The (optical) properties of the phantoms can be adjusted almost at will over a wide range. They can be defined according to customer specifications or modeled on a specific material.

1. the requirements for the phantom are discussed with the customer:

Requirements for optical properties: Here, either the customer can define the properties, or the ILM can develop optical properties by researching the literature or measuring the materials to be imitated. These can be defined either for individual wavelengths or within a spectral range.

Requirements for the material: The choice of matrix materials physical parameters can also be influenced. Depending on the material used, the parameters refractive index, hardness, thermal conductivity, acoustic hardness, aggregate state (solid/liquid) and long-term stability, for example, can be influenced within certain limits.

Requirements for the geometric shape of the phantoms: The phantom material can be cast in various geometric shapes. The spectrum ranges from quasi semi-infinite, homogeneous cubes, layered or structured phantoms up to 3D – Free-form shapes including inclusions. 

2. development of the recipe:

The ILM has a large number of well-characterized scattering and absorber substances. By combining these materials, a wide range of spectral optical properties (absorption coefficient, (effective) scattering coefficient, asymmetry factor) can be set. For example, various mineral oxide particles (TiO2, ZrO2, AlO, ZnO) with different size distributions are used as scatterers. The spectral behavior of the scattering coefficient and the anisotropy factor can be influenced by the choice or combination of scatterers. Furthermore, approx. 40 different absorbing substances are available with the help of which the absorption spectrum of many materials can be simulated. These substances are used to create an optimized recipe according to which the phantom material is produced.

3. production of the material and potting

The phantom material is produced after the casting mold (solid materials) has been provided or, if necessary, manufactured. The emphasis here is on excellent homogeneity of the material. The materials are then cured bubble-free in the molds using a vacuum process. As standard, layer samples of different thicknesses are produced from the same material for subsequent characterization.

4. characterization of the materials

Each manufacturing process is concluded with the quality control of the material. The optical properties are determined using suitable methods, e.g. with an integrating sphere measuring station, on the basis of the layer samples cast with the material (optical characterization) and checked for compliance with the recipe specifications. The actual optical parameters are made available to the client in the form of a report and as data.