The DAΦNE luminosity monitor

DAΦNE, the Frascati Φ-factory, is an e+/e− collider with 2 interaction points (IPs). The center of mass energy is 1020 MeV and the design luminosity 4.2×1030 cm−2 s−1 in single bunch mode and 5×1032 cm−2 s−1 in multibunch mode. Between the possible electromagnetic reactions at the interaction point, single bremsstrahlung (SB) has been selected for the luminosity measurement. The SB high counting rate allows real-time monitoring, which is very useful during machine tune-up and moreover the narrow peak of the SB angular distribution makes the counting rate almost independent from the beam position at the IP. A description of the experimental set-up, calibration results and luminosity measurements is presented.