Performance and operation of the straw detector in the NA62 rare kaon decay experiment

The NA62 spectrometer should measure with good accuracy the direction and momentum of secondary charged particle originating from the decay region. In order to minimize multiple scattering, the spectrometer is operated in vacuum without physical separation from the upstream decay volume. The straw tracker has been chosen as the most promising detector to be operated in vacuum. The design is made without frames and flanges close to the beam and limits interactions from accompanying beam particles. The detector was successfully installed and commissioned in the fall of 2014. An overview of the design, construction and testing of the detector together with the first results of the detector performance and operation from the 2014 and 2015 runs are presented.