Requests of Future HEP e+/e-Facilities Tor Raubenheimer FACET2 Workshop October 15, 2015

Critical Requirements for HEP facility Outline Critical Requirements for HEP facility Energy Luminosity Cost Credibility (laugh-factor) Other issues: Polarization, Lum. Spectrum, Stability, Operability, … FACET2 Workshop, October 14, 2015

Dictated by the physics Energy and Luminosity Dictated by the physics In general, L scaling as E2 is required however some situations may reduce this (e.g. studying known resonance) 10,000 events/yr  1x1034 at 1 TeV, 2.5x1035 at 5 TeV Possible scenarios 500 GeV cms ILC is constructed Afterburner on ILC for 1 TeV cms Addition facility upgrades (PWFA-LC) to 3 ~ 5 TeV ILC too expensive and FCC not pursued Start with 1 TeV PWFA-LC FACET2 Workshop, October 14, 2015

Linear Collider Luminosity Luminosity is critical in a linear collider Physics studies have been based on ~1x1034 cm-2sec-1 Need large beam powers, large bunch charges, and small spot sizes For example, at 1 TeV: 20 MW beam power, 1010 e+/e- per bunch, frep = 10 kHz, and sx/sy = 140 / 3 nm  1x1034 cm-2sec-1 within 1% of cms energy Maintaining E2 scaling very challenging All parameters pushed beyond state-of-the-art Choose set that minimizes the pain! FACET2 Workshop, October 14, 2015

Luminosity Proportional to (Pbeam / sy) * (N / sx) but latter factor has strong impact on luminosity spectrum  Maximize (Pbeam / sy) Getting multi-MW beam power requires large amounts of AC power with both cost and environmental impact  Need efficient transfer from AC  Beam Minimizing spot sizes requires small emittances, strong focusing, and high stability  Flat beam emittance preservation and stability FACET2 Workshop, October 14, 2015

Implications for the FACET/FACET2 program Emittance preservation still needs study/demonstration Further demonstration of drive/witness acceleration with high efficiency and witness low energy spread Understand and demonstrate high-h positron acceleration Demonstrate stable operation Understand multi-bunch stability and plasma heating Design studies are needed to illustrate feasibility for parameters beyond those accessible at FACET2 FACET2 Workshop, October 14, 2015

Credibility and Feasibility Plasma collider huge undertaking that will require engagement of the HEP and Accelerator communities By the end of FACET2 I think we should have reasonable answers to questions posed by reasonable people and not just cartoons Tolerances, plasma stability, heat dissipation, drive beam merge/separation, cost-scale, … A reasonable demonstration pathway, e.g. PWFA-FEL ? FACET2 Workshop, October 14, 2015

FACET R&D Program from FACET proposal to DOE, July 2008 FACET2 Workshop, October 14, 2015

My References ILC Reference Design PWFALC: AAC’08: AAC’04: A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV, J.P. Delahaye, et al. (2014). ⁞ A Conceptual PWFA Linear Collider, C. Adolphsen, et al. (2009). AAC’08: R&D for Very high Energy Colliders, T.O. Raubenheimer (2008). Design considerations for a Laser-Plasma collider, C. Schroeder, et al. (2008). AAC’04: An Afterburner at the ILC: The Collider Viewpoint, T.O. Raubenheimer (2004). Advanced Accelerator System Requirements for Future Linear Colliders, G. Dugan (2004). FACET2 Workshop, October 14, 2015

Summary Huge opportunity to define ‘conceptual’ PWFA-LC Both systematic experimental studies and design Show significant cost benefit of new technology 1st focus should be on emittance preservation Critical for any application (LC, FEL, high brightness source, …) 2nd priority on narrow spectrum and then high efficiency Spectrum also applicable to any application Efficiency necessary for large applications such as LC 3rd priority positron acceleration Necessary for LC applications In parallel, need to prioritize pre-conceptual design Too many hand-waving answers to engage realistic people FACET2 Workshop, October 14, 2015

FACET2 Workshop, October 14, 2015

Future Facility Costs The energy and luminosity requirements for future colliders are severe Constituent energy ~1 TeV and luminosity >1x1034 cm-2s-1 Achieving these parameters will be expensive There is some cost scale that decreases the probably of approval Crude model comparing projects in 2020$ ILC estimate from Mike Harrison at FNAL P5 meeting SSC value of 10B$ to be completed in 1996 (seemed OK) Estimated construction costs in FY2020 $ All costs escalated to 2020$ using 3.5% FACET2 Workshop, October 14, 2015

Linear Collider Cost Drivers ILC costs provide basis for optimization 60% of costs are in ML 15% in the long RTML, and 7 km damping rings Power handling ~5% Detector and IR Hall add another ~10% ILC Costs by Sub-system (from RDR) FACET2 Workshop, October 14, 2015

Facility Cost Goals Goal: reduce LC cost by an order of magnitude – tough! Can benefit from optimization all subsystems New acceleration systems Improved focusing concepts Improved beam generation Facility costs scale roughly with power consumption and facility size High gradient can reduce site length – are components cheaper? Improved efficiency, better sources, or improved focusing can reduce power consumption All DOE projects must optimize life cycle costs Inflated annual energy costs ~1$ (2020$) per Watt Energy costs an order of magnitude smaller than capital cost in ILC design  important factor in a future design FACET2 Workshop, October 14, 2015