1. ANAR2017 Advanced and Novel Accelerators for
High Energy Physics Roadmap
Workshop 2017
April 2017, CERN BE Auditorium

2. Organised at the initiative of the ICFA panel for Advanced and Novel Accelerators
Organizing Committee (OC)
ICFA Panel members
Brigitte Cros (chair), CNRS- U PSud, France
Patric Muggli, MPP, Germany
Bruce Carlsten, LANL, USA
Massimo Ferrario, INFN, Italy
Brian Foster, U Hamburg, Oxford, DESY, Germany
Ryoichi Hajima, NIQRST, Japan
Dino Jaroszynski, U Strathclyde, UK
Philippe Piot, NI U (USA), Fermi Lab.
James Rosenweig, UCLA, USA
Carl Schroeder, LBNL, USA
Chuanxiang Tang, Tsinghua U, China
Mitsuru Uesaka, U Tokyo, Japan
Mitsuhiro Yoshida, KEK, Japan
Other members
Ralph Assmann, DESY, Germany
Edda Gschwendtner , CERN, Switzerland
Bernhard Holzer, CERN, Switzerland
Sponsored by

3. Goal of the workshop
To define an international roadmap towards colliders based on advanced accelerator concepts, including intermediate milestones, and to discuss the needs for international coordination.

4. Outline Scientific frame Challenges and global roadmap items
e- e+ Collider for HEP
4 concepts (WG), status & proposed roadmaps
Challenges and global roadmap items
Review of strategy worldwide
Next steps toward a collider roadmap

5. Challenging question for the community of ANA
Can we envisage the delivery of an Advanced linear collider at >1TeV (10 TeV) in 2035?
Electron- positron Collider
Parameters defined for/by HEP (Luminosity)
Four different concepts of Advanced Accelerators were discussed

6. Advanced Accelerator concepts discussed in 4WGs
At this workshop
Wakefields driven in plasma by intense laser beams : LWFA
Wakefields driven in plasma by particle beams: PWFA
Wakefields driven in dielectric tubes by particle beams: DWA
Wakefields driven in dielectric structures by short-pulse lasers: DLA

7. Status/roadmap LWFA
Excellent status from Mike Downer, and comparison of 4 concepts
WG LWFA coordinators : Arnd Specka (CNRS), Dan Gordon (NRL), Carl Schroeder (LBNL)

8. Normalized Trans-verse emittance Repetition Rate & Repeatability
Current Status of LWFA Electron Bunch Properties
M. Downer intro talk ANAR2017
Property
State of Art*
Reference
Remarks
Energy
2 GeV (± 5%, 0.1 nC)
3 GeV (±15%, ~0.05 nC)
4 GeV (±5%, nC)
Wang (2013) - Texas
Kim (2013) – GIST
Leemans (2014) - LBNL
Accelerates
from E ≈ 0
Energy Spread
1% .01 nC, 0.2 GeV)
5-10%
Rechatin (2009a) – LOA more typical, many results
0.1% desirable for FELs & colliders
Normalized Trans-verse emittance
~ 0.1 π mm-mrad
Geddes (2008) - LBNL
Brunetti (2010) - Strathclyde
Plateau (2012) - LBNL
Measurements at resolution limit
Bunch Duration
~ few fs
Kaluza (2010) – Jena (Faraday)
Lundh (2011) – LOA; Heigoldt (2015) – MPQ/Oxford (OTR)
Zhang (2016) – Tsinghua
Charge
GeV ±5%
GeV ±14%
Rechatin (2009b) – LOA Couperus (2017) - HZDR
Beam-loading achieved. FOM: Q/∆E ?
Repetition Rate & Repeatability
~ 1 > 1 GeV
1 ~ 1 MeV
He – UMIch (‘15); Salehi (‘17) – UMd; Guénot (‘17) -- LOA
Limited by lasers & gas targets
• Should additional beam properties be included?
• Are the state-of-art numbers accurate?
• Have I omitted important references?
* No one achieves all of these simultaneously!
• Brunetti, PRL 105, (‘10)
• Couperus, submitted (‘17)
• Geddes, PRL 100, (‘08)
• He, Nat. Comms 6, 7156 (2015)
• Rechatin, PRL 103, (‘09b)
• Salehi, Opt. Lettt. 42, 215 (‘17)
• Wang, Nat. Comms 4, 1988 (2013)
• Zhang, PRST-AB 19, (2016)
• Heigoldt, PR-STAB 18, (‘15)
• Kaluza, PRL 105, (‘10)
• Kim, PRL 111, (2013)
• Leemans, PRL 113, (2014)
• Lundh, Nat. Phys. 7, 219 (2011)
• Rechatin, PRL 102, (2009)
Current Status of LWFA Positron Properties: no results yet
2/31

9. WG LWFA

10. Status/roadmap PWFA Status from M Hogan summary
2 roadmaps for electron/proton driven
WG PWFA coordinators : M Hogan (SLAC), Allen Caldwell (MPP), and Edda Gschwendtner (CERN)

13. Status/roadmap 3 Structure-based wakefield acceleration
Roadmap includes two general schemes
WG (DWA) or SWFA coordinators : Philippe Piot (FNAL/NIU) and Paolo Craievich (PSI)

16. Status/roadmap 4 Dielectric Laser accelerator
Overview by Simakov, conclusions from WG4
WG DLA coordinators: Joel England (SLAC), Josh McNeur (FAU Erlangen), Bruce Carlsten (LANL)

17. Status/roadmap 4
Dielectric Laser accelerator

18. Conclusions from WG4

19. M. Downer intro talk ANAR2017
LWFA and PWFA/DWA/DLA: Comparisons & Contrasts*
M. Downer intro talk ANAR2017
Property
LWFA
PWFA
DWA
DLA
Stand-alone?
(i.e. no RF accelerator)
YES NO
Energy Gain Achieved
0  4.25 GeV
20  30 GeV
40  80 GeV
smaller
much smaller
Accelerating Gradient
~1 GeV/cm
~ 0.1 GeV/cm
Dephasing Limited?
Positrons accelerated?
NOT YET
Wall-plug efficiency
10-5 1GeV ± 10%)
10-7 GeV ± 0.1%)
• Any help with completing the PWFA/DWA/DLA parts of the table is appreciated.
* Intended to highlight areas where the approaches differ, not to promote one approach
over another.
3/31

20. Challenges and global roadmap items :
20-25 Ys
Collider CDR
and
TDR
10 Ys
x10
Improved beam quality at higher energy
- Optimized e- sources
- e+ source
(concepts)
Adressing Specific challenges :
micron scales:
Apertures (DLA)
Synchro (LWFA)
average power
Stability
5 Ys
Injector, Accelerator stages with reliable parameters
- Optimize all parameters for e-
e+ acceleration
Adressing Specific challenges :
Staging
Efficiency
BDS

21. From W.Leemans talk

22. Our next tasks will be to
merge roadmaps (Scientific/ Strategic visions)
trigger /foster community interest to the topic

23. Review of strategy worldwide was discussed
The USA have a clear strategy driven by DoE
Asia is oriented towards short term application (radiation)
Europe provides incentive for coordinated strategies through funding of joint projects
National strategies are not formalized everywhere

24. Personal vision for PWA in Europe (cont’d)
Recommendation From R. Aleksan talk
Be ready to propose the construction of a user oriented accelerator in Europe in with credible site(s)
Why : to demonstrate the usability and appropriateness of PWA
to provide a clear option for States and decision makers
to be included in Roadmap such as ESFRI, PP, Light Sources…
to be included in H2020 calls of Preparatory Phases
Who : All partners interested in constructing a user-oriented facility
including at government levels
How : through EuPRAXIA, the success of which is mandatory
Engage in the preparation of a HE frontier DS proposal
Why : to (possibly) be included in Roadmap such as ESFRI, PP, Light Sources…
to be included in H2020 calls of DS in 2019
Who : All partners interested in studying a user-oriented energy frontier facility, including at government levels
How : Set up a Task Force, Down selecting technologies for a proposal!

25. Next steps toward a collider roadmap
We (OC) will chart a scientific roadmap from discussed items
Output of the workshop: report summer 2017
Towards a proposal for an advanced linear collider
A more detailed/technical document will be prepared for the European Strategy Research Group, by the end of 2018
Organisation to prepare it:
a series of workshops to discuss and finalize the roadmap is being planned (WG8 EAAC, Jan-May 2018 at JAI?, at AAC 2018?)
A study group to steer this activity has to be set-up: volonteers welcome

26. Thank you for your attention

27. From the US Strategy
The significant cost of R&D facilities strongly influences the roadmap for advanced accelerator R&D.
•Makes difficult (expensive) pursuit of multiple approaches in parallel.
•Drives early (too early?) down-selection of approaches.
•Cost strongly influenced the ARD Subpanel, which was charged to meet specific budget scenarios.
•An international AARD program, with some level of international coordination, is more capable of mounting the future facilities needed to explore multiple promising approaches.

28. Personal vision for PWA in Europe Objectives (cont’d)
PWA community should augment the R&D in a coordinated way and use the available and planned EC instruments
A European PWA R&D roadmap and strategy using the infrastructures in Europe,
i.e. What R&D should be done, who does it and where…
PWA should be visible at the EC level, not only for getting some funds, but also to gain credibility
PWA should use the EC tools as lever arms for getting additional national funding,