FAST LUMINOSITY MONITORING USING DIAMOND SENSORS FOR THE SUPER FLAVOUR FACTORY SUPERKEKB

Super luminous flavor factories, as SuperKEKB in Japan, aim to achieve very high luminosity thanks to a newly employed concept, the nano-beam scheme, where ultra-low emittance beams collide at very large crossing angle. Luminosity optimisation and dynamic imperfec-tions require fast luminosity measurements. The aimed precision, 10−3 in 10 ms, can be achieved thanks to the very large cross-section of the radiative Bhabha process at zero-photon scattering angle. As a result of huge particle fluxes, diamond sensors are chosen to be placed just out-side the beam-pipe, downstream of the interaction point, at locations with event rates consistent with the aimed pre-cision and small enough contamination by backgrounds from single-beam particle losses. We will present the re-sults concerning the investigation of the optimal position-ing of our diamond sensors, taking into account the rate of Bhabha particles as well as their interactions with the beam pipe material