J-PARC

JAPAN PROTON ACCELERATOR RESEARCH COMPLEX

Facilities at J-PARC
The J–PARC stands for Japan Proton Accelerator Research Complex and it is a new and exciting accelerator research facility
in Japan. J-PARC has three proton accelerators and three research facilities with using MW-class high power proton beams,
which generate neutrons and mesons, to underlie the development of advanced science.

Overview of J-PARC

3 GeV Synchrotron( 25 Hz, 1MW )Linac( 330m )Neutrino to Super-Kamiokande

50 GeV Synchrotron( 0.75 MW )Nuclear Transmutation (Phase 2)

Materials and Life Science Experimental Facility

Hadron Experimental Facility
The area of J-PARC is 65 ha (160 acre). It is 14 times as large as a baseball stadium.

Accelerator layout in J-PARC
Neutrinos toSuper-Kamiokande

Materials and Life Science
Experimental Facility
Linac

50 GeV
Synchrotron(Normal conducting)

3 GeV
Synchrotron

Linac(Superconducting)Nuclear
Transmutation
Hadron ExperimentalFacility

Phase 1
Phase 2

J-PARC is a joint project between two organizations, High Energy Accelerator Research Organization (KEK) and Japan Atomic
Energy Agency (JAEA). The facility is located in Tokai village in the northern region of Ibaraki prefecture, JAPAN.
Construction started in April 2001, and in the spring of 2009 (end of JFY2008) the Phase 1 project was completed after eight
years of construction period.
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Science at J-PARC
The usage of various secondary particle beams (neutrons, muons, kaons, neutrinos, etc.) that are produced inproton-nucleus reactions (nucleus spallation) is the prime
purpose at the J-PARC.

Our universe has a hierarchic structure of matter. For
example, all of materials are consist of atoms. Atoms canalso be divided into atomic nuclei, and nuclei be divided
into nucleons (protons and neutrons), and ﬁnally quarks.
Naturally, many questions come to mind: “How did thedawn of life occur from collections of atoms?”, “What are
the extreme constituents of matter?”, etc.

With these secondary particle beams, three major scientiﬁc goals will be attained:• nuclear particle physics• materials and life sciences• R&D for nuclear transmutation (later, in Phase 2)

J –PARC will throw light on the mysteries of the creationand structure of our universe by investigating matters at alllevels, from quarks to atoms, with using various kinds ofparticle beams.

Secondary beams produced with high-intensity proton beam
Proton is accelerated to the speed close to the light speed
and collided against atomic nuclei of a target metal. Then thenuclei are destroyed, and neutron, meson and neutrino areproduced. J-PARC will use these particle beams for variouskinds of research.

Muon (µ)

Pion (π)π → µ +νNeutrino (ν)

Kaon (K)Proton (p)MW-class proton
accelerator

Neutron (n)Proton Beam

Anti-proton (p̄)

Proton (p)3 GeV, 50 GeV

Need to have high-power proton beams

TARGET
NUCLEUS

Neutron (n)R&D toward Transmutation at 0.6 GeV

Materials & Life Sciences at 3 GeV
Nuclear & Particle Physics at 50 GeV

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Accelerators ofJ-PARC
The J-PARC consists of the following accelerators:• 400-MeV linear accelerator (Linac). It is about 330m in length.
• 3-GeV rapid-cycling synchrotron (RCS), which provides proton beams at 333μA (1MW). It is about 350m in circumference,and can accelerate protons up to about 97% of light speed.
• 50-GeV synchrotron, which provides proton beams at 15μA (0.75 MW) . It is about 1600m in circumference, and can accelerate protons up to about 99.98% of light speed.
(Phase 2, we have a plan for construction of superconducting Linac, to increase the energy from 400 to 600-MeV)

LINAC (Linear accelerator: 330m in length)

50GeV synchrotron (It is 1600m in circumference)

RF Cavity?

Many new technologies have been invented and developed for the J-PARC accelerator. As accelerators are a precision
machine, they are installed within a tolerance of 0.1 mm. All ofJ-PARC accelerators are placed in the tunnel established underground. The tunnel is made with thick steel-framed reinforced
concrete.
The proton speed is very important for nucleus spallation,
thereby producing neutrons and mesons to be used in study.
The RF (radio frequency) accelerating system is used for theacceleration. Finally, the proton beam is accelerated nearly tothe light speed.

324MHz Klystron (RF Power ampli�er)

Why J-PARC’s synchrotron is not a precise circle, but a triangle withhaving rounded corners?

Why?

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3GeV synchrotron (It is 350m in circumference)

Synchrotron accelerator is a round type accelerator. Many large electromagnets are set to bend
and squeeze the proton beam. Note that J-PARC’s synchrotron is a triangle with having rounded
corners. The reason why we have this shape is that it is necessary to get the proton beam in andout from the accelerators through a linear part. There is one inlet and two outlets for 50GeV
synchrotron for the proton beam, thus, these three linear lines make a triangle.

Nuclear and Particle Physics
FacilityAt the 50GeV Synchrotron, nuclear andparticle physics experiments are performed
using high-intensity beams such as thekaon beam, pion beam, neutrino beam aswell as the primary proton beam.
In these research ﬁelds one looks foranswers to the very fundamental questions
such as; “What are the extreme constituentsof matter?”, “What are the fundamental
interactions or forces acting between particles?” and “What is the origin of mass ofelementary particles?” In order to study
these questions, the experiments with highprecision, with very new phenomena orwith exotic states will be pursued using thesouth sidehigh-intensity beams.
The Hadron (Hadron; an aggregate of quarks) Experimental Hall
uses the slow extracted proton beam from the 50GeV Synchrotron.
There are several secondary beam lines, where secondary particles,
such as pions (pi mesons) and kaons (K mesons), produced at the
production target are transported for experiments.
Studies on “hyper-nuclei”, nuclei with “strange” particles inside, arebeing conducted at the K1.8 beam line using kaons, whose goal is tounderstand the fundamental interactions between hadrons.
Rare kaon decays are studied at the KL beam line to investigate
the so-called “CP violation”, a key to understand our universe wherematter dominates over anti-matter. An experiment is planned withthe proton beam to investigate the origin of the hadron mass.

Hadron Experimental Hall

north sidebare quarks
protonWhy is a proton, which consists of 3 quarks, 100times heavier than the sum of 3 bare quarks?

T2K experimentTokai to Kamioka (T2K) is a Japanese-led multinational physics
experiment. High-intensity neutrino beams are directed fromthe J-PARC at Tokai village towards Super-Kamiokande—theworld’s largest underground neutrino detector—located in Hida
city, Gifu Prefecture. As the neutrinos traverse the JapaneseArchipelago at virtually the speed of light, a change occurs in an
essential characteristic—the generation or flavor—of theneutrinos. This phenomenon is known as neutrino oscillation. By
investigating neutrino oscillation, we can uncover the mysterious
characteristics of neutrinos. In particular, we can determine theirrelative lightness, as compared to other elementary particles
such as electrons or quarks, and also the extent of mixing of
neutrino ﬂavors. These are fundamental issues in the ﬁeld of
elementary particle physics, which may provide the key tounderstand the evolution of our matter-dominated universe.

First observation of J-PARC
neutrino on April 22th, 2010

Superconducting Magnets
Near Detector of Neutrino (Magnet Yokefrom CERN)

Decay Volume

J-PARC
Tokai

Super-KAMIOKANDE
Kamioka

Neutrino Beam

295km
Neutrino traveling long-distance from J-PARC to Super-Kamiokande
4Materials and Life Science
Experimental Facility

Mercury Target for Neutrino Production

Extensive scientiﬁc programs covering condensed-matter physics, materials
sciences, industrial applications, structural biology and nuclear/particle physics, will
be carried out at the Materials and Life Science Experimental Facility (MLF).
The MLF provides the world’s highest ﬂux of neutrons and muons by protonimpact nucleus spallation reactions with a 3GeV proton synchrotron of 1MW beampower. The proton beam cascades the graphite target for muons and reaches tothe mercury target for neutrons. 23 neutron beam lines and 4 muon beam lines areplanned and will be installed in the MLF building. Synergetic use of neutrons andmuons at the world’s highest ﬂux will be enabled at MLF, where will be a center ofmaterials and life science researches.

MLF #1 Experimental Hall

MLF #2 Experimental Hall

Neutron Beam Line #19 “TAKUMI”
Neutron Radiography of lily

Since the neutron has a mass that is similar to thatof the hydrogen atom, a magnetic moment but noelectric charge, and a high penetrating power, theneutron can sensitively probe spin correlations, and thelocation and motions of atoms, especially hydrogenatoms, in materials. These characteristics of the neutron
make neutrons play crucial roles in many subjects likestudies of the locations and motions of hydrogen atoms
in biological cells, which is of particular interest in life
science.
Muon target

Hard disk

Hen Egg-White Lysozyme Structure(Water molecules observed with neutrons)

The positive muon (μ+) behaves as a light radioisotope of the proton
in matter. Because of its large magnetic moment (up to three times thatof proton), implanted positive muons have a wide variety of applications
to materials science and biology in a fashion similar to nuclear magnetic
resonance (μSR). Even more importantly, the μSR technique provides
truly complementary information to that obtained from neutron diﬀraction on the same object.
Muon beam line5Transmutation Experimental
Research (Phase 2)
Nuclear transmutation is a physical phenomenon wherea target nuclide transmutes to another one by a nuclear reaction. In the present fuel cycle system for commercial nuclear
power plants, the reprocessing of the spent fuels produces
High-Level Nuclear Wastes (HLWs) including long-lived
nuclides.
If the long-lived nuclides can be converted to short-lived
or stable ones by the transmutation technique, the management period for geological disposal of HLWs could be much
shorter than expected, and this leads to a reduction of theburden of geological disposal.
At phase 2, J-PARC plans to construct the Transmutation
Experimental Facility (TEF) for the basic study of radioactive
waste management. J-PARC will contribute to basic researchand development of transmutation technique.

Partitioning

Nuclear Transmutation
TargetProtonProton Accelerator

Atomic Power Station
Short-lived
Nuclei

NeutronLong-lived
Nuclei

Short-lived Nuclei

High-Level
Waste

Without transmutation...

With Transmutation...
Radiation Level (about 1/200)
Takes 102 yrs to reachthe negligible level

Takes ~104 yrs to reachthe negligible level

Nuclear Transmutation experiment

J-PARC as a World Center

ISIS
GSI

FNAL

CERN

J-PARCISIS : Neutron source at Rutherford Appleton Inst.
SNS : Spallation Neutron Source at Oak Ridge Nat. Lab.
CERN : Research facility in Switzerland
FNAL : Fermi Nat. Lab.
GSI : Heavy ion Inst. in Germany

SNSCenter in neutrino

Center in neutrons

Hadron (Kaons)Hadron (antiprotons)

J-PARC is used by researchers and scientists from all over
the world. Many domestic and overseas researchers gather anduse it for their study. J-PARC will be a world center of science
research.
For the purpose of their easy access and convenience, Users
Oﬃce and laboratory oﬃces are provided in Ibaraki Quantum
Beam Research Center, which is near J-PARC.

We believe that J-PARC will contribute to obtain the most-advanced science and technology,
which resulting to the development and prosperity of humankind in the future.

6KEK / JAEA J-PARC Center
2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan

High Energy Accelerator Research Organization (KEK)
1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan

Japan Atomic Energy Agency (JAEA)
4-49 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1184, Japan