The laser-based gain monitoring system of the calorimeters in the Muon g-2 experiment at Fermilab

44siThe Muon g-2 experiment, E989, is currently taking data at Fermilab with the aim of reducing the experimental error on the muon anomaly by a factor of four and possibly clarifying the current discrepancy with the theoretical prediction. A central component of this four-fold improvement in precision is the laser calibration system of the calorimeters, which has to monitor the gain variations of the photo-sensors with a 0.04% precision on the short-term (∼ 1 ms). This is about one order of magnitude better than what has ever been achieved for the calibration of a particle physics calorimeter. The system is designed to monitor also long-term gain variations, mostly due to temperature effects, with a precision below the per mille level. This article reviews the design, the implementation and the performance of the Muon g-2 laser calibration system, showing how the experimental requirements have been met.reservedmixedAnastasi A.; Basti A.; Bedeschi F.; Boiano A.; Bottalico E.; Cantatore G.; Cauz D.; Chapelain A.T.; Corradi G.; Dabagov S.; Falco S.D.; Meo P.D.; Sciascio G.D.; Stefano R.D.; Donati S.; Driutti A.; Ferrari C.; Fienberg A.T.; Fioretti A.; Gabbanini C.; Gibbons L.K.; Gioiosa A.; Girotti P.; Hampai D.; Hempstead J.B.; Hertzog D.W.; Iacovacci M.; Incagli M.; Karuza M.; Kaspar J.; Khaw K.S.; Lusiani A.; Marignetti F.; Mastroianni S.; Miozzi S.; Nath A.; Pauletta G.; Piacentino G.M.; Raha N.; Santi L.; Smith M.; Sorbara M.; Sweigart D.A.; Venanzoni G.Anastasi, A.; Basti, A.; Bedeschi, F.; Boiano, A.; Bottalico, E.; Cantatore, G.; Cauz, D.; Chapelain, A. T.; Corradi, G.; Dabagov, S.; Falco, S. D.; Meo, P. D.; Sciascio, G. D.; Stefano, R. D.; Donati, S.; Driutti, A.; Ferrari, C.; Fienberg, A. T.; Fioretti, A.; Gabbanini, C.; Gibbons, L. K.; Gioiosa, A.; Girotti, P.; Hampai, D.; Hempstead, J. B.; Hertzog, D. W.; Iacovacci, M.; Incagli, M.; Karuza, M.; Kaspar, J.; Khaw, K. S.; Lusiani, A.; Marignetti, F.; Mastroianni, S.; Miozzi, S.; Nath, A.; Pauletta, G.; Piacentino, G. M.; Raha, N.; Santi, L.; Smith, M.; Sorbara, M.; Sweigart, D. A.; Venanzoni, G