Before sent into space, the flight instruments are tested in vacuum and in different temperature ranges. A special magnetometer laboratory is use for the calibration of magnetometers.
IWF owns four different kind of vacuum chambers. The small vacuum chamber is a manually controlled, cylindrical vacuum chamber (160 mm diameter, 300 mm length) for small electronic components or printed circuit boards. It features a turbo molecular pump and a rotary dry scroll forepump. A pressure level of 10-10 mbar can be achieved.
The medium vacuum chamber has a cylindrical stainless steel body with the overall length of 850 mm and a diameter of 700 mm. A dry scroll forepump and a turbo molecular pump provide a pressure level of about 10-7 mbar. A target manipulator with two axes and an ion beam source are installed. This chamber mainly serves for functional tests of the ion mass spectrometer for BepiColombo.
The large vacuum chamber has a horizontal cylindrical stainless steel body and door, a vision panel, two turbo molecular pumps and a dry scroll forepump. A pressure of 10-7 mbar can be achieved. The cylinder has a diameter of 650 mm and a length of 1650 mm. During shutdown the chamber is vented with nitrogen. A target manipulator inside the chamber allows for computer-controlled rotation of the target around three mutually independent perpendicular axes. The vacuum chamber is enclosed by a permalloy layer for magnetic shielding. To enable the baking of structures and components (to outgas volatile products and unwanted contaminations), the chamber is equipped with a heater around the circumference.
The thermal vacuum chamber is fitted with two turbo molecular pumps, a dry scroll forepump, and an ion getter pump, which together achieve a pressure level of 10-6 mbar and allow quick change of components or devices to be tested. A thermal plate installed in the chamber and liquid nitrogen are used for thermal cycling in a temperature range between -160 °C and +140 °C. The vertically oriented cylindrical chamber allows a maximum experiment diameter of 410 mm and a maximum height of 320 mm.
Temperature tests are performed in two different temperature test chambers. One chamber allows verifying the resistance of electronic components and circuits to most temperatures that occur under natural conditions, i.e., -40 °C to +180 °C. It has a test space of 190 liters and is equipped with a 32-bit control and communication system. The second chamber is used for fast cycling electronic components and circuit. The temperature range is -70 °C to +180 °C. This chamber has a test space of 37 liters and is equipped with similar interfaces for communication.
In the magnetometer laboratory two three-layer magnetic shielding made from mu-metal are used for all basic magnetometer performance and calibration tests. The remaining DC field in the shielded volume is <10 nT with a field noise of <2 pT/√Hz at 1 Hz. A special Helmholtz coil system allows generating field vectors of up to ±30,000 nT around the sensor under test.
The magnetometer temperature test facility is used to evaluate magnetic field sensors between -170 °C and +220 °C in a low field and low noise environment. Liquid nitrogen is the base substance for temeperature regulation, which is accurate to ±0.1 °C. A magnetic field of up to ±100,000 nT can be applied to the sensor during the test cycles.
IWF also operates a large three-dimensional Merritt coil system in cooperation with the Zentralanstalt für Meteorologie und Geodynamik (ZAMG). It is located in the Conrad Observatory within a nature reserve at the outskirts of the Eastern Alps about 50 km SW of Vienna. The remoteness of the location guarantees an undisturbed surrounding for the absolute calibration of magnetic field sensors. The coil system has a side length of approximately three meters. Two pairs of coils along each axis enable a field homogeneity of better than 4x10-5 in a test volume of 200 x 200 x 200 mm in the center of the coil. The coil system features separate coils for Earth's field compensation and the dynamic range of the main coils is ±100,000 nT.