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Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

Applications in daily life and in technology

Look at some applications in daily life and in technology.

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Hand baggage security checks

Baggage screening has been established worldwide to enhance air traffic security and is performed by means of so-called X-ray scanners. These X-ray scanners are designed in a way that only a very small fraction of the X-rays used for internal screening can be measured outside the machine.

grauer IonisationsrauchmelderSource: Firma Apollo

Type approval of ionisation smoke detectors (ISD)

Ionisation smoke detectors (ISD) are smoke detectors using radioactive substances, in most cases americium-241 with activities between 15 and 40 kilobecquerels. The radioactive material is usually applied to a backing layer. The radiation emitted from the foil ionises the air in the ISD. An electric voltage applied within the ISD produces an ionisation current. If fire aerosols enter the ISD through its vents, the size of the ionisation current changes. This change is detected electronically and is used for setting off the alarm.

Type approvals pursuant to Radiation Protection Ordinance (StrlSchV)

The type approval procedure for equipment and devices in which radioactive substances are inserted is regulated by §§ 25 to 27 together with Annex V of the “Ordinance on the Protection against Damage and Injuries Caused by Ionizing Radiation” (Radiation Protection Ordinance – StrlSchV).

According to the Radiation Protection Ordinance, the Federal Office for Radiation Protection (BfS) is the competent authority for granting type approvals. In granting a type approval the competent authority confirms that the essential radiation protection features of the tested prototypes comply with the requirements laid down in §§ 25 and 26 in connection with Annex V StrlSchV.


Radioactive substances in watches

Among others, luminous paints are used in watch dials to ensure that they can also be recognised in the dark. The luminous paints are stimulated to glow by a radioactive substance. Until well in the 60ties, the luminous dials of wrist watches and alarm clocks were marked with radium(Ra-226)- or promethium (Pm-147)-containing luminous paints. Such watches are no longer produced today. This is not so much due to the radiation exposure to the persons wearing the watches but to the radiological risk for the persons manufacturing them.

Safety of sealed radioactive sources in Germany

About 100.000 sealed radioactive sources are used in Germany in industry, medicine, research and in agriculture. The most common areas of use for sealed sources in industry lie in the fields of calibration, material testing, product irradiation and sterilisation as well as fill level and density measurement. Sealed sources in medicine are primarily used in radiation therapy and blood irradiation. The most commonly used radionuclides in these sources are cobalt-60, iridium-192, caesium-137, strontium-90 or americium-241.

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