Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam
- 1.4k Downloads
During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of ~1.8 × 1017 p.o.t., with the proton beam made of bunches, few ns wide and separated by 100 ns. This beam structure allows a very accurate time of flight measurement of neutrinos from CERN to LNGS on an event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing synchronization have been substantially improved for this campaign, taking advantage of additional independent GPS receivers, both at CERN and LNGS as well as of the deployment of the “White Rabbit” protocol both at CERN and LNGS. The ICARUS-T600 detector has collected 25 beam-associated events; the corresponding time of flight has been accurately evaluated, using all different time synchronization paths. The measured neutrino time of flight is compatible with the arrival of all events with speed equivalent to the one of light: the difference between the expected value based on the speed of light and the measured value is δt = tof c −tof ν = 0.10 ± 0.67stat. ± 2.39syst. ns. This result is in agreement with the value previously reported by the ICARUS Collaboration, δt = 0.3 ± 4.9stat. ± 9.0syst. ns, but with improved statistical and systematic accuracy.
KeywordsNeutrino Detectors and Telescopes
- S. Bertolucci, Review of other experiments at Gran Sasso, talk given at the NEUTRINO2012 conference, June 3–9, Kyoto, Japan (2012).Google Scholar
- P. Alvarez and J. Serrano, Time transfer techniques between CERN and LNGS, CERN BE-CO-HT Internal Note (2011), http://www.ohwr.org/projects/cngs-time-transfer/documents.
- Agilent (Acqiris) DP110 and AC240, http://www.agilent.com.
- Master clock GPS 2000, http://www.esat.it/EN/default.htm.
- M. Lipinski et al., Performance results of the first White Rabbit installation for CNGS time transfer, private communication, to be submitted to IEEE Transactions (2012).Google Scholar
- METAS measurement reports No. 119–00210, No. 119–00209, No. 117–00611, No. 117–00612, http://www.ohwr.org/documents/113/.
- Physikalisch-Technische Bundesanstalt (PTB), Relative calibration of the GPS time link between CERN and LNGS, http://www.ohwr.org/documents/114/.