Speaker
Description
NA62 is a fixed-target experiment at the CERN SPS designed to measure the branching ratio of the very rare kaon decay $K^{+}\rightarrow \pi^{+} \nu \bar{\nu}$ with 10% precision. Measurements of time, momentum and direction of incoming beam particles are provided by a beam spectrometer called GigaTracKer.
The GigaTracKer is made of three stations of hybrid silicon pixel detector installed in vacuum ($\sim$10-6mbar). Each station consists of 18000 pixels of $300\times300\mu m^{2}$ area each, arranged in a matrix of $200\times90$ elements corresponding to a total area of $62.8\times27mm^{2}$. The beam particles, flowing at 750 MHz, are tracked in 4-dimensions by means of time-stamping pixels with the single hit time resolution reaching 115ps. This performance has to be maintained despite the beam irradiation amounting to a yearly fluence of $4.5 \times 10^{14}\ 1MeV\ n_{eq}/cm^{2}/200\ days$. In order to limit multiple scattering and beam hadronic interactions, the station material budget is reduced to 0.5%X0 by using micro channel cooling (first application in HEP).
We will present the detector design and performances during the NA62 data taking periods.
