|Description:|| Thousands LOFAR Hi-band receivers will be installed in the fields to receive faint cosmic signals. Most of the time the environment is very hostile for electronic equipment. Especially high humidity can destroy the sensitive receivers in a short time. The fact is that we have a lot of rainy days in the Netherlands (and also in other county’s around us), so rain, fog and condensation are potential problems. But the receivers must work at least for 15 years in this outdoor environment.|
To protect the equipment we take two measures. First we shield the equipment from direct rain by placing the antennas into a housing. Still fog and condensation can destroy the receivers. The second measure is placing a layer of protective coating directly on the sensitive electronics. When this coating is applied properly, it will shield the electronics from water. At this point the skill of the supplier of the coated receivers is very important. After a lot of testing and improvements we (they) finally did succeed in protecting the receiver to a maximum level.
In the picture you see a few HBA receivers in an environmental test at ASTRON. The test, used to validate the receiver to work for about 15 years, is called HAST (Highly Accelerated Stress Test). By increasing the temperature to 85 degrees Celsius, and the humidity to 85%RH on a working receiver, the effects of failure will be visible much sooner than in normal environmental circumstances.