as claimed in claim 2 , wherein the microcracks are uniformly distributed.

8. The method for manufacturing a solid body as claimed in claim 2 , wherein the microcrack density is so embodied that the measure for turbidity is referenced to a turbidity standard liquid, such that the measure for turbidity can be expressed in at least one of the following turbidity units, FAU, FNU, FTU, NTU, EBC, TEF, ASBC and TU/F.

9. The method for manufacturing a solid body as claimed in claim 8 , wherein the turbidity standard liquid is formazine.