The PIP-II Reference Design Report

Abstract

The Proton Improvement Plan-II (PIP-II) is a high-intensity proton facility being developed to support a world-leading neutrino program over the next two decades at Fermilab. PIP-II is an integral part of the U.S. Intensity Frontier Roadmap as described in the Particle Physics Project Prioritization Panel (P5) report of May 2014 [1]. As an immediate goal PIP-II is focused on upgrades to the Fermilab accelerator complex capable of providing a beam power in excess of 1 MW on target at the initiation of LBNF [1,2] operations. PIP-II is a part of a longer-term concept for a sustained campaign of upgrades and improvements to achieve multi-MW capabilities at Fermilab. PIP-II is based on three major thrusts. They are (1) the recently completed upgrades to the Recycler and Main Injector (MI) for the NOvA experiment, (2) the Proton Improvement Plan [3] currently underway, and (3) the Project X Reference Design [4]. Note that:  The Proton Improvement Plan (PIP) consolidates a set of improvements to the existing Linac, Booster, and Main Injector (MI) aimed at supporting 15 Hz Booster beam operation. In combination, the NOvA upgrades and PIP create a capability of delivering 700 kW beam power from the Main Injector at 120 GeV;  The scope of the Project X Reference Design Report was aimed well beyond PIP. It described a complete concept for a multi-MW proton facility that could support a broad particle physics program based on neutrino, kaon, muon, and nucleon experiments [5,6]. The Project X conceptual design has evolved over a number of years, incorporating continuous input on physics research goals and advances in the underlying technology development programs [7,8,9]. PIP-II, to high degree, inherits these goals as the goals for future developments and upgrades. This document (PIP-II Reference Design Report) describes an initial step in the development of the Fermilab accelerating complex. The plan described in this Report balances the far-term goals of the Laboratory's long baseline neutrino mission with the near- and mid-term goals identified at the Snowmass workshop [10] and endorsed by the P5 report [1].