Towards more sensitive radioactivity measurements

A radiopure capacitor (a fundamental electronics component) that is suited to be used in gamma-ray detectors operating underground has been developed during a recent study. This new 'radiopure' capacitor has much less radioactivity compared to what is naturally present in a normal capacitor and fills a gap in equipment needed to measure low radioactivity levels.

For deep underground measurements, specially designed detectors made from selected radiopure materials are fundamental to guarantee accurate results and reliable measurements since signals from electronics (capacitors, transistors, etc.) can swamp the weak signal from a sample. The activities of for example uranium and thorium in this new capacitor are more than 100 times reduced compared to a conventional capacitor in, e.g., a TV or radio.

Natural radioactivity is present everywhere. The human body for example contains about 6000 Becquerel (Bq, the unit for activity). It is important to be able to measure very low activity levels (mBq-levels, which are 10 million times lower than what is naturally present in a human) in order to trace certain processes in nature or industry. Since radiation-detectors also contain natural radioactivity detectors from radiopure materials are needed to detect low-levels of radioactivity.

The best gamma-ray spectrometry measurements are performed underground in order to avoid the background of cosmic rays. Due to this development, low-level radioactivity measurements are becoming increasingly important in many fields, from tracing radionuclides from Fukushima around the world and detecting illegal nuclear activities to developing reference materials for food monitoring. In such cases detecting specific radionuclides is a way of searching for fingerprints from certain processes in nature or industry.

Source: European Commission, Joint Research Centre