The Proton Power Upgrade (PPU) Project is critical to keep Spallation Neutron Source (SNS) at the international forefront and ensure continued leadership by maximizing the neutron flux available at the First Target Station (FTS) and providing the capability to drive a Second Target Station (STS). The PPU will upgrade the SNS Accelerator Complex to double its current proton beam power capability from 1.4 to 2.8 MW. The 2 MW delivered to the FTS will improve performance across the entire existing and future instrument suite, and the future STS would provide a wholly new capability in the form of a transformative new source optimized to produce the world’s highest peak brightness of cold neutrons.
Provisions for an accelerator power increase were made in the original SNS project, and these are being leveraged to provide a cost-effective means of doubling the beam power. Additionally, accelerator developments and operational experience over the last 10 years of operation provide a strong technical basis for much of the design. The plan for doubling the proton beam intensity capability per pulse is to increase the beam energy from 1.0 to 1.3 GeV and increase the average linear accelerator (linac) beam current from 26 to 38 mA.
The beam energy increase is accommodated by the addition of seven new Superconducting RF (SRF) Cryomodules in the existing space at the end of the linac tunnel. The seven new cryomodules will add 28 new cavities which will require the addition of 28 RF stations, including new low-level RF (LLRF) control systems. Due to obsolescence with the existing LLRF systems, a replacement system is required. The purpose of this LLRF Preliminary Design Review is to determine that the replacement system is at or above the 30-50 percent completion level.