The International Linear Collider
A European Perspective
Prepared by: Philip Bambade1 , Ties Behnke2 , Mikael Berggren2 , Ivanka Bozovic-Jelisavcic3 , Philip
Burrows4 , Massimo Caccia5 , Paul Colas6 , Gerald Eigen7 , Lyn Evans8 , Angeles Faus-Golfe1 , Brian
Foster2,4 , Juan Fuster9 , Frank Gaede2 , Christophe Grojean2 , Marek Idzik10 , Andrea Jeremie11 , Tadeusz
Lesiak12 , Aharon Levy13 , Benno List2 , Jenny List2 , Joachim Mnich2 , Olivier Napoly6 , Carlo Pagani14 ,
Roman Poeschl1 , Francois Richard1 , Aidan Robson15 , Thomas Schoerner-Sadenius2 , Marcel Stanitzki2 ,
Steinar Stapnes8 , Maksym Titov6 , Marcel Vos9 , Nicholas Walker2 , Hans Weise2 , Marc Winter16 .
1
arXiv:1901.09825v1 [hep-ex] 28 Jan 2019
5
LAL-Orsay/CNRS, 2 DESY, 3 INN VINCA, Belgrade, 4 Oxford U.,
U. Insubria, 6 CEA/Irfu, U. Paris-Saclay, 7 U. Bergen, 8 CERN, 9 IFIC,
U. Valencia-CSIC, 10 AGH, Kraków, 11 LAPP/CNRS, 12 IFJPAN,
Kraków, 13 Tel Aviv U., 14 INFN, 15 U. Glasgow, 16 IPHC/CNRS.
(Dated: January 29, 2019)
Abstract
The International Linear Collider (ILC) being proposed in Japan is an electron-positron linear
collider with an initial energy of 250 GeV. The ILC accelerator is based on the technology of superconducting radio-frequency cavities. This technology has reached a mature stage in the European
XFEL project and is now widely used.
The ILC will start by measuring the Higgs properties, providing high-precision and modelindependent determinations of its parameters. The ILC at 250 GeV will also search for direct
new physics in exotic Higgs decays and in pair-production of weakly interacting particles. The
use of polarised electron and positron beams opens new capabilities and scenarios that add to the
physics reach. The ILC can be upgraded to higher energy, enabling precision studies of the top
quark and measurement of the top Yukawa coupling and the Higgs self-coupling.
The international - including European - interest for the project is very strong. Europe has
participated in the ILC project since its early conception and plays a major role in its present
development covering most of its scientific and technological aspects: physics studies, accelerator
and detectors. The potential for a wide participation of European groups and laboratories is thus
high, including important opportunities for European industry.
Following decades of technical development, R&D, and design optimisation, the project is ready
for construction and the European particle physics community, technological centers and industry
are prepared to participate in this challenging endeavour.
Supporting documents web page:
https://ilchome.web.cern.ch/content/ilc-european-strategy-document
Contact persons: James Brau (jimbrau@uoregon.edu), Juan Fuster(Juan.Fuster@ific.uv.es), Steinar Stapnes
(Steinar.Stapnes@cern.ch)
I.
2031-32, the European groups will naturally be involved
in the commissioning of both the accelerator and detectors.
This document first reports the European expertise
and track-record relating to the accelerator in section II.
Section III describes the detectors and computing. Following this, a short discussion summarises the current
political situation, suggests how a European contribution might be organised, including the contribution from
European industry and finally draws some conclusions.
INTRODUCTION
The International Linear Collider (ILC) is proposed
as an e+ e− linear collider that can start operating at
250 GeV centre-of-mass energy. The physics case, technological readiness and political opportunities of the ILC
are discussed in detail in the document: The International Collider. A global project [1] which is presented to
the European strategy update process. The international
support for the ILC is very large and Europe has strongly
participated since the early stages of the project at the
beginning of this century. The collider design and detector concepts are thus the result of nearly twenty years
of R&D. The heart of the ILC accelerator, the superconducting cavities, is based on pioneering work of the
TESLA Collaboration. This technology is the basis for
a number of operating free-electron-laser facilities (European XFEL at DESY), under construction (LCLS-II at
SLAC) or in preparation (SHINE in Shanghai).
This document complements [1] and discusses the European expertise on the ILC project for both the accelerator and the detectors. The document is based on
the report [2] that was produced by the E-JADE Marie
Curie project [3]. Possible European contributions to the
preparation and construction phases are presented. It is
based on the assumption that the ILC will be realised in
Japan with strong international participation. It is proposed that CERN will play a leading role in the European
participation in the ILC, along the lines described in the
conclusions of the 2013 Update of the European Strategy, and also in a similar fashion to that developed for
the European participation in the US neutrino program.
This report uses the same steps and timelines as the
KEK ILC action plan [4]. The ILC Preparation Phase,
currently foreseen for 2019/20-2022/23, needs to be initiated by a positive statement from the Japanese government about hosting the ILC, followed by a European
strategy update that ranks European participation in the
ILC as a high-priority item. The Preparation Phase focuses on preparation for construction and agreement on
the definition of deliverables and their allocation to regions. The European groups will concentrate on preparations for their deliverables including working with and
preparing European industry. Europe and European scientists, as part of an international project team, will also
participate in the overall finalisation of the design, while
in parallel contributing to the work of setting up the overall structure and governance of the ILC project and of
the associated laboratory. The Construction Phase
will start after the ILC laboratory has been established
as an organisation, currently foreseen from 2023/24, and
intergovernmental agreements are in place. At the current stage, only the existing capabilities of the European
groups relevant for this phase can be outlined in broad
terms. As mentioned above, the detailed contributions
will have to be defined during the preparation phase and
formalised by inter-governmental agreements. With the
completion of the foreseen 8-9 year construction phase in
II.
ACCELERATOR
Europe has a very strong scientific, technological and
industrial basis with which to make significant contributions to the construction of virtually any part of the
ILC accelerator. In the following three subsections, the
past and current activities, the ILC Preparation Phase
and the subsequent Construction Phase will be described,
from the perspective of European capabilities to participate in constructing the ILC accelerator. A final subsection considers the organisation of the future ILC accelerator activities on the European side.
A.
ILC accelerator competence in Europe
The key recent and ongoing activities in Europe with
high relevance for ILC are the direct European participation in the ILC Global Design Effort (GDE) and
the Linear Collider Collaboration (LCC), the European XFEL (E-XFEL) project, the European Spallation
Source (ESS) superconducting linac, the European participation in the ATF-2 [5] at KEK for linear collider
studies, the E-JADE Marie Curie project [3], and the
CLIC study [6, 7]. The following paragraphs summarise
these briefly; a more comprehensive description can be
found in [2].
150
Total ADI
Total SCRF
125
FTE
100
75
50
25
0
FIG. 1. The contribution to the ILC GDE (2007-2012) in
staff years per European country, separately for SCRF and
Accelerator Design and Integration (ADI).
1
SCRF Cavities
Couplers and Tuners
Cold Vacuum
Cavity String Assembly
SC Magnets
Infrastructure
Accelerator Module Test
Facility (AMTF)
Cryogenics
Sites & Buildings
AMTF hall
ly
Po
l an
d
Ru
ssi
a
Sp
ai n
I ta
nc
an
y
Cryomodules
Fr
a
rm
Ge
Linac
e
across the linac-relevant E-XFEL work packages (including testing) are given in Table I.
During 2007-2012, the ILC GDE was responsible for
the coordination of the worldwide ILC accelerator design.
R&D and cost-estimate development during this period
culminated in the publication of the ILC Technical Design Report in 2013 [8]. The estimated European FTE
contributions (728 person years in total) during 20072012 are summarised in Figure 1, divided into accelerator domains and superconducting RF (SCRF) technology
development (excluding management and documentation
support). Note that the SCRF numbers represent ILCspecific resources and do not include the extensive synergetic contributions from the European XFEL during this
period.
After the completion of the ILC TDR [9] in 2013,
the GDE was replaced by the LCC. In spite of limited direct funding for ILC studies in Europe during the
last five years, the combined efforts in several related
projects have allowed European researchers to continue
ILC project development activities in the framework of
the LCC, in close collaboration with Japan. The most
important of these projects has been the construction
of the European XFEL (discussed in next paragraph).
The ILC activities have been to a large degree focused
on studies for implementing a 250 GeV ILC machine in
Japan. These European activities are as follows:
✦ ✦ ✦ ✦
✦
✦ ✦
✦ ✦
✦
✦
✦
✦ ✦
✦
✦
✦
✦
✦
✦ ✦
✦
TABLE I. Responsibility matrix for cryomodule production
and testing for the European XFEL. More details and a similar matrix can be found in [2] concerning construction of
SCRF modules for the ESS linac.
• Participation in the LCC ILC-related R&D (SCRF,
Cryogenics, High-Level RF (HLRF), Civil Engineering, Beam dump, Positron source, Radiation
safety)
Construction of the European XFEL is now complete,
and the SCRF linac has been brought into operation.
The E-XFEL can directly benefit the ILC in several ways:
• Participation in the ATF-2 programme at KEK
(nano-beams and final focus)
• The experience and knowledge gained during the
unprecedented industrial production of 100 cryomodules over a three-year period can provide invaluable input to any future large-scale production
for the ILC. The detailed cost breakdown of the EXFEL cryomodules provides a solid basis for any
future projection of a possible European in-kind
contribution to the ILC.
• Combined studies with CLIC in several areas
(beam-dynamics, modelling/simulation, damping
rings, Damping Ring to the Main Linac transfer
(RTML), Beam Delivery System(BDS), MachineDetector Interface (MDI), cost and power)
• E-JADE supported secondments of European researchers to Japan for ILC and ATF-2 related activities.
• The currently ongoing commissioning of the EXFEL and its future operation will provide invaluable system testing for the ILC, including understanding the ultimate performance of the modules
with beam loading, beam control (Low-level RF development), software tools, and more general operational experience.
These activities involves groups in France, Germany,
Italy, Spain, UK and CERN.
Beyond the activities listed above, the European XFEL
project at the DESY campus is the most prominent
demonstration of the European capabilities to contribute
to the construction of the ILC accelerator. The 17.5 GeV
superconducting linac at the E-XFEL comprises 97
ILC-like superconducting cryomodules, containing 776
1.3 GHz TESLA cavities driven by 25 10-MW-multibeam
klystrons. The E-XFEL linac configuration is very similar to that foreseen for the ILC and can be seen as a
7% (in beam energy) ILC prototype. The cryomodules
were produced by a consortium of six European countries together with predominantly European industries.
The consortium members and the various responsibilities
• The infrastructure that was constructed for EXFEL cavity and module testing, high-power coupler conditioning and module assembly will continue to be maintained, and (in the case of the testing infrastructure) will provide a significant support for SCRF R&D.
The expertise and infrastructures established for the
E-XFEL are now partially deployed in the construction
2
the construction and operation phase, and about a
future governance model for the ILC. These issues
are discussed in further chapters of this document.
of SCRF modules for the ESS linac. The consortium
is slightly different: Sweden and UK and several new
groups from countries already involved in the E-XFEL
have joined, while DESY is peripherally involved. The
ESS effort is also strategically important for ILC, as infrastructures and industry capabilities are being updated
and the procedures for SCRF module production are being refined.
B.
The main technical activities are summarised in table II.
ILC accelerator Preparation Phase activities in
Europe
Activities in Europe
More details
SCRF activities
Cavity fabrication and preparation, Power Couplers, Automation of assembly, E-XFEL → ILC
High efficiency klystron Reaching 70% efficiency or above
R&D
with several vendors
The overall resources needed during the four-year
Preparation Phase are estimated to be 5% of the material and 10% of the personnel foreseen for the 250 GeV
accelerator project construction [10]. Irrespective of the
final level of European investment into the ILC, it would
be appropriate that, given its expertise and previous involvement, Europe invests 1/3 of the overall effort required in the preparation phase. The remainder of this
section assumes this to be the case. This would then
amount to a total European material budget of 85 Me
and 240 FTE-years, integrated over the period [2]. Distributed over four years, an average yearly budget of
around 30 Me (covering material and personnel) would
be needed with an increasing profile from 2019 towards
2022. The resources required for the activities in the
preparation phase are hence similar in scope to those
used by existing project studies such as CLIC and FCC.
One important difference will be that the ILC preparation requires a strong engineering team, such that the
profile of the ILC personnel will be towards more engineering and technical design and will gradually become
less focused on R&D studies.
The preparation phase will be used for three main purposes:
Cryogenics system
Accelerator
Issues
LHC system similar in size to ILC
Domain Positron source, Damping Rings,
Beam Delivery Systems, Low
emittance beam transport, Beam
dumps
Detector and Physics
Design optimisation, MDI, Technical prototypes, TDR, Physics
Studies, Sodtware
Documentation system
Experience from E-XFEL
Regional Design office
Naturally at CERN, linking to
other European National Labs
TABLE II. Main technical activities during the preparation
phase.
C. ILC accelerator in-kind contributions from
Europe during the ILC Construction Phase
The actual contribution from Europe will be determined by negotiations at a later stage, and no formal
commitments can be made at this time. The models
chosen for in-kind contributions in this document, and
discussed in this section, are as follows: Europe, being
one of three major regions involved in the ILC project,
delivers 1/3 of the non-CFS (civil engineering and conventional facilities) components of the ILC accelerator.
The CFS work and components will naturally be constructed in and installed and commissioned by the host
nation. The models follow recommendations given in the
Nomura report [11] and are also drawn from the ILC
Project Implementation Planning (PIP) document [12].
The models discussed correspond to an overall European
contribution of around 1090 Me and 1900 FTE-year to
the ILC accelerator project.
Figure 2 shows the primary cost drivers of the ILC as
identified in the ILC TDR [9]. The dominant cost driver
is the production of approximately 930 SCRF cryomodules. Given European expertise, existing infrastructure,
and proven industrial capability arising from the construction of the E-XFEL and ESS, it is widely assumed
that a large fraction of the European in-kind contribution will be in the form of cryomodules. The ILC TDR
• Technical preparation of the major European deliverables foreseen for the construction phase. This
covers final technical specifications, final prototypes, the preparation of pre-series orders and the
preparation of local facilities. A particularly important point for Europe is the transfer of European
XFEL know-how and the preparation of the relevant facilities for ILC construction.
• The second major technical activity will be the organisation of a strong European design office for
ILC that will liaise with other such offices: there
will certainly be a host-lab office in Japan, but additional international design offices will be required.
In Europe, the installation of a central European
Design Office at CERN with satellite offices in other
European laboratories is considered the most viable
model.
• The third key activity in the preparation phase will
be negotiations about the final European ILC contributions, about the organisation of the project in
3
get involved, based on experience with other accelerator projects than those providing the information in the
table.
As discussed in Section II B, 5% of the total value and
10% of the personnel are assumed to ramp up during
the four-year preparatory phase. The profiles shown in
Fig. 3 also includes a fraction of the expected lab services
personnel, which will almost certainly be required during
the preparatory phase.
assumed that three, possibly four, production sites would
be required worldwide. The European XFEL has been
constructed by a consortium of several European countries, with DESY providing overall coordination. Based
on this experience and the known published cost of the
E-XFEL cryomodules, we have produced a model for
producing and testing one-third of the cryomodule production (310 cryomodules). This model has then been
used to scale to other possible contribution scenarios discussed below. The resulting cost per cryomodule is about
1.65 Me (material and labour), including module production and 100% testing of cavities and cryomodules,
which represents an approximate reduction of 26% over
the actual E-XFEL cost. This reduction has been estimated through the higher production numbers and the
re-use of existing E-XFEL production and testing infrastructure. Where applicable, a mild learning curve slope
of 95% has been applied, assuming two vendors for procurement of all major sub components.
25%
Preparatory Phase
Construction
20%
15%
10%
5%
Primary cost drivers for the ILC
0%
HLRF
7.5%
SCRF
26.9%
Other
22.3%
CFS
34.8%
-3
Main Linac (nonSCRF)
2.0%
RTML
4.2%
Cryogenics
8.5%
Damping
Rings
5.6%
Positron Source
2.6%
-2
-1
0
1
2
3
4
5
6
7
8
5
6
7
8
Year
20%
Preparatory Phase
Construction
15%
BDS
3.0%
Other
4.3%
10%
Electron Source
0.7%
5%
FIG. 2. Primary cost drivers for the 250 GeV ILC as identified in the ILC TDR [9].
0%
-3
-2
-1
0
1
2
3
4
Year
Europe not only has expertise in cryomodule production, but also in many other of the subsystems required
for the ILC. A European contribution to ILC could therefore include other items in addition to cryomodules. As
an example, providing one third of the klystrons, modulators and associated controls (low-level RF) needed for the
SCRF linacs would cost around 155 Me, one third of the
cost of the cryogenics systems would be roughly 143 Me,
and supplying a fraction of the accelerator components
(vacuum, power supplies, magnets, computing and controls etc.) needed for the project could easily reach a cost
of approximately 345 Me. Figure 2 also shows the ILC
TDR costs broken down by both accelerator sub-system
and technical components, not including CFS, installation or SCRF cryomodules.
The experience of the European countries, organised
according to sub-systems, including overall design studies, are shown in Table III. There is significant potential
for the countries to get involved in other activities than
shown in the table, and for other European countries to
FIG. 3. An estimation of the cost and personnel profile cover
the preparatory phase (years -3 to 0) and the construction
phase (years 1 to 8) for the 1/3 model of a 250 GeV machine,
as a fraction of the totals. In this timeline, year 1 corresponds
to the first year of construction, currently foreseen in 2023
Top: material costs. Bottom: explicit personnel in FTEyears.
D.
Organisation of the accelerator activities
In this short section, we discuss possible organisation
forms of a European participation in the ILC. Given the
physics interests in a future e+ e− accelerator, the ILC
project is likely to imply a substantial investment from
the European perspective. This fact highlights the necessity for a high-level agreement about the level of European participation in ILC to be formalised between
2020 and 2023 if the currently assumed time-line of the
4
SCRF
CERN
France
Germany
Italy
Poland
Russia
Spain
Sweden
Switzerland
UK
X,E,G
X,G
X,E,G
X,E
X
X,E
E
HLRF
Sources
C,O
O
G
G
X
Damping
Rings
Instrumentation
Beam
Dynamics
G,C,O
C,G
A,G
X
C,G
G
G
G
G
O
G
G
C,G
C,G
G
X,C
A,C,G
Cryogenics
O
X,O
E,O
X,E,O
A
E
Beam
Delivery
System
C,G
G
C,G,A
C,G,A
TABLE III. European expertise relevant for ILC accelerator construction, based on experience in the recent past. This is
based on two major construction projects, the E-XFEL (X) and the ESS (E), several more R&D oriented efforts namely the
GDE/LCC (G), ATF-2 (A), CLIC (C) and experience in other accelerator projects (O)
ropean programs like the EUDET initiative (2006-2010),
the AIDA program (2011-2015) or the AIDA-2020 program (2015-2020). In Europe, both CERN and DESY
act as a hub of activity and provide common infrastructures and facilities including test beams. Programs in
Asia, in particular in Japan, and in the Americas have
equally played an important role in the ILC concepts.
III.
Be
lg
C E i um
R
DE N
S
Cz Y
ec
Fr h R
an
ep
ub
Ge ce
lic
rm
I s r an
y
ae
Ne l
th
N o e rl a
r
n
Po way ds
l an
Se d
rb
Sp i a
ai
UK n
ILC project is to be respected. On the accelerator side,
the typical organisational model during the construction
phase is based on a leading host laboratory supported by
bi-lateral agreements for in-kind deliverables from other
funding agencies and laboratories. This was the model
used during the LHC construction. The exact organisation of Europe’s contribution to the ILC is not clear
as of today and beyond the scope of this document. As
documented above, there is a very strong potential for
European contributions to the ILC accelerator construction. To organise a broad scientific and technical European ILC effort, involving coherent contributions from
many participating institutes and countries, seems to be
the most realistic and cost-effective scenario if executed
with CERN in a leading coordinating role.
✦✦✦✦✦
✦ ✦✦
Tracking
✦✦ ✦✦ ✦
✦✦
Calorimetry ✦ ✦ ✦ ✦ ✦ ✦ ✦
✦✦✦✦✦
MDI
✦✦
✦
✦
Integration
✦✦ ✦
✦
Vertexing
DETECTORS
Detectors at colliding beam facilities are large international efforts, realised by strong collaborations. Typically
many countries join forces, and contribute mostly in-kind
to the building of the detector systems.
Within the ILC project, the community has come together behind two complementary detector concepts, the
SiD and the ILD concept. After a call for “letters of
intent” in 2009, the proposals submitted by SiD and
ILD [13, 14] were down-selected for validation. The two
detector concept groups then presented their Baseline
Designs in Volume 4 of the ILC TDR [15].
A.
TABLE IV. An overview of recent activities in the area of
ILC-related detector R&D and integration in Europe based
on a 2015 survey [16].
A summary of recent activities in ILC-related detector R&D in Europe is given in Table IV [16]. This table
includes activities for CLIC, but not other more generic
detector R&D that can be applied to the ILC detectors.
The strength in R&D as well as the work on the detector concepts has put Europe in a strong position to
contribute significantly to the future ILC detectors.
The technological developments have been described
in detail in [1]. The detectors at the ILC are very different from those at the LHC in that they can focus much
more strongly on precision measurements. This is possible since the environment at an electron positron collider
is much more benign than at a hadron collider. Radiation hardness hardly plays a role in designing the detec-
ILC detector competence in Europe
Europe has participated strongly in the global work
on the ILC detector concepts and related technological
developments. Initiated by the TESLA project at the
start of the century, an international effort was put in
place to develop the needed detector technologies. This
is augmented by strong national support, but also by Eu5
tween the detectors and the accelerator is however essential.
During the preparation phase, there are four major
milestones for the detectors.
tors. Multiple interactions, which are a major challenge
at the LHC, are essentially not present. There is no trigger necessary and every crossing with collisions present
will be recorded. Due to the long gap between the ILC
bunch trains power pulsing of the electronics is possible leading to significant savings in the overall power
and material budget. These different boundary conditions allow a detector optimisation complementary to the
one at the LHC. A focus on detailed event reconstruction, on high-precision vertexing and high-precision highefficiency tracking and highly detailed imaging calorimetry is possible. As a guiding principle, Particle Flow has
been widely accepted and is used by both SiD and ILD
to characterise the performance of the complete systems.
European groups have played strong roles in nearly all
areas of detector design and development for the ILC.
Particle flow calorimetry as a core element of ILC detectors, has been strongly pushed by European groups,
mostly within the CALICE collaboration. Many developments on high-precision vertexing, in particular in the
area of Monolithic Active Pixel Sensors (MAPS) technology, have come from European groups. The development of high-precision gaseous detectors based on micropattern gaseous detectors has been dominated by European groups. Last but not least, Europe has played a
central role in the Machine-Detector-Interface and integration issues of both detectors.
B.
• Optimisation After the approval of the ILC the
design of the existing detector concepts will need to
be reviewed and refined. We expect that the community supporting these detectors will grow substantially. The design will also profit from the recent experiences of the LHC upgrade program, and
other major detector construction projects.
• Integration into the ILC After the choice of the
final location of the interaction region of the ILC,
the detector designs need to be adapted to the conditions of the site in terms of hall size, transport capabilities and assembly space. Even though significant preparatory work on these questions is already
happening, much more will be required. In particular the experience from Europe and from CERN
will be invaluable.
• Prototyping and Validation The ILC detectors
have already reached an impressive level of maturity - more so probably than at any other largescale HEP project at a similar stage in the past.
Nevertheless the final designs and decisions will
need a very vigorous and high-quality testing and
prototyping program, to demonstrate the technical
readiness, and to provide the basis for final technology decisions. This will require access to test beam
and testing infrastructures in Europe and beyond,
and will put particular demands on the test beam
installations at CERN and at DESY. This process
will continue well beyond the stage of the technical
design report and approval of detectors, into the
construction phase.
ILC Detector preparation phase activities in
Europe
The community is well prepared to move forward
quickly once the ILC turns into a real project. We anticipate that detector construction will follow a path similar to that of the LHC detectors. Once the ILC laboratory has been formed, detector collaboration will formally start and develop concrete proposals based on the
existing work for detectors at the ILC. To govern and
organise this, strong central laboratory support will be
essential. The host country would have to play a special
role in this, but strong regional centres will also be very
important.
In Europe, CERN would be a natural candidate for
such a regional centre, but national laboratories like
DESY or others could also play this role for parts of
the detector. Examples for such more regional centres
within the LHC are the Detector Assembly Facility at
DESY, used for the construction of parts of the upgrades
to the LHC detectors, the CMS centre at Fermilab in the
United States, or the CERN neutrino platform towards
a European role in the long baseline experiments DUNE
and HyperK.
In contrast to the accelerator, within the overall guidelines defined by the host organisation the collaborations
themselves will define and institute the needed structures
to design and build the detectors. Strong support from
the host organisation on all the issues of interfaces be-
• Technical Design Report for the detectors
At the end of the preparatory phase, ILC detector concepts will present detailed technical design
reports to the community and the funding bodies.
Based on these reports the final decisions on which
detectors will be build will be taken.
Besides strong national support, the structuring of the
European contribution should benefit from corresponding funding in upcoming calls by the European Union.
C.
Estimation of a European in-kind contribution
to the ILC detectors
In high-energy physics, the financial contribution to
the detector construction and operation is typically assumed to be proportional to the number of authors of the
detector collaboration. In the LHC experiments, Europe
accounts for about 50% of the members, in non-European
experiments like Belle-II, European groups contribute
6
and AIDA-2020, the Linear Collider Software has now
been expanded for use at test beam experiments and beyond the ILC community.
In contrast to LHC computing, where a lot of the efforts are driven by pure size and data volume, the anticipated data rate from an ILC experiment is smaller by
at least one order of magnitude. The computing architecture needed for ILC will follow the one for the LHC
and while significant resources are needed to serve the
experiments, these demands could already be met today
without problems. The major computing challenge at
the ILC will be the development and provision of advanced reconstruction and analysis tools, which will be
capable of meeting the very challenging precision goals.
In many cases, the requirements for these systems will go
significantly beyond LHC/HL-LHC, and will require significant R&D. Europe is in an excellent position to play
a leading role in this part of the ILC project, based on
its experience in LHC computing, and its contributions
to ongoing linear-collider computing.
about a 1/3 share. Most likely an experiment at the ILC
would be closer to a Belle-II-like model, though, given
the large interest in the community, possibly somewhere
in between Belle-II and the LHC.
Taking the cost numbers from the ILC TDR [15], the
European share for the detector construction is in the
order of 270 Me, which is comparable to the cost for the
ongoing upgrade of the LHC detectors for the HL-LHC.
At the moment, some 57 institutions from 14 European
countries have expressed an interest in participation in
ILC-related detector work, a number that will increase
after the ILC approval.
D.
Organisation of the detector activities
Traditionally, European groups have participated in
projects outside CERN using bilateral agreements between the individual European countries and the host
nation. One example is the European participation in
the B-factories at SLAC and KEK or in the Tevatron
programme at Fermilab.
More recently, the European participation in
the long-baseline neutrino programme at Fermilab
(LBNF/DUNE), while still being negotiated in the
traditional bilateral way, has been augmented by the
European Neutrino Platform hosted by CERN, which
offers technical infrastructure and support for European
groups working on detector and other contributions
to long-baseline neutrino projects. CERN is also now
formally a member of the DUNE collaboration. In any
case, as already outlined in Section II D, our current
assumption is that CERN will play a leading role in the
European participation in the ILC, with strong support
by the national laboratories.
E.
IV.
DISCUSSION
The ILC with a scientific program as outlined in [1],
ranging from an initial stage at 250 GeV centre-of-mass
energy, and reaching to higher energies up to around
1 TeV, will make major contributions to our understanding of the universe. It will be a large-scale international
facility, which will complement and extend the science
done at the LHC. It will pave the way - primarily through
precision studies of the Standard Model - towards answering very profound questions on the nature of our
universe. The ILC will be central to define the route
particle physics should take after the LHC, and thus not
only make major scientific contributions, but will help to
shape the future of the world-wide HEP program. Strategy processes on the national and international level have
repeatedly come to the conclusion that electron-positron
collisions are at this time essential for progress in our
field.
We have described above the degree of preparation and
of community involvement in the development of the accelerator and of the detectors at the ILC. This community is strongly committed - as shown by decades-long
investment in the R&D and prototyping of technologies
- to build the most advanced and best possible accelerator and detector. The community is already very sizeable as can be seen from the list of signatories of the
ILC Technical Design Report which includes 2400 signatories, 48 countries and 392 Institutes/Universities. In
Europe, the community has united behind the series of
European-funded projects like (EUROTeV, CARE, ILCHiGrade, E-JADE, EUDET, AIDA and AIDA-2020) and
SCRF construction projects like the E-XFEL and ESS.
This has resulted in Europe playing a very visible leadership role in the development of the ILC.
Computing
As has been pointed out in the overall document on
ILC [1], computing and data handling have been key
to the successful feasibility study for the ILC. The ILC
community has from the start invested in generic and
widely usable tools. Starting from the initial development of a generic and detector-independent data model,
the LCIO [17] framework, a powerful and at the same
time comparatively simple software infrastructure has
been developed. All parts needed to simulate and to
analyse events from the ILC are available to the community. A key motivation for investing in this software and
computing infrastructure has been to enable realistic and
reliable studies on the science potential of the ILC. The
Linear Collider Software is shared by ILC and CLIC, the
concept groups, and most of the R&D groups working on
linear-collider-related studies.
Europe has been a driving force in this endeavour.
Strongly supported by both DESY and CERN and
thanks to EU support in programs like EUDET, AIDA
7
A.
European participation in the long-baseline neutrino program at Fermilab (LBNF/DUNE).
Political synergy between Japan and Europe
Interest in the ILC in Japan has been steadily growing
for many years. The perspective of hosting the infrastructure in the country is promoted by political (Diet
Federation, Tohoku district) and industrial (AAA consortium) entities and finds strong support in the scientific community (KEK, HEP community, JAHEP). The
project is being examined in detail by bodies charged
by the Japanese government. The scientific interest and
political engagement of partner countries is a major concern for the Japanese authorities. This applies to Europe
in particular because of its expertise, capacities and involvement.
The political plurality of Europe necessitates an initial
approach by the Japanese authorities via bilateral discussions with individual countries, where ILC may appear in a broader landscape embracing other advanced
technology topics of mutual interest. This concept was
first applied in January 2018 when an official Japanese
Delegation visited France and Germany. The Delegation
was composed of members belonging to the Parliament,
to MEXT, to the AAA industry-academy consortium, to
the Tohoku district governance and to the HEP community. Meetings took place at the French and German
Parliaments and Ministries of Research. Some of the Delegation members took the opportunity to visit CERN’s
infrastructures. The plan was next to extend such discussions to other countries as well as European Institutions.
This trip of the Japanese Delegation to France and Germany was complemented by several reciprocal visits of
French and German Parliament members in Japan during 2018, where the interest of both countries in the ILC
was explicitly expressed in the presence of a broad panel
of Japanese political representatives assuming a contribution of Europe to the total construction cost in the
order of 20% of the accelerator. This quantity matches
the 1/3 contribution to the accelerator, excluding the
civil engineering and infrastructure that are considered
host responsibilities, and to the detectors as has been
discussed in previous sections.
B.
C.
Leveraging the expertise and the production
capabilities of European industry
With its strong academic and industrial involvement in
the realisation of the E-XFEL, Europe is particularly well
prepared to contribute to the ILC construction. Based
on its comprehensive expertise and its demonstrated production capability for all main components of such a machine, European industry is poised to play a central role
in the project realisation.
The example of the E-XFEL illustrates how technological innovation driven by particle physics impacts research in other domains, such as biology, pharmaceutics
and material science. Moreover, the technological advances provided by the R&D for the ILC and E-XFEL
are now being used to realise other infrastructures such
as the ESS. The achieved high performances of the EXFEL technology resulted also in its adoption in the USA
(LCLS-II at SLAC) and China (SHINE in Shanghai) for
high-brilliance light sources, to be constructed in part by
European companies which have realised the E-XFEL.
These companies are well aware of the ILC project and
follow its evolution with strong interest. Interactions
with industry take place regularly e.g. at the international linear collider conferences in dedicated industrial
sessions. These regular sources of exchange emphasise
that the attractiveness of the ILC for European industry
is multi-faceted; it is seen as a way to maintain technological leadership in this area.
D.
Conclusion
Europe has demonstrated leadership in both the accelerator and the detector part of the ILC project. Scientifically the case has been shown to be stronger than
ever. European industry is technologically well qualified
and prepared to construct important parts of the ILC
accelerator and detectors. The ILC project is comparable in size to the LHC. The European involvement in a
Japanese-hosted 250 GeV ILC, as discussed in this document, is around 20%. The ILC project fits well with
the HL-LHC time-line moving into major construction
around 2025 and will play a crucial role in encouraging
a new generation of researchers to enter particle physics
while maintaining present expertise. A strong European
linear collider community exists which is eager to participate in the project and to strongly contribute to its
realisation.
Organization of an European contribution
Sections II D and III C give an initial understanding on
how the future European contribution to the ILC project
could be managed for both the accelerator and the detectors. It is proposed that CERN, with strong support
from the national laboratories (DESY, Saclay, etc.) will
play a leading role in the European participation.
In addition, bilateral agreements between Japan and
interested European countries should also exist for specific studies, developments or deliverables. A similar
scheme has already been put successfully in place for the
8
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APPENDIX A: LIST OF SUPPORTING DOCUMENTS
• ILC TDR documents;
• ILC general overview, being specifically produced for the European Strategy Process;
• European ILC Preparation Plan (EIPP), produced under the E-JADE project;
• Linear collider Detectors R&D Liasion Report;
• Green ILC project: reports and web page;
• Letter from the KEKs ILC Planning Office.
Supporting documents web page:
https://ilchome.web.cern.ch/content/ilc-european-strategy-document
APPENDIX B: GLOSSARY
• AAA: The Japanese Advanced Accelerator Association promoting science and technology (http://
aaa-sentan.org/en/association/index.html).
• AIDA: Advanced European Infrastructures for Detectors at Accelerators. AIDA was funded by the EU under
FP7 (https://aida-old.web.cern.ch/aida-old/index.html).
• AIDA-2020: Advanced European Infrastructures for Detectors at Accelerators. The successor of AIDA; AIDA2020 is funded by the EU under Horizon2020 (http://aida2020.web.cern.ch/).
• CALICE Collaboration: R&D group of more than 280 physicists and engineers from around the world,
working together to develop a high granularity calorimeter system optimised for the particle flow measurement
of multi-jet final states at the ILC running, with centre-of-mass energy between 90 GeV and 1 TeV (https:
//twiki.cern.ch/twiki/bin/view/CALICE/WebHome).
• CARE: Coordinated Accelerator Research in Europe. CARE was funded by the EU under the FP6 programme.
• E-JADE: The Europe-Japan Accelerator Development Exchange Programme. E-JADE is a Marie SklodowskaCurie Research and Innovation Staff Exchange (RISE) action, funded by the EU under Horizon2020 (https:
//www.e-jade.eu/).
• EUDET: Detector R&D towards the International Linear Collider. EUDET was funded by the EU under the
FP6 programme (https://www.eudet.org/).
• European XFEL: The European X-Ray Free-Electron Laser Facility (European XFEL) at DESY (Hamburg,
Germany) (https://www.xfel.eu).
• EUROTeV: European Design Study Towards a Global TeV Linear Collider. EUROTeV was funded by the
EU under the FP6 programme (https://www.eurotev.org/).
• ICFA: International Committee for Future Accelerators (http://icfa.fnal.gov/).
• ILC-HiGrade: International Linear Collider and High Gradient Superconducting RF-Cavities. ILC-HiGrade
was funded by the EU under the FP7 programme (https://www.ilc-higrade.eu/).
• JAHEP: Japanese Association of High Energy Physics.
• Japanese National DIET: The National Diet is Japan’s bicameral legislature. It is composed of a lower house
called the House of Representatives, and an upper house, called the House of Councillors.
• LCLS-II: The hard X-ray free-electron laser at SLAC (Stanford, USA)(https://portal.slac.stanford.edu/
sites/lcls-public/lcls-ii/Pages/default.aspx).
• MEXT: Ministry of Education, Culture, Sports, Science and Technology (http://www.mext.go.jp/en/).
• SHINE: Hard X-Ray free electron laser facility in Shanghai.
10