Group III Accelerator Systems Consultants K Oide M

Group III Accelerator Systems Consultants: K. Oide, M. White F. Willeke, Presenters: Seryi, Palmer, Kuchler, Carwardine, Brachmann, Larsen Summary Covered Areas: General Comments, DR, BDS, Main Linac Design, Particle Sources, Civil Construction

Finding: • Committee observed a fairly coherent program to arrive at a more detailed and comprehensive ILC design until 2012 • ILC Program Funding national/International is not completely restored • Original Goals for Technical Design have been reduced Comment: • Committee interprets the Goals of the ART program as “Demonstrate the feasibility of critical Systems in an R&D-like fashion to the level of conceptual/preliminary design to make sure there are no technical surprises and to arrive at an improved cost estimate” • This is a reasonable and adequate goal given the constraints and boundary conditions of limited funding • The Committee believes that available resources including the nondedicated-ILC resources are not sufficient to make progress to achieve the reduced Technical Design Phase goals

Finding The dedicated ILC effort is complemented by synergetic efforts in collaborations which are partially supported by other programs making best use of synergies such as generic linear collider studies, CLIC, Project X, Light-sources, CEBAF 12 Ge. V upgrade, SBIR programs Comment: The committee applauds to the ingenious and persistent way the ILC funding crisis is handled by the laboratory management and staff. Recommendation: The pursued strategy of the laboratories to use complementary resources to achieve as much as possible of the Technical Design goal with limited dedicated funding, is strongly endorsed by the committee

Finding: The ART program pursued in the areas under consideration is very broad Comment: Funding is too tight to cover all the topics adequately In the short time available committee could not see much opportunity for prioritization and a strengthening of the most critical areas Recommendation: The teams should revisit the scope very carefully and try to identify opportunities for prioritization and redirection of resources to make sure that the most urgent and critical items achieve an optimum amount of support. All “pet” projects - if any- should be deemphasized if there is a chance to redirect the sources to other critical areas This effort should be be pursued in a bottoms up fashion

Comment: The credibility of the ILC effort has suffered greatly from the funding crisis, individual with important and unique expertise have left the ILC effort or have been redirected to other projects Recommendation: Funding agencies and laboratory management should provide a clear perspective and a clear commitment to the near term and medium term goals which would bring the ILC project close to a decision

Civil Construction, Accelerator Tunnel and Site Concept Findings: Civil construction issues are carried forward with a minimum of support and funding The efforts concentrate on detailing the baseline design Limited effort is used to pursue alternative site and tunnel solutions Comment: The committee is disappointed that few resources have been made available to thoroughly explore the potential cost benefit of a completely alternative site concept considering • Cut and Cover Tunneling techniques • Minimum Accelerator Site • Remote site, on surface utilities • Single Tunnel solution

Recommendation Given the importance of ILC cost reduction, the potential of saving substantial amount of cost by going to an alternative site concept should be seriously considered in a truly quantitative way and should be made independent from individual laboratory interests The necessary resources should either com from a redirections or from additional funding sources

BDS Findings • Broad scope; connects ILC to the experimental community; work with detector on interfaces, parameter space, push pull, etc; • ATF 2 – limited US effort with high impact, very well embedded into international ILC community effort, provides training to newcomers from peripheral communities • Important issues addressed: beam dynamics in final focus; feedback and stabilization issues; • Limited effort for BDS system engineering design and system integration to assure system coherencies, identify and eliminate undesired interference • Next iteration on cost, risk, critical elements, prototyping, … may not need detailed sys design; • Several very interesting R&D work such as crystal collimation generated by non. ILC resources and provides valuable input Comment: Despite its diversity, BDS efforts appear to be well focused and optimized in terms of limited funding Recommendation: • The early effort on machine detector integration is considered very much necessary and is strongly endorsed • Increased ressources for engineering, integration and prototyping in the BDS should be seriously considered by ART management and funding agencies

Main Linac Dynamics / FLASH • FNAL and KEK efforts were delayed and/or reprioritized, thus FLASH is the only operating SRF lepton linac in the world, and the only place machine studies can be carried out to understand real RF overhead requirements, beam loading, running close to quench, Lorentz Force Detuning, beam stability, etc. for anything like an ILC machine. • DESY management has been extremely supportive of ILC and some dedicated FLASH scientific user beam time is allowed to be dedicated to ILC studies. • A vacuum leak in FLASH was the probable result of beam loss during high-current running for ILC. Loss detectors are being implemented; • FLASH is operated more or less manually; there is inadequate effort to write applications. • This is a very small effort, with a minimal budget. • Funds are well spent and should be augmented if possible to ensure confidence in the eventual design parameters.

Main Linac Dynamics / FLASH – Recommendations • Consider collaborating with SNS to get mutuallybeneficial answers to questions of reliability and radiation damage to piezos and other components in the linac. • More effort devoted to automated control of FLASH would be useful to ILC and DESY; ILC applications developers could gain expertise and FLASH could be run more efficiently for users.

electron/ positron source • r&d on the source drive laser system and photocathode is being carried out at SLAC to answer questions about stability and feasibility of the laser itself and the ability to reliably generate long bunch trains from the photocathode. • The SLAC gun lab has a gun that’s similar to ILC specs and a laser that makes 2000 pulses in a 1 -ms-long train • No existing photocathode meets ILC requirements; • Ongoing collaboration with JLAB takes advantage of gun r&d in support of JLAB’s programmatic needs, and helps fill the gap where SLAC has no time. • Additional funding from SBIR was very helpful. • Worldwide work on polarized electron sources is minimal • Concern about the positron source - who is leading it and are they working on the ILC design…

electron/ positron source Recommendations • SLAC eventually plans to collaborate with CLIC on the laser - should be implemented when practical • Consider collaboration with SNS on liquid target issues

Cesr. TA / DR • • • Studies electron cloud formation and suppression with the beam and field conditions similar to ILC. Various diagnositic / mitigation devices are installed, incl. RFA, XBSM, electrostatic suppression, grooves, various coatings, etc. Observe EC instability with a very small vertical emittance, both coherent and incoherent effects. Compare with simulations and validate extrapolation to ILC. Verify low emittance tuning techniques. Already reconfigured Cesr ring to the DR mode. RFAs, XBSM, and beam pipes with various configuration have been installed. Observed coherent tune shift due to EC, which was consistent with simulation. Achieved about 40 pm vert. emittance. It is essential to achieve the ever smallest vertical emittance e+ beam. Continue to develop LET, especially in suppressing the vertical dispersion. Complete the program by 2010 as planned to contribute the decision of the DR design.

Cesr. TA / DR • Besides the highlighted topics, it is not clear that design and engineering works have done or even started for the damping ring, esp. in more or less conventional components such as magnets, rf, diagnostics, injection, civil, etc. This can be one of the results of the budget crisis. • The cost estimation in RDR has to be reviewed wrt. the engineering work, otherwise there may be a risk of cost overrun, as DR is not a small system. • It is important to reserve these experienced people for such design effort after the completion of Cesr. TA.

2009 ART review: Management-Findings • The ART Team has managed to survive the FY 2008 budgetary crisis, as well as the FY 2009 continuing resolution. • The ART program is restarting consistent with the planned $35 M FY 2009 budget. Some aspects of the restart, notably staffing, have been impacted by the FY 2009 CR and the inability to add staff, but ART Management and the various Laboratories are now addressing these issues. • ART, working with GDE guidance, has selected a set of R&D efforts consistent with a significant US participation in any ILC program.

2009 ART review: Management-Comments • The following ILC activities are being supported by ART for future leading roles by U. S. SRF, rf units, controls, klystrons, LLRF, distribution, etc. (Other regions similar probably. Plug compatibility. ) Beam delivery system with UK. Other areas – electron source, possibly RTML, NOT positrons, damping rings

2009 ART review: Management-Comments • The $35 M budget for FY 2009 and similar amounts to FY 2012 resulted in some reduced effort compared with planning for FY 2008 prior to the Omnibus Bill and work stoppage. All engineering was removed. Reduced number of cavities, reduced string test. Manpower lower. Slow recovery of critical personnel. • Some work could be added if increased resources were available.

The ART Program – Comments -The Committee Charge • • • the quality and structure of the organization and management of the program Very good the scientific and technical merit of the R&D plan Well matched to funding and resources the achievements in the past twelve months Good restart of program feasibility of the milestones for FY 2009 and FY 2010, and Ambitious but possible the match between funding and manpower requirements and the availability of these resources in FY 2009 and FY 2010 Staffing is a concern; must be monitored

The ART Program – The explicit Committee Charge • Is the program well integrated managerially and technically into the GDE Technical Design Phase (TDP)? Is the R&D program well integrated into the TDP? ART program personnel are playing active roles in both GDE management and technical areas. If anything we are slightly over represented. The ART program elements and associated goals were developed in partnership with the GDE TDP program Agree • Has management instituted effective mechanisms to ensure the goals of the TDP are met? An R&D program such as ART is inherently more flexible than a construction project. As such, the detailed milestones are developed on a annual basis within the overall rubric of the GDE TDP phase and resources evolve accordingly. In this way we formally monitor progress and react to technical events. Lab management plays a crucial role in this process. Agree

The ART Program – The explicit Committee Charge • Has the coordination of the national R&D plan with the individual laboratories been effective? The mechanisms to do this are certainly in place and have been described in the management talks. Effective is presumably in the eye of the beholder but a good example of this process is the recent re-planning engendered by the ARRA program which, while we have not dwelt on it’s impact, was a significant factor during the past few months. Management is a dynamic process. The synergistic development of the program is impressive.

The ART Program – The explicit Committee Charge • has the program efficiently recovered from the sudden reduction in funding due to the fiscal year 2008 appropriation for DOE High Energy Physics? Are there further steps to be taken? The program will not ‘recover’ from the programmatic decision to reduce the annual funding from $60 M + to $35 M/yr. We are close to reestablishing our manpower to the lower profile (~100 FTE’s). We have not completely recovered yet however and some additional personnel are still necessary. Lab management is working on this but the CR was an impediment and hiring time constants are several months. This analysis is reasonable. • Does the R&D plan ensure the U. S. will have a leading role in the ILC program? Any future role of the US in the ILC is of course a policy decision for the wider community. I think it’s fair to say that the ART R&D program is consistent with the US playing a leading role should it so choose to do. We agree.

The ART Program – The explicit Committee Charge • What are the broader impacts of the program? The ART program has synergies at several levels. The most obvious is with Project X at Fermilab and we have described this. At a less specific level we consciously strive to build upon the national lab interests and strengths (leverage). Possibly the most obvious example is JLAB and SRF development but it is true at ALL of the labs and MOST of the program elements. At the most generic level ART provides support for the linear collider school, LCWS meetings, and community communications The ART program as restarted in FY 2009 is indeed synergistic and consistent with a dynamic program in the future while maximizing R&D support for the ILC.

Recommendations • • Continue the Program as outlined for the Review, especially emphasizing the synergistic aspects to amplify the return. Monitor the ability of the major laboratories to provide the necessary staffing for the agreed work elements. Utilize any extra funding streams as efficiently and quickly as possible. Work with the Department of Energy and NSF to incorporate annual inflationary adjustments into the budgeting planning. Work with the NSF and Department of Energy to plan work for 2013 and later out years assuming the necessity to complete additional design work, and to provide a smooth transition to the start of project engineering. Monitor the funding requirements for CFS support given the increased demands on in-house staff at Fermilab resulting from additional funding in FY 2009. The NSF and DOE should consider the possibility increasing ART support so that supporting positron source definition could be added without detriment to the rest of the defined program.

Positron • Findings – – – • US is active almost all fields of the ILC except the positron source which dropped out since Black December. Right now the US activity is limited to simulation works at LLNL (target), Cornell (Lithium lens) and ANL (target). There are still some critical issues in the ILC baseline design that require further R&D, such as the gradient, electron cloud etc. Among them the item that has not been emphasized much is the positron source. The present baseline contains several problems. UK has been playing the central role in this field but its future activity is not transparent since the same time. Japan is trying to increase the activity in this field but this is limited by the quality of manpower. US has the highest expertise in this field, but presently its contribution is limited to simulation studies. Recommendation From the view of entire GDE plan US should enforce its activity in the hardware of the positron source. The required budget is not much compared with the SRF development. Re-assignment of manpower from the accelerator systems (such as DR after CESRTA) is desirable.