Integration Test and Verification

After delivery of all externally developed components and units to MPIfR, the subsystem has been integrated and tested in a dedicated cleanroom laborato­ry. The optical alignment has been achieved by controlling the adjustments via a 3D coordinate measurement system with an accuracy of better than 3microns.

On the left hand picture you see the numeric controlled probe head that probes all optical elements of the cartridge including the horn antenna aperture references. With this method we were able to align the single elements with an accuracy of 15microns in position and better than 30 arcsec in angle. A basis for this, of course, is also the high precision machining of all parts in the institute’s workshop.

The success of this method was very important because the verification of the submillimeter beam for the cooled unit takes about 4 weeks total test time. Therefore a necessary re-adjustment would have been very time expensive … 

The 14 submillimeter quasi optical beams and their alignment have been verified on an antenna test range built at MPIfR for this purpose. These measurements base on the signal processing in an ABmm vector analyzer. The photographs below show the setup for the antenna measurements of the LOU Flight Model. On left hand picture the test cryostat for the LO (cooled to 120K) is connected to the Nitrogen gas chamber containing the 5-axis movement stage of the ATR hoisting the detector system for the antenna measurement (mid picture). On the right hand you see the control screens of thesetup and an engineer after a long test campaign …