Design, construction and testing of the straw tracker for the NA62 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. It can be designed without frames and flanges close to the beam and so limits interactions from accompanying beam particles. The straws are made out of 36 μm thick polyethylene terephthalate film and are made through ultrasonic welding in the axial direction. They are coated with 50 nm of copper and 20 nm of gold on the inside of straw. The construction of the modules is in full swing and the detector will be installed in the fall of 2014 in order to be ready for the first physics run. We report on the design, construction and testing of the detector modules.