Session P4a: T&F Transfer Utilizing Existing and Emerging Communication Systems

Muochrony: Time Synchronization/Dissemination with Cosmic Muons. The Role of INRIM and the way Toward a Muonic Disciplined Oscillator (u-DO)
G. Cerretto, Istituto Nazionale di Ricerca Metrologica (INRIM) | International Virtual Muography Institute (VMI); E. Cantoni, M. Sellone, INRIM | VMI; C. E. Calosso, INRIM; I. Gnesi, CREF, Centro Ricerche Enrico Fermi | The University of Torino - Department of Management | INFN LNF - Gruppo di Cosenza, Frascati | CERN | VMI; H.K.M. Tanaka, The University of Tokyo | VMI
Location: Seaview A/B
Date/Time: Thursday, Jan. 30, 9:43 a.m.

When a Cosmic Ray (CR) penetrates the atmosphere, hadronic collisions occur with air nuclei, giving way to the formation of a shower of secondary particles (called Extended Air Showers, EAS) whose main components are hadronic, electromagnetic, muonic, together with other phenomena like the fluorescent and Cherenkov effects and neutrino production from particle decays. Each EAS brings to the ground, over a mean area of a few square kilometers, about 10^6 secondaries, of which about 2% are relativistic muons, the most penetrating component of the shower, through air and ground. Because of these characteristics, muons can produce images of the interior of big objects like volcanoes or pyramids in the frame of a dedicated discipline called Muographic Imagery.
Within an EAS, single muons can be considered “simultaneous” events for the detectors within tens of nanoseconds. In addition, the difference in arrival times between two or more detectors is found to be highly stable over time, being affected by white gaussian noise. This stability makes them well-suited for applications related to timing (T) within the framework of an emerging branch of study called Muochrony, by analogy with the more established field of Muographic Imagery and another emerging technology called Muometry, oriented to muonic Positioning and Navigation (PN). Muographic Imagery, Muometry (i.e., PN), and Muochrony (i.e., T) are the main pillars of the muonic scientific discipline called Muography.
In this work, we present the results of an ongoing scientific collaboration between INRIM and MUOGRAPHIX, the University of Tokyo, on the possibility of synchronizing atomic clocks and disseminating reference atomic time scales using muons from cosmic rays induced EAS through an approach called CTS (Cosmic Time Synchronizer), ideated by the University of Tokyo and considered as the primary driver of Muochrony.
Details of the CTS technology/working principle and a description of the first CTS prototypal system installed at the INRIM RadioNavigation Laboratory will be presented, together with results of an initial metrological characterization and the first tests aimed at synchronizing different types of atomic clocks and disseminating UTC(IT) timescale to a final user exploiting cosmic muons.
Theory, simulations, and first metrological results identify CTS as a hectometer-to-kilometer-scale wireless clock network resynchronization scheme with a 10–100 ns precision, where EAS muons are used instead of radiofrequency or optical signals. The low interaction cross-section of EAS muons allows CTS to enable cheap, long-term wireless atomic clock synchronization and reference time scales dissemination within the EAS shower disc area with improved characteristics against jamming and spoofing. Suitable for indoor, underground, and underwater applications (bearing in mind the higher detector network granularity required with increasing water equivalent depth to be traversed by the muons in underground environments), CTS could potentially be considered a candidate to provide secure synchronization and reference time dissemination in critical applications as well as to complement GNSS in areas/environments not covered by its RF signals.
Finally, the INRIM project for realizing the prototype of a muonic Disciplined Oscillator (u-DO) will be presented, together with further Muochrony drivers enabling new cosmic muons-based technologies like nanosecond-level synchronization for structural monitoring, cryptography, and Positioning/Navigation (i.e., Muometry).