Project X Accelerator R&D Plan

Fermi National Accelerator Laboratory

关键词: Neutrino Beams;    Modifications;    Protons;    Decay;    Energy Range;   

DOI  :  10.2172/990839
RP-ID  :  FERMILAB-FN-0905
RP-ID  :  AC02-07CH11359
RP-ID  :  990839

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来源: UNT Digital Library

【 摘 要 】

Project X is a high intensity proton facility conceived to support a world-leading program in neutrino and flavor physics over the next two decades at Fermilab. Project X is an integral part of the Fermilab Roadmap as described in the Fermilab Steering Group Report. Project X is based on an 8 GeV superconducting H-linac, paired with the existing (but modified) Main Injector and Recycler Ring, to provide in excess of 2 MW of beam power throughout the energy range 60-120 GeV, simultaneous with at least 100 kW of beam power at 8 GeV. The linac utilizes technology in common with the ILC over the energy range 0.6-8.0 GeV. Beam current parameters can be made identical to ILC resulting in identical rf generation and distribution systems. This alignment of ILC and Project X technologies allows for a shared development effort. The initial 0.6 GeV of the linac draws heavily on technology developed by Argonne National Laboratory for a facility for rare isotope beams. It is anticipated that the exact configuration and operating parameters of the linac will be defined through the R&D program and will retain alignment with the ILC plan as it evolves over this period. Utilization of the Recycler Ring as an H{sup -} stripper and accumulator ring is the key element that provides the flexibility to operate the linac with the same beam parameters as the ILC. The linac operates at 5 Hz with a total of 5.6 x 10{sup 13} H{sup -} ions delivered per pulse. H{sup -} are stripped at injection into the Recycler in a manner that 'paints' the beam both transversely and longitudinally to reduce space charge forces. Following the 1 ms injection, the orbit moves off the stripping foil and circulates for 200 msec, awaiting the next injection. Following three such injections a total of 1.7 x 10{sup 14} protons are transferred in a single turn to the Main Injector. These protons are then accelerated to 120 GeV and fast extracted to a neutrino target. The Main Injector cycle takes 1.4 seconds, producing approximately 2.3 MW of beam power at 120 GeV. At lower proton energies Main Injector cycle times can be shorter, allowing a beam power above 2 MW in the range of proton energy between 60 GeV and 120 GeV. In parallel, because the loading of the Recycler only requires 0.6 seconds, up to four linac cycles are available for accumulation and distribution of 8 GeV protons from the Recycler. Total available 8 GeV beam power lies in the range of 100-200 kW, depending on the energy in the Main Injector. Primary modifications to the existing accelerator complex to support Project X include integration of an H{sup -} injection system, a new RF system, a new extraction system, and measures to mitigate electron cloud effects, in the Recycler Ring. The Main Injector would need a new RF system, measures to preserve beam stability through transition, and measures to mitigate electron cloud effects. Finally, substantial modifications to the existing NuMI target station will be required to support >2 MW operations. It is anticipated that Project X configured as described above would initially support high intensity neutrino beams to the NOvA experiment, in parallel with at least one new 8 GeV based flavor/rare decay experiment. Depending upon future directions flexibility is retained for delivering neutrinos toward the DUSEL site and/or protons into the Tevatron. The purpose of this document is to describe an R&D plan that would position the U.S. to initiate construction of Project X in the 2012 time frame, assuming a go ahead decision in roughly 2010. The organization of this document is as follows: (1) Goals - Describes goals of the R&D and preliminary design period (2008-2011). Included are design, technical development, project documentation, and organizational goals. These are described in the context of an overall set of performance goals for Project X. (2) R&D Plan Elements - Describes the essential technical elements of the plan, including major subsystem performance requirements, associated accelerator and technology issues, and the plans for addressing these issues. (3) R&D Plan - Describes how the plan elements are assembled into a time-ordered plan, defines the associated resources required to support this plan, and describes the alignment of activities undertaken within the Project X, SRF/ILC, and HINS programs. Also describes how the R&D plan will be organized and executed by the prospective participating institutions.