Laboratory for radioecology and radiation protection

Nuclear-physical measuring methods in industrial measurement technology

Impressions

The team

Laboratory Head

Non-Public Person

Research assistant

Non-Public Person

Teaching

Nuclear physics measurement technologies are used in many industrial measurement processes. The laboratory should help to make the underlying physical principles understandable. Since handling ionising radiation always involves risks, the subject of radiation protection is an integral part of the education.

Laboratory topics:

Examination and calibration of electronic personal dosimeters. Personal dosimetry, radiometry - application example: Weld seam testing with γ- or X-radiation.
Investigation, calibration and application of contamination monitors. In addition to dose control, protection against radioactive contamination is a central concern in radiation protection. Contamination monitors allow quantitative detection of even very small traces of radioactivity, provided that they are handled correctly and calibrated carefully.
High-resolution γ-spectrometry with a Ge semiconductor detector. γ-spectrometry is ideally suited for identifying different radioactive nuclides. The method is used for monitoring nuclear or nuclear medicine facilities, as well as for the examination of environmental and food samples.
Density and thickness measurement. Radiometric density and thickness measurements are examples of industrial use. They are used, for example, on rolling mills in the steel industry, or in foil, sheet metal, paper and glass production. Radiometric density measurement methods are particularly suitable for food and petroleum processing.
Moisture measurements with a neutron probe. The method is based on the particularly strong braking effect of hydrogen with fast neutrons. The method has a wide range of applications. Example: Combined probes for density and moisture determination are used in road construction and civil engineering (Troxler probe).
X-ray fluorescence analysis. If material samples are irradiated with ionising radiation, the atoms are excited to emit characteristic X-rays. By measuring them, an unambiguous, non-destructive determination of the elemental composition of the sample is possible.
X-ray computer tomography. Tomography is an analytical method in which objects are trans-illuminated from very many different directions and subsequently the three-dimensional structure (e.g. the density distribution) inside the object can be calculated from the projections with the aid of mathematical algorithms.

Interesting techniques

X-ray fluorescence analysis (XRF)

The measuring equipment for X-ray fluorescence was set up as part of a Bachelor's thesis. The samples, including liquids, are irradiated from above with a narrow beam from an X-ray tube and then emit fluorescence radiation, which is spectrally analysed with a high-resolution Si detector. The sampling location is marked with a laser and can be documented with a camera.

High-resolution γ-spectrometry

Measuring equipment with a Ge semiconductor spectrometer for the detection of γ-radiation. A more than 10 cm thick lead-copper Plexiglas shield (lead castle) as well as filtering of the air inside the lead castle serve to efficiently reduce the natural radiation background.

Computer tomography (CT)

Samples up to 5 cm in diameter are trans-illuminated by an X-ray beam and the projections are recorded by a digital X-ray image detector. The samples are placed on a turntable so that several hundred projections can be taken at different angles. From this, a powerful computer calculates the 3D density distribution in the sample.

Equipment

α-spectrometry

Two α-spectrometers with high-resolution PIPS detectors, CANBERRA.

Large-area α-detector with anticoincidence shielding,

FAG Kugelfischer.

β-spectrometry

Two liquid scintillation spectrometers, type: TRI CARB 1000 and LSC 2560 TR/XL, Packard.

γ-spectrometry

Ge semiconductor detector with low-level measuring station, DSG and CANBERRA.

Myon detector

Measuring device for demonstrating the particle property of muons in the cosmic background radiation, self-installation.

Fog chamber

A diffusion cloud chamber is used to directly visualise α- and β-radiation in the ambient radiation (demonstration in the lecture).

Dosimetry and contamination control

Several measuring devices for the determination of the γ-local dose rate, one of them for H*(10) measurements with calibration.

Electronic personal dosimeters for the determination of Hp(10).

Various contamination monitors for the determination of α, β/γ and

H contaminations.

The radon concentration of the ambient air can be determined with a radon monitor.

A modern neutron SEM counter is used to measure the equivalent dose of neutron radiation.

Moisture, density and thickness measurement

Industrial measuring device for radiometric density and thickness measurement, Berthold.

Troxler probe for combined moisture and density measurement, Troxler.

Neutron moisture probe, Berthold.

X-ray fluorescence

Measuring station for material analysis with X-ray fluorescence, components from Amptek, self-installation.

Computer tomography

Demonstration device for computer tomography, self-installation

Device for X-ray computer tomography with digital X-ray image detector, Leybold.

Radiochemical laboratory

The radiochemical laboratory is used for sample preparation and radiochemical analysis (handling licence for open radioactive substances available; laboratory has room category RK1).

Radioactive materials

The laboratory has about 150 different radioactive sources in the form of sealed radioactive sources for irradiation and calibration purposes, as well as numerous radioactive standard solutions for radiochemical preparation work.