The phase averaging reference line system provides the RF phase reference, LO and clock signals to the LLRF and other accelerator sub-systems. The PIP-II linac has RF systems at three frequencies - 162.5 MHz, 325 MHz and 650 MHz. A temperature-stabilized, low-phase-noise oscillator is used as the master oscillator. Phase reference signals at 162.5 MHz, 325 MHz, and 650 MHz, along with LO signals at 182.5 MHz, 345 MHz, 670 MHz and LLRF clocks at 1320 MHz and 1300 MHz, are generated in temperature-controlled RF modules at each frequency section. A phase reference from each module travels to the next section, where it is doubled to produce required frequencies. The reference also travels alongside the accelerating cavities in the tunnel, allowing cavity probe and reference cables to temperature track and reduce measurement errors from temperature changes or phase drift.
@article{arxiv.2510.12960,
title = {Master Oscillator and Phase Reference Line Design for the PIP-II Linac},
author = {A. Syed and B. Vaughn and P. Varghese and E. Cullerton and S. Stevenson and D. Pieper and D. Peterson and J. Holzbauer and R. Madrak and A. Mosher and D. Klepec},
journal= {arXiv preprint arXiv:2510.12960},
year = {2025}
}
Comments
Low Level Radio Frequency Workshop (LLRF Workshop 2025)