JHF Physics
J. Imazato
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Oho 7-7, Tskuba-shi, Ibaraki-ken, 305-0801 Japan
Abstract. The construction of a high-intensity proton accelerator complex has started in Japan. It will provide a
variety of beams such as neutrons, muons, kaons, and neutrinos etc. Diverse physics and applied physics topics
will be addressed here, with the first beams scheduled for the year 2007. In this talk, the most important physics
objectives and a few typical examples of experiments will be presented.
INTRODUCTION
PARTICLE PHYSICS
A high-intensity proton accelerator complex is now being built in Japan to extend the horizons of hadron beam
sciences in the 21st century [1]. The accelerator complex (so far called JHF x ) consists of a 600-MeV linac, a
3-GeV rapid cycling synchrotron (RCS), a 50-GeV synchrotron (PS), and several experimental facilities. It is a
joint project of Japan Atomic Energy Research Institute
(JAERI) and High Energy Accelerator Research Organization (KEK). The construction has started last year and
it is expected to be completed by the end of Japanese fiscal year 2006 and to provide first beam in 2007. The configuration of the accelerator complex is shown in Fig.l.
The facility is being built in the Tokai site of JAERI on
the Pacific Ocean coast in the neighborhood of already
existing research reactors. The present activities of the
12-GeV PS and the neutron spallation source at KEK
will move there.
The JHF is designed to be an intensity frontier facility
and a variety of secondary beams will be produced there.
The RCS with 1 MW of power will be used for a spallation neutron source and muon beams for materials and
life sciences, by means of neutron diffraction/scattering
and [iSR techniques, respectively. The 50-GeV PS beams
with a 15 jUA current, corresponding to 0.76 MW of
power, will lend high fluxes to secondary meson beams
such as kaons and pions for particle and nuclear physics.
A Neutrino beam will be also one of the most important
beams. The present world's proton machines have typically 0.1 MW level of power both for low-energy and
high-energy machines (see Fig.3) with one exception of
the PSI cyclotron. Our RCS and 50-GeV PS will attain
ten times higher level of 1MW together with the SNS machine under construction. Details of the accelerator are
presented elsewhere in this workshop [3].
Experimental facility
1
An offi cial name of the accelerator facility will be given soon.
The physics potential of high-intensity machines has
been discussed previously [2]. There will be two extracted beams from the 50-GeV PS: one is the slow extraction beam to be used for counter experiments and the
other is the fast extraction beam used for neutrino beam
production. Fig.2 shows the present design of an experimental hall for the slow beam with 3 primary beam lines
and 3 or 4 target stations from which secondary lines are
extracted. The expected beam intensity for a few typical
secondary lines are compared in Fig.3 with the present
machines. We will reap the benefits of beams of about
100 times more intense than at KEK 12-GeV PS and
about 3-4 times as those of BNL-AGS.
Kaon decays
We may characterize the particle physics at JHF as
the high-precision frontier physics using high-intensity
beams. One of the major fields of interest is the rare kaon
decay. Here, one tests the standard model (SM) and look
for new physics as a deviation from it. One may stress
the stand point of symmetry-violation physics of CP, T
and CPT. This physics is a nice complement to B meson
decay experiments and also to collider energy-frontier
experiments.
A topic of current interest is the determination of
CKM matrix and confirmation of the unitary triangle, or
the determination of the p and 7] Wolfenstein parameters.
The most useful decays are the flavor changing modes of
KL -> 7T°vv and K+ -> TT+VV (Fig.4). The former is a
direct CP-violating process dominated by short distance
contributions. The decay amplitude in SM is proportional
to Im(V^) or to the parameter T], namely to the height of
the triangle. The current estimate of the branching ratio is 3 x 10~n. A pilot experiment (E391a at KEK-PS),
aiming at a sensitivity of 10~9~~10, is currently in prepa-
CP642, High Intensity and High Brightness Hadron Beams: 20th ICFA Advanced Beam Dynamics Workshop on
High Intensity and High Brightness Hadron Beams, edited by W. Chou, Y. Mori, D. Neuffer, and J.-F. Ostiguy
© 2002 American Institute of Physics 0-7354-0097-0/02/$ 19.00
6
50GeV
GeVPS
PS
50
Experimental
Area
Experimental Area
GeV PS
PS
33 GeV
(333 µA, 25Hz)
25Hz)
(333MA,
R&D
for Nuclear
Nuclear
R&D for
Transmutation
Transmutation
J
GeV PS
PS
33 GeV
ExperimentalArea
Area
Exoerimental
400-600
400-600 MeV Linac
(Superconducting)
(Superconducting)
_______\
400
400 MeV
MeV Linac
Linac
(Normal
(Normal Conducting)
Conducting)
50GeV
GeVPS
PS
50
µA)
(15MA)
(15
Neutrinosto
to
Neutrinos
SuperKamiokande
SuperKamiokande
guration of
FIGURE 1. Confi
Configuration
of the
theJHF
JHFaccelerator
acceleratorcomplex
complex
ration. BNL-AGS
BNL-AGS is
is also
also preparing an experiment (KOration.
(KO12
−12
PIO)aiming
aiming at
at 10
10~
sensitivity. The E391a setup,
PIO)
sensitivity.
setup, when
when
moved to
to the
the 50-GeV
50-GeV PS, will achieve a sensitivity
moved
sensitivity of
of
14
−14
10~
in aa runtime
runtime of
of 33 ×
x 10
1077 sec accumulating
accumulating 1000
10
in
1000
events. The
The ηT]parameter
parameter can be determined to
events.
to a preciprecision
better
than
10%,
a
result
inaccessible
at
current-day
sion better than 10%, a
current-day
facilities.
facilities.
The KK++ →
—> πTT++νVV
decay is
is complementary
complementary to
The
ν¯ decay
to
K
decay
and
has
a
SM
amplitude
proportional
to
L
K
decay
and
has
a
SM
amplitude
proportional
to
L
p
2 2 ^ 7 ]22 which is rather sensitive to p, the hor~ρPo)
(ρ −
0 ) + η which is rather sensitive to ρ , the horizontal coordinate
coordinate of
of the
the triangle
triangle peak.
peak. The
izontal
The present
present SM
SM
10
−10..
prediction
of
the
branching
ratio
is
(0.75±0.29)
x 10~
prediction of the branching ratio is (0.75±0.29)×10
This decay
decay mode
mode has
has long
long history
history of
This
of measurements
measurements of
of
increasing
sensitivities,
and
two
events
increasing sensitivities, and two events have
have recently
recently
been found
found in
in the
the E787
E787 experiment
experiment at
at BNL-AGS.
been
BNL-AGS. From
From
the
SM
estimate,
one
expects
to
obsereve
100 events
events at
the SM estimate, one expects to obsereve 100
at
JHF. One
One of
of the
the interests
interests in
in investigating
investigating the
JHF.
the unitary
unitary tritrianglelies
lies in
in observing
observing differences
differences between
between kaon
angle
kaon decays
decays
and
B
meson
decays,
where
the
contribution
and B meson decays, where the contribution from
from new
new
physicsmight
might appear
appear as
as aa several
several percent
percent effect.
physics
effect.
Timereversal
reversal invariance
invariance violation
violation (T
(T violation)
Time
violation) is
is also
also
important
physics
complementary
to
CP
violation.
important physics complementary to CP violation. One
One
may test CP violation models assuming the CPT inmay test CP violation models assuming the CPT invariance. T violation can be searched for in the K++ —>
variance.
T violation can be searched for in the K →
7T°jU+ v decay by looking at muon transverse polarization
π 0 µ + ν decay by looking at muon transverse polarization
(P ) which is the normal component of polarization to
(PTT) which is the normal component of polarization to
the decay plane. Because it is a T-odd correlation and the
the decay plane. Because it is a T-odd correlation
and the
final state interaction is very small (10~6), non-vanishing
final state interaction is very small (10−6), non-vanishing
P is a signature of T violation. The interesting feature
PTT is a signature of T violation. The interesting feature
here is the non-existence of a SM contribution. Thus, PT
here
is the non-existence
of aphysics,
SM contribution.
Thus,
PT
is sensitive
to some of new
such as the
multiisHiggs
sensitive
to
some
of
new
physics,
such
as
the
multimodels, leptoquark models and a class of superHiggs
models,
leptoquark
models
a class
of supersymmetric
models.
Now the
KEKand
E246
experiment
is
3
symmetric
models.
Now
the
KEK
E246
experiment
is
improving its limit at the PT ~ 10~
order.
More
than
−3 order. More than
improving
its
limit
at
the
P
∼
10
T
order of magnitude improvement (to the level less than
4
order
improvement
PT ~ of
10~magnitude
) can be expected
at JHF.(to the level less than
PT ∼ 10−4) can be expected at JHF.
Neutrino
Neutrinooscillation
oscillation
Neutrino
Neutrino oscillation
oscillation physics
physics isis becoming
becomingmore
moreand
and
more
more important
important after
after the
the evidence
evidencefor
foroscillation
oscillationwas
was
found
found in
in atmospheric
atmospheric neutrino
neutrino observation
observationbybySuperSuperKamiokande
(SK)
as
well
as
in
solar
Kamiokande (SK) as well as in solarneutrinos
neutrinosatatSNO.
SNO.
The
The K2K
K2Kexperiment,
experiment,running
runningatatKEK
KEK12-GeV
12-GeVPS,
PS,also
also
confirms
confirmsthe
theoscillations.
oscillations.At
AtJHF,
JHF,one
onecan
cantake
takeadvantage
advantage
of
of the
the high
high fluxes
fluxesof
of VνMµ beams
beams(100
( 100times
timesmore
moreintense
intense
than
at
K2K)
to
vastly
improve
these
measurements.
than at K2K) to vastly improve these measurements.The
The
distance
distance to
to SK
SKisis295
295km
kmand
andjust
justthe
thebest
bestcondition
conditionfor
for
the
the relevant
relevantmass
massdifference
differenceregion
regionand
andneutrino
neutrinoenergy
energy
region.
interest
region.The
Thecurrent
current
interestisisthe
thedetermination
determinationofofmass
mass
2
difference,
neutrino
disappeardifference,Am
∆m2, ,relevant
relevanttotothe
themuon
muon
neutrino
disappear2
ance
ofofthe
mixtheMNS
MNS
mixance and
and the
the mixing
mixing angle
anglesin
sin220
2θ2323
2
2
220^ (or sin 20
2 13)
ing
matrix,
and
determination
of
sin
ing matrix, and determination of sin 2θµ e (or sin 2θ13 )
from
The
from an
an electron
electronneutrino
neutrinoappearance
appearancemeasurement.
measurement.
The
3
2
present
constraint
from
SK
isis1.6
x×10~
x×
−3<<Am
2<<3.9
present
constraint
from
SK
1.6
10
∆m
3.9
3
2
2
10~
−3 eV 2, and sin 22023 > 0.97 (90% C.L.). The recent
10 eV , and sin 2θ23 > 0.97 (90% C.L.). The recent
result
K2K isis also
a similar region
result from
from
also showing
showing
regionofof
3 K2K
2
3
2 a similar
2
1.5
x
10<
Am
<
3.9
x
10~
eV
at
sin
226 = 1 (90%
−3
2
−3
2
1.5 × 10 < ∆m < 3.9 × 10 eV at sin 2θ = 1 (90%
C.L.) with an expectation of corresponding improvement
C.L.) with an expectation of corresponding improvement
after the planned 102020 protons on target. The sensitivafter the planned 10 protons on target. The sensitivity at JHF will be <5(sin222023) ~ 0.01 and <5(Aw22) <
ity at JHF
will be δ (sin 2θ23 ) ∼ 0.01 and δ (∆m ) ≤
4
1 x 10~
eV2 after a 5 year run.
1 × 10−4 eV2 after a 5 year run.
As for the electron neutrino appearance experiment,
As for the electron neutrino appearance experiment,
one may push the limit of sin2220^ down to 0.3% level
one may push the limit of sin 2θµ e down to 0.3% level
in 5 years improving the present limit from a reactor
in 5 years improving the present limit from a reactor
experiment
by a factor 20 for the relevant mass difference
experiment by a factor 20 for the relevant mass difference
region.
region.
A neutrino beamline is now being designed based on
neutrino
beamline
is now
designed
theAoff-axis
beam
scheme
with being
a neutrino
beambased
in theon
the
off-axis
beam
scheme
with
a
neutrino
beam
the
direction at a finite angle from the pion beam axis. in
One
direction
at
a
finite
angle
from
the
pion
beam
axis.
One
can obtain a narrow energy spectrum with relatively high
can obtain
a narrow
relatively
peak
intensity.
In theenergy
presentspectrum
case thewith
off-axis
anglehigh
of
peak
intensity.
In
the
present
case
the
off-axis
angle of
2 degrees looks most promising. After a power upgrade,
2 degrees
looks
mostwill
promising.
After the
a power
CP
violation
studies
be also within
scope.upgrade,
CP violation studies will be also within the scope.
Experimental hall (Phase 2)
FIGURE 2. Experimental hall for slow extracted beams at the 50-GeV PS
FIGURE 2. Experimental hall for slow extracted beams at the 50-GeV PS
Muondecays
decays
Muon
Lepton flavor physics will be studied using highLepton flavor physics will be studied using highintensity muon beams. Lepton number violating rare deintensity muon beams. Lepton number violating rare decays such as jU —> ey, /JL —> 3e, /JL — e conversion and
cays such as µ → eγ , µ → 3e, µ − e conversion and
Mu — ¯
Mu conversion have been studied since long imMu − Mu conversion have been studied since long improving their limits. These decays can be pursued at the
proving
limits.
decays can be
pursued One
at theof
50 GeVtheir
PS to
resultThese
in unprecedented
precision.
50theGeV
PS
to
result
in
unprecedented
precision.
One
most interesting decays is the jU — e conversion of
in
the
most
interesting
decaysatom
is the
µ − estate
conversion
in
which a jU~
in the muonic
ground
is absorbed
−
which
in theemitting
muonican
atom
groundThis
stateprocess
is absorbed
by thea µ
nucleus
electron.
has a
byvery
the high
nucleus
emitting
an
electron.
This
process
has a
sensitivity to SUSY-GUT, one of the recent
very
high beyond
sensitivity
to SUSY-GUT,
one of
the recentat
theories
the SM.
Now the MECO
experiment
theories
beyond
the
SM.
Now
the
MECO
experiment
BNL-AGS is being prepared aiming for a sensitivity at
of
16
BNL-AGS
isexperiment
being prepared
aiming
for a this
sensitivity
of
10~
.
An
at
JHF
may
exceed
limit.
10−16
An experiment
JHFa high
may exceed
thisthe
limit.
In. order
to achieve at
such
sensitivity,
PRISM
In
order
to
achieve
such
a
high
sensitivity,
the
PRISM
collaboration is considering to make a high-intensity
collaboration
to rotation
make a technique
high-intensity
muon source is
by considering
means of phase
using
muon
source
by
means
of
phase
rotation
technique
usingin
a fixed field alternating gradient (FFAG) synchrotron
a conjunction
fixed field alternating
synchrotron
in
with a piongradient
capture (FFAG)
and decay
sections with
conjunction
with amagnets.
pion capture and decay sections with
superconducting
superconducting magnets.
NUCLEAR PHYSICS
NUCLEAR PHYSICS
One of the main features of nuclear physics at JHF is
One
of nuclear
JHF is
the of
usethe
of main
strongfeatures
kaon beams
whichphysics
enableatso-called
the
use of strong
kaon
beams
which enable
so-called
strangeness
nuclear
physics
by introducing
s quarks
into
strangeness
physics
by introducing
quarks
into
nuclei. Thenuclear
conventional
S=-l
systems of As and
Z hypernuclei.
systems
Λ and Σ hypernucleiThe
haveconventional
been studiedS=-1
at the
presentofaccelerator
labonuclei
haveKEK
beenand
studied
the they
present
ratories,
BNL,atand
willaccelerator
be pursuedlabofurratories, KEK and BNL, and they will be pursued fur-
ther. Hyperon states deep inside the nuclear medium can
ther. Hyperon states deep inside the nuclear medium can
be studied as well as the hyperon nucleon interactions.
be studied as well as the hyperon nucleon interactions.
By means of y spectroscopy one may also open up a new
By means of γ spectroscopy one may also open up a new
field of high-resolution hypernuclear spectroscopy.
field of high-resolution hypernuclear spectroscopy.
The high flux of kaon beams enables us to explore the
The high flux of kaon beams enables us to explore the
S=-2 system in terms of the (K~− ,K++) reaction leading
S=-2 system in terms of the (K , K ) reaction leading
to E nuclei and double A hypernuclei. The knowledge
to
nuclei
andisdouble
Λ hypernuclei.
The four
knowledge
of ΞS=-2
nuclei
up to now
very poor. Only
events
of
S=-2
nuclei
is
up
to
now
very
poor.
Only
four
events
were found for double A nuclei and the E nucleus
is
were
found
for
double
Λ
nuclei
and
the
Ξ
nucleus
is
yet to be found. As for the H dibaryon only a lower
yet
to
be
found.
As
for
the
H
dibaryon
only
a
lower
bound of mass has been given. There is also a theoretical
bound
of mass
hasthebeen
given. of
There
is also
a theoretical
prediction
about
existence
a mixed
states
of S, 2A
prediction
about
the
existence
of
a
mixed
states
of Ξ, 2Λ
and//.
andInH.order to perform the spectroscopy of the S=-2 sysIn with
order(K~,K+)
to perform
the spectroscopy
ofcross
the S=-2
system
reactions
of very small
sections,
− , K + ) reactions of very small cross sections,
tem
with
(K
we need a K~
beam of high quality and a spectrometer of
we
need
a K − beamThe
of high
and a spectrometer
of
high
performance.
SKSquality
superconducting
spectromhigh
performance.
The
SKS
superconducting
spectrometer currently in use at KEK will be employed at JHF. A
eter
currently
use
at KEK
will be of
employed
at JHF.
A
beamline
withinthe
beam
momentum
1.8 GeV/c
is now
beamline
with the beam momentum of 1.8 GeV/c is now
being designed.
being
Thedesigned.
hyperon-nucleon interaction can be also studied
hyperon-nucleon
also
studied
inThe
scattering.
The cross interaction
section datacan
arebe
still
very
poor
in
section data
are scattering.
still very poor
in scattering.
comparisonThe
withcross
the nucleonnucleon
The
in
comparison
with
nucleon- nucleon
The
interests
will be
thethe
understanding
of the scattering.
baryon-baryon
interests
willinbe
the understanding
of the
baryon-baryon
interaction
terms
of SI/(3) scheme
together
with NN
interaction
SU(3) to
scheme
together
NN
interaction.inItterms
is alsoofdesired
determine
the with
sign (atinteraction.
It
is
also
desired
to
determine
the
sign
(attractive or repulsive) and magnitude of the potential core
tractive
or
repulsive)
and
magnitude
of
the
potential
core
and the strength of spin dependent forces.
andThere
the strength
spin dependent
forces. fields in addiare of of
course
many interesting
There
of coursephysics.
many interesting
fields in inaddition
to theare
strangeness
Hadrons embedded
nution to the strangeness physics. Hadrons embedded in nu-
Proposed
Proposed
•
108
ESS
PSI
SNS This Project
3 GeV
(CW)
100
Materials-Life
Sciences
ISIS
TRIUMF
Nuclear-Particle
Physics
IPNS
This Project
50 GeV
10
AGS
KEK-500MeV
Booster
CERN-PS
1
K-1.8
FNAL-MI
1 MW
SPS
KEK12GeV PS
0.1
K+0.8
K-1.1
107
Power
Particles per second
10000 - =
10000
1000
Comparisonofof Beam
Beam Intensity
Intensity
Comparison
Under
U
Existing
A cconstruction
0^uction Oil Existing
0.1 MW
K+0.8
K-1.8
10
K-0.8
6
K+0.8
105
K-1.8
K-0.8
U70
Tevatron
104
0.01
0.01
0.1
10
10
1
100
100
1000
1000
10000
10000
KEK12-GeVPS
KEK 12-GeV PS BNL
BNLAGS(23
AGS(23GeV)
GeV)
50-GeVPS
50-GeV PS
Energy
(GeV)
Energy (GeV)
FIGURE
FIGURE 3.
3. Beam
Beam power
power of
of world's
world’s proton
proton machines
machines and
and expected
expected kaon
kaon beam
beam intensities
intensities at
at JHF
JHF
clear matter may provide
provide aa hint
hint to
to understand
understand the
the origin
origin
of
of hadron mass, which
which can
can be
be argued
argued in
in QCD theories.
theories.
There are calculations
calculations of
of the
the vector
vector meson
meson mass
mass in
in nunuclear matter and experimental
experimental studies
studies have
have been
been started.
started.
The
The spectroscopy
spectroscopy of
of hadron
hadron itself
itself will
will be
be one
one of
of the
the mamajor
jor fields,
fields, too.
too. Current
Current interest
interest is
is in
in topics
topics such
such as
as search
search
(or identification)
identification) for
for exotic
exotic states
states with
with gluonic
gluonic degrees
degrees
of
of freedom
freedom such as glueballs
glueballs and
and hybrids.
hybrids.
MATERIALS AND
AND LIFE
LIFE SCIENCES
SCIENCES
Pulsed high flux
flux neutron
neutron beams
beams
Neutron diffraction
diffraction has
has a wide
wide range
range of
of applicaapplications in many
many sciences.
sciences. In
In the
the planned
planned experimental
experimental
hall, there will be nearly
nearly 25
25 beamlines
beamlines equipped
equipped with
with
unique diffractometers
diffractometers and
and spectrometers
spectrometers of
of high
high perforperformance, and materials
materials and
and life
life sciences
sciences will
will be
beperformed.
performed.
The 25 Hz pulsed
beam
enables
high-precision
pulsed beam enables high-precision time-oftime-of-
η
_
Κ L−> π 0 ν ν
(ρ, η)
(M)
(0,0)
(0,0)
Κ+
−>
π+ _
ν
ν
(1,0)
(1,0)
Po
ρ0
ρ
FIGURE
FIGURE 4.
4. Kaon
Kaon rare
rare decays
decays and
and the
the unitary
unitary triangle
triangle
flight
flight measurements
measurements to
to determine
determinethe
the scattering
scatteringfunction
function
S(Q,
S(Q,CD)
ω ) over
over aa wide
wide range
range of
of Q
Q and
and co
ω in
in aa high
high resoluresolution
tion setting.
setting.Although
Althoughthe
the average
averageflux
fluxisis smaller
smallerthan
thanthe
the
most
most powerful
powerful reactor
reactor beam
beamby
by aa factor
factorof
offour,
four,the
thepeak
peak
intensity
intensity will
will be
be 200
200 times
times higher.
higher.
High
High flux
flux beam
beam will
will enable
enable the
the studies
studies of:
of:
•• materials
materials with
with large
large unit
unit structure
structure such
such as
as biobiomolecules
molecules and
and soft
soft matters
matters (with
(with smaller
smaller samples),
samples),
•• weak
weak signals
signals from
from new
new type
type of
of weak
weak or
or exotic
exotic exciexcitations
tations in
in condensed
condensedmatter,
matter, and
and
•• dynamical
dynamical properties
properties in
in materials
materials by
by means
means of
of the
the
time
dependent
measurements.
time dependent measurements.
The
Thepolarized
polarizedneutron
neutronbeam
beamwill
willbe
beproportionally
proportionallystrong
strong
enough
enough for
for many
many applications.
applications. The
The industrial
industrial applicaapplications
tions of
of radiography
radiography will
will become
become more
more and
and more
more imporimportant,
too.
tant, too.
Sciences
Sciences with
with neutrons
neutrons
In
In this
this respect
respect one
one of
of the
the most
most important
important fields
fields in
in
which
prominent
development
is
expected
is
structural
which prominent development is expected is structural
biology.
biology. In
In conjunction
conjunction with
with the
the nature
nature of
of neutron
neutron scatscattering
tering that
that the
the sensitivity
sensitivity isis rather
rather uniform
uniform over
over atomic
atomic
number
number ZZ in
in contrast
contrast to
to XX ray
ray which
which has
has the
the sensitivsensitivity
ity only
only to
to heavy
heavy elements,
elements, the
the positions
positions of
of hydrogen
hydrogen
and
and hydration
hydration in
in proteins,
proteins, DNA
DNA and
andphysiologically
physiologicallyimimportant
portant materials
materials will
will be
be routinely
routinely determined.
determined. PhysioPhysiological
logical functions
functions will
will be
be studied
studied in
in inelastic
inelastic scattering
scattering
through
through excitations.
excitations.
A
A new
new field
field will
will be
be opened
opened in
in the
the soft-matter
soft-matter science
science
such
as
polymer
and
liquid
crystal.
These
such as polymer and liquid crystal. Thesematerials
materialsform
form
CONSTRUCTION STATUS
very beautiful higher-order complex structure in a large
spatial scale. To realize the maximum potential of this
probe, it is essential that we cover a wide Q-co range
with high flux neutron beams. The density fluctuation
is known to play an important role in the structural
formation, which might be investigated in time evolution
of S(Q, co). The response of soft matter to external fields
is also an important subject.
The recent observation of quantum effects in the spin
excitation in CuGeO3 suggests another major field at our
facility. In the scattering function, weak strength of magnetic scattering from electrons in the one-dimensional
system was observed outside the classical excitation region. Such a weak signal provides means to study spin
dynamics in magnetic substances. Similar studies of lattice dynamics, electron dynamics and orbital dynamics
will be possible. One of the interests there will be the
understanding of high Tc superconductivity.
High sensitivity for light elements opens up several applications of dynamic process measurements. Recently,
an observation of the drifting of Li ions during the charging and discharging of a lithium battery has been reported. The high neutron fluxes at JHF will open up many
applications of this kind.
Industrial applications of neutrons is another facet of
JHF. The high flux beams make the radiography of the
interiors of bulk materials feasible. One can exploit this
technique to characterize new materials from the images created under various conditions of multi-parameter
space such as concentration, temperature, pressure etc.
The scattering measurements under extreme conditions
of pressure and temperature will become possible, too.
The use of polarized neutrons is beneficial not only for
the study of magnetic materials but also for the study of
soft matter and biological samples to reduce incoherent
backgrounds originated by hydrogen nuclei, or to apply
a spin contrast variation technique.
The first phase of our project was approved with a total budget of 133.5 BYen. It includes the linac up to 400
MeV with normal conducting cavities, the 3-GeV RCS
and the 50-GeV PS. Initially the beam energy will probably be 30-40 GeV. As for experimental facilities, the
neutron/muon hall and a half size of the nuclear and particle physics hall will be built. We have to wait for a subsequent budget for the completion of the facility. A separate budget request is submitted already this summer for
a neutrino beam line.
The construction has already started last year and the
accelerator components have been ordered. The ground
breaking ceremony is planned for this fall. The project
team is now busy with designing experimental facilities
and beamlines aiming for the completion at the end of
FY2006 and we expect first beam in 2007. We anticipate
that the rated full beams will be delivered soon after the
accelerator commissioning.
SUMMARY
JHF will be a unique high-intensity proton machine facility in the world with the 3-GeV RCS for neutron and
muon sciences and the 50 GeV PS for particle and nuclear physics. In the future an R&D facility for nuclear
transmutation (ADS) is also planned at the 600-MeV extension of the linac. This accelerator complex was realized as the joint project of two laboratories with activities in some common and distinct research fields. JHF
aims for an international research center which is open
to world-wide users. We also seek international cooperation at the facility construction phase. For example, we
are recycling the retired magnets etc. from facilities all
over the world, for their next active life at JHF.
ACKNOWLEDGMENTS
Sciences with muons
I would like to thank all members of the project team of
KEK and JAERI for daily discussions and providing me
with materials for this talk.
Muon beams are also powerful tools in the material science. The muon spin rotation (fiSR) is an established technique today at meson factories. Another very
promising application will be the production of ultraslow muon which can be accelerated to a beam with very
small emittance. The muonium dissociation from material into vacuum with thermal energy and the subsequent
laser ionization has been tested at KEK. One of the most
interesting applications of negative muons is the muon
catalyzed fusion. A negative muon can catalyze many
times of D-T fusion in cycles through the resonant formation of a D-T molecular state. There is long history of
this research, and JHF will contribute to further advancements in this field.
REFERENCES
i.
2.
3.
10
The Joint Project for High-Intensity Proton Accelerators;
KEK Report 99-4, JAERI-Tech 99-056, JHF-99-3; July
1999.
Proceedings of the International Workshop on JHF
Science; edited by J.Chiba et a/., KEK Proceedings 98-5,
JHF-98-2, 1998.
Y. Mori, "JHF machines", Talk in this workshop.