Overview of the ILC,
its significance and impact on theregion

Masakazu Yoshioka
Iwate University, Iwate Prefectural University
Visiting Professor
High Energy Accelerator Research Organization KEK Professor Emeritus

Last week, Professor Atsuto Suzuki asked me to give alecture at this school !

Former KEK DG
President of IPU

Suzuki-sensei is a great physicist.
As far as I know, he has made many achievements inneutrino physics and trained many students.
I am sure you are well aware of his achievements atKamiokande, Super-Kamiokande, and KamLAND.
Among them, my personal favorite achievement is thathe opened the door to Earth neutrino science.
By detecting unti-neutrino from the earth
at KamLAND, it was clarified that thereason why the Earth's interior is still hot
today is that the energy of radiation
emitted from unstable nuclear species isconverted into heat.

He was recently honored as a Person of Cultural Merit and was also appointed as amember of the Japan Academy of Sciences.

On the other hand, I specialize in accelerator science and have been responsible
for the construction of Japan's large accelerators such as
TRISTAN, KEKB, and J-PARC,
and have also been involved in the R&D of linear colliders since early 1980s.
I also developed an accelerator-based cancer treatment system.
Although backgrounds of Suzuki-sensei and myself as researchers are very
different, we share the same age and a love of Japanese sake in Iwate.

For these reasons, my lecture is not a substitute for Suzuki-san's,
and the content will be biased toward accelerators.
From here, I will proceed the lecture in an interactive way.

Q-1: As an energy-frontier accelerator why we need both hadron and leptoncolliders?

LHCILCQ-2: Why ILC is the next generation Lepton Collider after LEP (predecessor ofLHC)?

©ICEPP Tokyo

Why is ILC linear? (LHC is circular)• If it's circular, the electrons emit a lot of synchrotron radiation and lose energy.
• Synchrotron radiation loss is inversely proportional to the fourth power of the particle mass.
• Since proton mass is 2000 times the electron mass, proton synchrotron radiation loss is nota problem• If it's linear, it won't emit synchrotron radiation, so we're going to linearize the lightelectron-positron collider.
• However, there is a tradeoff. With a circular collider, the same particle has multiple
opportunities to collide, but with a linear case, the collision of accelerated particles is a oneshot deal

Original slides by Professor
Emeritus Hitoshi Yamamoto,Tohoku University

Q-3: Why the realization of the ILC will take more time than the LHC? (Notpolitical but technical question)
A-1: Issues are quality control, mass production and cost reduction ofsuperconducting accelerators
Yes, we can ! è See next page (Euro-XFEL)

A-2: Beam control technology, especially collision control by narrowing the beam
size to nanometer size
Yes, we can ! èSee ATF-II@KEKEuro XFEL in Hamburg

X-ray free electron laser (synchrotron radiation) facility in operation
since 2017 in Hamburg, using exactly the same technology as theILC, 10% the scale of the ILC ... in other words, the basic
technology of the ILC has been established.

Colliding particles in a single shot deal
Beams of particles are bunched (swarmed).
Reducing the size of the bunch (narrowing the beam) makes collisions more likely.
Linear colliders especially need to narrow the beam size.

The role of the accelerator is all about accelerating and colliding well.

Original slides by Professor Emeritus Hitoshi Yamamoto, Tohoku University

Let's understand the technology to focus beams to nanometer size and control
collisions. (1) Realizing low beam emittance (radiation damping) and (2)goodchromaticity correction.

Normal light focusing

Minimize the beam emittanceand realize strong focusing
Accelerator beam is
not completely
monochromatic.

Need chromaticity
correction

Laser light focusing

ATF results meet ILC's goalsShintake laser monitor for beam size measurement
Laser light is splited and meet again.
Then laser interference fringe is made, which is a target tomake Compton scattering.

Beam Energy

ATF-IIachieved

ILC design

1.3 GeV

41 nm

75.7 nm

125 GeV

4.2 nm

7.7 nmBeam size is inversely proportional to the square root of energy.
ATF-II results meet ILC goals.

ILC video courtesy of Rey.HORI

Q-4: The core technology of the ILC has been achieved, so why we continue
further development and research?
18 work packages set up byICFA-IDTl Frontier accelerators use the best technology
available at the start of construction, aiming toachieve better performance and lower cost.
l This is very different from industrial or medicalaccelerators.
l We continuously develop and adopt evenhigher technology after construction andoperation begins, and upgrade itsperformance.
l Linear accelerators fit very well with this.

Q-5: Why was the Kitakami Highlands chosen as a candidate site for the ILC?

The terrain is gently rolling hills, suitable for tunneling.

16Granite is a deep-bearing igneous rock. Magma solidified over a long period of time andsurfaced on the ground surface due to its slightly lower specific gravity.

17AccesstunnelDamping AccessRing tunnel
Access tunnel
tunnelAccesstunnelAccesstunnelElectron Main Linac Tunnel

Positron Main Linac Tunnel

Accelerator tunnels are excavated along the geoid
and the final focus tunnel is excavated in a laserstraight.
Excavate five access tunnels first, thenproceed to the main tunnel

Courtesy of Professor Hitoshi Hayano

Bird's eye view of ILC Kitakami candidate site

Positron Linac

Damping RingElectron Linac

Rey.hori/KEK

Colliding point

Tunnel design for ILC Kitakami candidate site (ILC 250GeV 20.5km)
19

Courtesy of Professor Hitoshi Hayano

l Timeline shown by KEK
Director Generall The IDT phase, shown inlight blue, was added to theprevious timelinel We will strive to start
construction as soon as
possible !!!

盛岡ロータリークラブ

20

Last chapter of European
Strategy in 2020

The ILC should also base its policy on this strategy

List of elemental
technologies foraccelerators, detectors,and computing

Create a new
industry in theprivate sector

So far, many newindustries have sprung up
in the region.

l My last topic is about town planning/development
triggered by the ILC.
l We need wide-area planning with Sendai andMorioka as the dipolesl Ecosystem already under construction in Sendai,
triggered by the construction of a synchrotron
radiation facilityl As a community of researchers and engineers, it
should be designed as a community of 200-300 units,each with its own local characteristics.

ILCを契機とした広域エコシステム構築

盛岡ロータリークラブ

NTTファシリティーズ・
平井さん作成27

Summaryl ILC is the most sustainable and economical accelerator as Higgs
Factory, which is based on the superconducting technologies.
l ILC is the most advanced Higgs Factory in terms of technology
development, and I personally believe that we are at the point
where construction can begin as soon as the green light is given.
l ILC is the most energy extendible accelerator in future.
l We hope that the IDT/Pre-Lab process will lead to international
discussions on the structure and cost burden of the ILC, and that
construction will begin as soon as possible.
l The ILC's relationship with society can be learned from theCERNʼs experience.
l We are considering town planning together with the local
community in the Tohoku region, using the ILC as a trigger.
l Establishment of Asia's first large-scale international research
institute is a symbol of “Science for Peace”.

Learn from the History of CERN

French physicist Louis de Broglie put forward the first official proposal for the creation of aEuropean laboratory at the European Cultural Conference, which opened in Lausanne on 9December 1949.
First proposal was only 4 years after the end of WW-II

In the present era of war and infectious diseases, wemust realize the ILC in Japan, the first large-scaleinternational research institute in Asia, and use it as asymbol of Science for peace and world wide brain
exchange.