Progress on Project X

Steve Holmes, project manager for the proposed Project X, wrote this week’s column.

Steve Holmes

Last week, about 70 people from the Project X collaboration gathered at Oak Ridge National Laboratory for the collaboration’s first meeting away from Fermilab. The selection of ORNL as the first non-Fermilab host was particularly appropriate because the laboratory’s Spallation Neutron Source is the first, and so far only, superconducting proton linear accelerator in the world capable of delivering in excess of one megawatt of beam power. This makes it an extremely valuable tool for learning about issues related to the proposed Project X accelerator at Fermilab.

Attendees at the meeting represented the 10 U.S. institutions and four Indian laboratories engaged in the Project X collaboration. In addition, interested colleagues from CERN and the European Spallation Source joined our presentations and discussions. We were treated to a wonderful Tennessee spring, featuring blooming dogwood and red bud, and enjoyed the traditional southern hospitality supplied by our hosts.

This meeting took place during a time when we’d been working closely with the Department of Energy to achieve Critical Decision-0, which would establish the mission need for Project X. In support of this goal, we have created a reference design that foresees a broad research mission for Project X. The accelerator would produce intense particle beams for experiments aimed at the exploration of the physics behind rare subatomic processes as well as long-baseline neutrino experiments. Project X would also provide research opportunities outside of high-energy physics and could serve as the first stage of a future Muon Collider.

The Project X reference design is based on a 3-GeV continuous-wave superconducting linear accelerator augmented by a pulsed linac that would accelerate protons from 3 to 8 GeV for transfer into our existing Recycler/Main Injector complex. We believe this configuration offers opportunities that are unique among facilities either in operation or in the design stage anywhere in the world.

The goals of our meeting were to discuss the technical basis for the reference design, identify technical issues and establish plans for the R&D effort over the next two years. This includes the assignment of particular R&D tasks to specific institutions. We also took advantage of the presence of a large number of SNS personnel to learn from their experiences in operating a high-intensity proton facility.

We made significant progress at understanding the design of the front end of the Project X linac, in particular, concepts for a wideband chopper that is the key to supporting multiple experiments with differing beam requirements. We addressed questions related to the superconducting acceleration systems, the promise of solid-state-based radio-frequency power sources, and the possibility of utilizing high-power lasers to create proton beams for accumulation in the Recycler by stripping electrons from negative hydrogen ion beams. These discussions, and several associated decisions, will directly feed into the update of the current reference design.

Our plans for Project X are moving ahead, and we are looking forward to reconvening for the next collaboration meeting this fall at Fermilab.