Director's Corner

GDE position paper on post-TDR

| 13 October 2011

Timeline projection for a linear collider programme beyond the fulfillment of the GDE mandate

The Global Design Effort (GDE) will complete the final deliverable in our mandate with the completion of the Technical Design Report (TDR). We intend to submit the TDR at the end of 2012, and with reviews and approval of the report, including required revisions, we expect our present task to be completed by about mid-2013. As I discussed last week regarding the Large Hadron Collider results, this is expected to be too early to seriously propose a linear collider to governments. Therefore, this raises the question of what should come after the TDR.

The International Linear Collider Steering Committee (ILCSC), chaired by Jon Bagger, is taking the lead in developing a post-TDR linear collider plan. The post-TDR plan was the central topic discussed at their last meeting at the Lepton Photon 2011 conference in Mumbai, India in August.

As input for that process, the GDE Executive Committee created a short position paper in which we discuss proposed goals of a continuing ILC R&D programme that will continue to move the ILC forward, as well as organisational issues for the successor to the GDE, addressing what primary GDE assets should be preserved and what areas could be improved. I will report on the outcomes of the ILCSC plan in this column as they emerge. In the meantime, I think it is fair to say that all agree that a GDE-like subtask (with a substantial overlap of key GDE people) will be part of the new organisational structure that will carry out the continuation of the work towards a linear collider.

I share our GDE position paper in its entirety below:


To: Jon Bagger, ILCSC Chair

From: Barry Barish for the GDE Executive Committee

Subject: GDE position paper on replacing the GDE management in the post-2012 ILC era

With the publication of the Technical Design Report in 2012, the ILC will be ready to proceed with engineering design and project preparation tasks for the construction of a 500 GeV center-of-mass energy linear collider. In addition, the design presented will have the ability to meet the physics requirements at lower energies, and the report will address the options for increasing the energy reach of the ILC cost effectively toward 1 TeV. Finally, we will present an up to date costing and a discussion of planning for project implementation.

The next step toward ILC realization will then belong to the global high energy physics community who will need to recommend construction, informed by LHC results. Although the excellent performance of the LHC and detectors are very encouraging, time will be required to prepare the recommendations, and to await government actions. During this period, the global ILC GDE core accelerator and technology team needs to remain intact and continue development of the project in collaboration with the physics community which will propose the linear collider. We propose this interim period be for a nominal three years, by which time much should be clarified regarding whether and in what form the ILC should go forward.

During this interim period, likely to last several years, ILC-project oriented accelerator and technology R&D will continue. The joint work with CLIC will continue and should be strengthened in areas of joint interest. As it has in the past, ILC R&D will continue to benefit projects having significant technical or design overlaps, such as the European XFEL, the super B-factories, Project X, JLab and SNS upgrades, etc. The ILC project team will continue its partnership with the development efforts of these new projects, insuring that we take advantage of their results and new knowledge, and adapt them to the ILC design as needed.

With all of this in mind, the two primary missions of the post-2012 team will be:

1) Accelerator Design and Integration (with physics and detector groups)

The AD & I team mission will be to further develop the machine design, including a) incorporating results of new R and D, b) development of options for running at other energies, and c) analyzing specific siting choices.

The team objectives include evaluating and producing cost and power consumption-optimized designs for a linear collider over a range of energy and luminosity, (including a design and plan to upgrade towards 1 TeV), and to partner with the civil engineering effort to develop specific sites and to address site-specific design issues. The work may also include studies of gamma-gamma and giga-Z options.

2) Coordination of R&D on improving the performance and reducing the cost of the SCRF systems.

The R&D coordination effort will deploy the SRF linac test facilities to carry out value engineering aimed at reducing the remaining cost risk and pursuing high-gradient development for the ~1 TeV extension of ILC. The ILC SRF team will extend industrialization studies started during the TDP. As was done for the TDR, the central team will coordinate this activity worldwide with the goal of building significant fractions of the main linac components in all three regions of the world.

To coordinate the activities described above in 1) and 2) some important features of the GDE management and team will need to be preserved. These include:

  • Maintaining the ‘core competencies’ that have been developed in the key areas of the ILC machine design and R&D programs. This is absolutely essential; these individuals must remain actively involved, in order to maintain and update a ‘live’ design for the ILC and to move the program forward.
  • An ILC director will be essential for the next phase, in order to provide overall intellectual and project leadership for the ongoing efforts, and to represent the interests of the ILC programs worldwide. Whether there should be a single director for both the accelerator and detector programs depends on how the two activities are brought closer together.
  • The equivalent of the GDE Regional Directors will be necessary. The role of the Regional Directors has been different in the three regions for the GDE, but in general, this coordination role needs to be strengthened as we foresee moving toward a global project. Duties will depend on the region, but include resource coordination, helping to reconcile laboratories’ and ILC’s priorities and programs within each participating laboratory, as well as organizing regional and regionally hosted meetings etc.
  • The equivalent of the Project Managers or their function will be necessary, in order to coordinate the ongoing technical program described above, following global priorities and maintaining coherence in the distributed efforts.
  • Functionally, the GDE management has been able to effectively lead the ILC design and R&D effort, make technical decisions and set priorities that have been accepted worldwide, leading to a unified global effort and design. It is essential that this ability be maintained in a global ILC project.
  • Functionally, the GDE management has been able to organize the ILC efforts with sufficient autonomy from the laboratory and agency programs and priorities to move the effort forward, meet deadlines, etc, while at the same time understanding and working with the labs and their priorities. A reasonable level of autonomy must be preserved to insure the program can move forward.
  • The small GDE common fund has enabled flexibility to run the program, supporting some global efforts like costing, electronic data bases, publications, outreach, etc, as well as to mitigate funding problems that develop locally, and to support international committees, etc. The present level for the GDE is ~ 1 M$/yr; it would be prudent to envisage maintaining this at the current level until it is clearer how future ILC effort will be organized and structured.

Experience with the GDE organization during the past five years has indicated some weaknesses which may be able to be remedied in a future organization. These include:

  • The “virtual” nature of the GDE, while essential to be able to make use of the expertise distributed around the world, results in a certain degree of inefficiency. Drawing on the experience of international corporations with world-wide distributed activities, it might be possible to design an organization specifically structured to minimize this inefficiency. In contrast, we believe that during the interim period it may be too early to create a host laboratory, as desirable as that will be as soon as the ILC nears construction. We are also concerned that the post-2012 management retain sufficient autonomy from the host laboratory priorities to carry out its global responsibility.
  • The independent experimental and accelerator organizations for ILC design and R&D has caused continual issues, despite the many efforts to improve communications, hold joint meetings, etc. At some level, these efforts should be better integrated.
  • The independence of ILC and CLIC programs (although improving) has caused problems and duplication of effort. For the next period, it will also make comparisons difficult. Further steps to bring these efforts closer together will benefit the worldwide efforts toward a linear collider.
  • The general lack of access to CERN resources for the global ILC/GDE efforts has been a difficulty, especially where specialized expertise and experience are needed, and more specifically, it has hampered the European contributions toward the ILC. A further integration of CLIC and ILC efforts under a Linear Collider heading will help significantly in this respect, but CERN support will be important also in very specific ILC technology areas and implementation studies. Involving CERN more during the interim stage will be crucial to a viable European role.
  • In managing and coordinating the technical efforts, the GDE has relied on informal agreements with HEP Laboratories, even on major R&D programs. Moving toward a more formal work package system in the next period would facilitate setting and maintaining priorities and meeting critical schedules.

The final deliverable for the GDE will be the TDR, which we plan to complete at the end of 2012. The team will need to remain in place through a period following that for two main reasons: 1) to represent the TDR design for independent (and possibly agency) reviews of the technical design, as well as for cost reviews and to facilitate translations to local costing systems. Following these reviews, the GDE will need to finalize the TDR; and 2) a reasonable overlap period with the new interim ILC organization will be required, while the new organization becomes established and can assume control of the program. We believe a period of 6-12 months following TDR submission will be required before the transition is completed.

Overall, we believe an ongoing and viable follow-on ILC program can be achieved with reduced resources and a new organization having the above functionality; however it will continue to be very difficult to substantially update and improve the design without increasing the resources, especially engineering resources. In other words, it will require more, not less, resources to move the project closer to being construction ready. It is essential that the post-2012 organization be created and become functional as soon as possible following the submission of the TDR, in order to not lose momentum toward the ILC.

Barry Barish

Barry Barish is the winner of the 2017 Nobel Prize in Physics. He is Distinguished Professor at the University of California, Riverside and Linde Professor, Emeritus at the California Institute of Technology (Caltech). From 2005 to 2013 he was Director of the Global Design Effort and, apart from leading the collaboration to the publication of the ILC's Technical Design Report, contributed more than 300 Director's Corners in the ILC Newsline.
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