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A Low Cost Picoseconds Precision Timing and Synchronization Over A Hundred Kilometer

Alice Renaux, Ronic Chiche, A. Martens, Antoine Back, Paul-Éric Pottie, Daniel Charlet

Abstract

Large-scale systems, such as very large accelerators used for fundamental research, require the implementation of precise timing and synchronization systems over distances of several tens of kilometers. A very high precision has been demonstrated by the use of costly and complex clock distribution systems. However, many devices, such as accelerator diagnostics or large-scale detectors, only require picosecond precision. An approach exploiting the CERN White Rabbit protocol, deployed and enhanced on an electronic system capable of generating arbitrary frequencies with Hertz precision, is proposed here. Results of performance tests for the synchronization of a laser system, typically employed as a diagnostic for electron/positron beam polarimetry in accelerators, are provided in this Paper. We demonstrate that without implementing corrections for environmental changes, as temperature drifts, the system can synchronize a pulsed laser with picoseconds precision over a hundred kilometers, exhibiting drifts of a few picoseconds. This work paves the way for a low-cost implementation of picosecond synchronization of accelerator components and large-scale detectors.

A Low Cost Picoseconds Precision Timing and Synchronization Over A Hundred Kilometer

Abstract

Large-scale systems, such as very large accelerators used for fundamental research, require the implementation of precise timing and synchronization systems over distances of several tens of kilometers. A very high precision has been demonstrated by the use of costly and complex clock distribution systems. However, many devices, such as accelerator diagnostics or large-scale detectors, only require picosecond precision. An approach exploiting the CERN White Rabbit protocol, deployed and enhanced on an electronic system capable of generating arbitrary frequencies with Hertz precision, is proposed here. Results of performance tests for the synchronization of a laser system, typically employed as a diagnostic for electron/positron beam polarimetry in accelerators, are provided in this Paper. We demonstrate that without implementing corrections for environmental changes, as temperature drifts, the system can synchronize a pulsed laser with picoseconds precision over a hundred kilometers, exhibiting drifts of a few picoseconds. This work paves the way for a low-cost implementation of picosecond synchronization of accelerator components and large-scale detectors.
Paper Structure (5 sections, 7 figures)

This paper contains 5 sections, 7 figures.

Table of Contents

  1. Introduction
  2. The Idrogen system
  3. The test setup
  4. Discussion
  5. Conclusion

Figures (7)

  • Figure 1: Views of the Idrogen board.
  • Figure 2: Diagram of the implemented test setup, see text for details.
  • Figure 3: Power spectral density of phase noise for the (i) free running laser; (ii) the SIC output with respect to the reference; (iii) the technical noise of the laser loop on the SIC output; (iv) the laser output with respect to the reference.
  • Figure 4: Power spectral density of phase noise for the (iv) the laser output with respect to the reference with 10 m, 5 km, 50 km and 100 km fibre links. A difference can be spotted with the 100 km where the noise is slightly larger above 300 Hz. Preliminary investigations suggest that this might be due to a change of the measurement setup where amplifiers have been added after the 50 Ohm splitter.
  • Figure 5: Measurement of the overlapped allan deviation of the laser locked on the SIC with respect to the SMB reference, for various fibre length.
  • ...and 2 more figures