The Gigatracker, the silicon beam tracker for the NA62 experiment at CERN

The Gigatracker is the NA62 beam tracker. It is made of three 63 . 1 m m × 29 . 3 m m stations of 300 μ m × 300 μ m hybrid silicon pixel detectors installed in vacuum ( ∼ 1 0 − 6 m b a r ). The beam particles, flowing at 750 M H z , are traced in 4-dimensions by mean of time-stamping pixels with a design resolution of 200 p s . This performance has to be maintained despite the beam irradiation amounting to a yearly fluence of 2 × 1 0 14 1 MeV n eq ∕ cm 2 . The detector material minimization is paramount, as the detector faces the full beam. The station material budget is reduced to 0 . 5 % X 0 by using (HEP world first) micro-channels cooling. We will describe the detector design and performances during the NA62 runs.