Fermilab Steering Group Report

Chapter 5
Facilities for the
Intensity Frontier

Project X and the ILC

Among the proton facilities that the Steering Group considered, Project X is unique in supporting ILC development at Fermilab. It would drive the initial stage of industrialization of cryomodules and provide experience with operating the linac as a system, advancing the ILC if a delay in a decision to construct slowed progress in industrialization.


The superconducting radio-frequency cryomodules are the most complex and expensive technical element of the ILC. Development of the national and institutional capability to build and test cryomodules with ILC specifications is a high priority of the GDE Americas Regional Team and of Fermilab in its bid to host the ILC. The DESY experience has shown that mastery of this technology requires significant infrastructure investments and a long learning curve for personnel.

Project X requires approximately 33 ILC-style cryomodules. In the current design, nine are "ILC-like" and 24 are "ILC-identical." These cryomodules provide acceleration between 1.0 and 8.0 GeV. Production over a three-year period represents a significant advance over currently anticipated capabilities. However, such a production rate is below ILC requirements, so Project X would represent the initial phase of industrialization for ILC in the U.S. Full integration within an ILC industrialization plan requires more study.

Operational experience and systems testing

Project X could be configured to use the same beam parameters as the ILC (9 mA×1 ms ×5 Hz). The linac design calls for 31.5 MV/m but could operate successfully at lower gradients. The RF generation and distribution system would be the same as the ILC's, giving valuable experience with the klystrons, modulators, couplers, and cryomodules under operational conditions. The focusing arrangement, i.e. distribution of quadrupoles through the cryomodules, is somewhat different from the ILC's between 1 GeV and 5 GeV.

Operation of the linac with electrons is also under study. It would require a mechanism to provide appropriate phasing of the cavities to compensate for the fully relativistic state of the electrons. Ferrite-based vector modulators, currently under development, could provide this capability. Operation with electrons at the full ILC specification would provide important understanding of higher-order modes and associated loads on the cryogenic system.

Test beam for detector development

Project X would substantially increase the capabilities of the 120 GeV test-beam program and would support the laboratory's test-beam infrastructure through the construction of new beamlines driven by the 8 GeV linac. These new test beams could provide 8 GeV protons and electrons with the exact ILC beam-time structure, of interest to the ILC detector community for evaluation of readout strategies and low-energy calorimeter performance.