EN 62022:2007 – nstalled monitors for the control and detection of gamma radiations contained in recyclable or non-recyclable materials transported by vehicles

4 Design requirements
4.1 General characteristics The equipment is a warning system designed to detect radioactivity of gamma emitters contained in recyclable or non-recyclable materials, issuing a visual and/or audible alarm, when the signal from the radiation detection system exceeds an alarm threshold.  The alarm threshold is not a fixed value, but an expected value depending on the measuring conditions, e.g. the material and energy ranges expected.
The equipment shall give indications linked to the fluence rate of gamma photons incident to the radiation detection assembly. The energy range of the gamma photons detected by the equipment shall be specified by the manufacturer, at least between 50 keV and 1 500 keV.
The alarm shall be activated if at least one of the indications issued from one of the detection assemblies, after treatment and correction of possible disruptive effects, exceeds an alarm threshold.
In the case of the dynamic mode (the vehicle passing the equipment) alarm occurs when there is a statistically significant increase in the detected fluence rate of gamma photons when the vehicle is passing the detection system. This fluence may however be less than that due to normal background. In the case of the static mode (vehicle stationary within the equipment) an alarm occurs when the fluence rate of gamma photons detected is greater than a pre-established level.
4.2 Configuration  The equipment is composed of one or several radiation detection assemblies adjacent to the vehicle in the static mode and close to the vehicle whilst it passes in the dynamic mode, and an information treatment assembly, linked to an alarm assembly.The radiation detection assembly is the elementary device produced by the manufacturer, containing generally one or several contiguous radiation detectors.
The design shall be such that operation is possible with radiation detection assembly and information treatment assembly separated by at least 1 00 m.
The radiation detection assembly shall be designed to operate under all expected weather conditions. The equipment enclosure shall be such that it does not deteriorate during prolonged installation under these conditions and that access for repair shall be unhindered by corrosion. The radiation detection assembly could also be subjected to amounts of vibration due to the heavy vehicles being monitored.
The design shall be such as to withstand this vibration. The equipment shall meet the relevant requirements in relation to electromagnetic compatibility.
The reference point of the radiation detection assembly shall be clearly marked on the external surface. For the testing in free air, the orientation of the radiation detection assembly relative to the reference calibration direction shall be given in relation to its enclosure. Controls and adjustments which affect calibration and alarm settings shall be so designed that access to them can be limited to authorised persons.
EN 62022:2007 – nstalled monitors for the control and detection of gamma radiations contained in recyclable or non-recyclable materials transported by vehicles