If an incident occurs involving an actual or suspected increase in radioactivity, the NEOC can deploy various measurement instruments on an ad hoc basis, depending on the type of the incident. The sampling and measuring organisation also receives data from various mobile measuring systems.
NADAM mobile network
The NEOC operates the NADAM mobile network, a mobile monitoring and alarm network that measures gamma radiation levels. The mobile network comprises 30 autonomous sensors that can supplement the fixed NADAM network at short notice. These sensors are identical in function and design to those used in the fixed network. The transmission of data and the warning and alarm thresholds are determined on an ad-hoc basis, depending on how or where the mobile network is deployed.
On-call radiation protection service
Specialised personnel are on standby for deployment in the event of a minor local incident. Besides monitoring local radiation and contamination levels, the on-call team can also take immediate measures, localise and isolate sources, and assume an advisory role. The Paul Scherrer Institute (PSI) has an on-call organisation that is ready to leave within an hour. The Institute for Applied Radiophysics (CHUV) and Spiez Laboratory can also be mobilised.
Mobile monitoring units
Various mobile monitoring units are available in Switzerland. These are stationed at the nuclear power and temporary storage facilities, the Paul Scherrer Institute (PSI), the FOPH’s Environmental Radioactivity Section (URA), the Institute for Applied Radiophysics (CHUV) and Spiez Laboratory. These mobile monitoring units measure radiation and contamination levels and collect environmental samples. The readings are subsequently transmitted to the NEOC database directly from the field. If necessary, the NEOC can arrange for further readings to be taken from an affected area. A number of laboratories are on hand to analyse the samples. Some of the mobile units (e.g. at the URA, CHUV and Spiez Laboratory) also have gamma spectrometry equipment (i.e. mobile germanium radiation detectors) on site. These detectors can determine the nuclide composition of a contamination. This information is essential for determining what further action is required.
Support with monitoring from the cantons (KAMU NEOC)
If necessary, measurements can also be taken by the cantonal monitoring support teams (KAMU NEOC) at 104 monitoring sites across Switzerland. The measurements are taken by cantonal radiation protection teams or other trained personnel. The teams are approached by the NEOC in the event of an incident and measure local radiation levels in the respective canton. The readings provide the NEOC with additional data to its own NADAM data. The cantonal support teams can also take measurements at short notice at specific locations if a local radiological incident occurs.
Mobile laboratories
The sampling and measurement organisation has two mobile monitoring laboratories from Spiez Laboratory at its disposal. These mobile laboratories can measure radiation levels in the human body using a full-body counter and take samples with the germanium detector. A smaller detector is used for thyroid or sampling measurements. These measurements can determine whether a person has been internally contaminated with radioactivity. In addition, various hand-held devices are available for measuring dose rate and checking samples. One of the mobile laboratories can also be used as an operations centre or reception point for samples taken from other networks used by the sampling and measurement unit.
Mobile air sample collectors
Mobile air sample collectors are used to measure radioactivity in the air at specific times. The devices are electrically powered and are usually used at predefined locations, namely at specialist or cantonal laboratories. The NEOC determines the start and duration of sampling. After that, the two filters (aerosol and activated carbon cartridge) are removed and analysed in the laboratory using gamma spectrometry. The following organisations have a mobile air sample collector: FOPH, CHUV, Spiez Laboratory, Paul Scherrer Institute, Swiss Federal Institute of Aquatic Research (Eawag), cantonal laboratories in the cantons of Aargau, Bern, Basel-Stadt, Graubünden, Lucerne, Ticino and Zurich.
Aerial and ground radiometry
Aerial and ground radiometry allows the NEOC to measure nuclide-specific radioactivity deposits on the ground. This is performed by a highly sensitive device installed in a helicopter which can measure a surface area of up to 100 km2 in around three hours. The readings are tracked online and can be analysed in detail after landing. The same measuring technique and software are used in vehicles for ground radiometry. The equipment is permanently installed on carrier vehicles and can be set up in less than half an hour. It is deployed in collaboration with the Swiss Air Force and the Armed Forces’ NBC EOC competence centre.
NBC Defence Corps
The NBC Defence Corps supports military operational forces and civilian authorities in detecting radioactivity and biological and chemical warfare agents, for example after terrorist attacks or industrial accidents. It can also decontaminate people, vehicles and equipment. The Defence Corps is important for ensuring the resilience of the sampling and measurement organisation. It is part of the NBC EOC competence centre in Spiez.