The Joint Project for High-Intensity Proton Accelerators · The 600-MeV proton beam will be used...

The Joint Project for High-Intensity Proton AcceleratorsThe Accelerators for the Joint ProjectNeutron and Muon Beam Lines at the 3-GeV PSNuclear and Particle Physics at the 50-GeV PSJAERI and Tokai SiteAccelerator Driven Transmutation Facility

1 KEK News Vol.4, No.2

The Joint ProjectKEK News

The Joint Project for High-Intensity Proton Accelerators

KEK and JAERI (the Japan Atomic Energy Research Institute) have been proposing to constructnew high-intensity proton accelerators at the JAERI Tokai site (~80 km north-east of KEK) since1999. The project is to pursue frontier science in particle physics, nuclear physics, material science,life science, and nuclear technology, using a new proton accelerator complex at the world-highestbeam power.

Originally, KEK had a hadron accelerator project called the Japan Hadron Facility, (50-GeV pro-ton synchrotron and a 3-GeV booster ring where the projected power of the latter was 0.6 MW).JAERI had a high-power spallation neutron source project with a proton linear accelerator (Linac),(3-MW pulsed beams for neutron scatterings and 5-MW continuous beams for nuclear transmuta-tion). Since both projects had a common goal to attain high-power proton beams, they were com-bined into one Joint Project.

The proposed accelerator complex consists of 1) 400-MeV (mega-electron volts) normal-conducting Linac, 2) 600-MeV superconducting Linac to increase the energy from the 400 to 600 MeV,3) 3-GeV Proton Synchrotron (PS), and 4) 50-GeV PS.

The 400-MeV protons are partly injected into the 3-GeV PS and partly into the 600-MeV Linac.The 600-MeV proton beam will be used for the basic research for nuclear waste transmutation con-verting long-lived radioactive nuclides into short-lived or non-radioactive nuclides. The main part

Muon Science µSR, high-Tc superconductor, Muonium, µCF

Various secondary beams produced with high-intensity proton beamVarious secondary beams produced with high-intensity proton beam

π

K

Neutrino (ν)Proton (p)

Target Nucleus

Muon (µ)Production of high-intensity pulsed muon beamsfrom pion decay

Radioactive NucleiSeparation and accelerationof various radioactive nucleiproduced with 3-GeV proton beam

π → µν

Proton (p)3 GeV, 50 GeV

Neutron (n)

p

Neutron ScienceMagnetism, Fractals, Polymers, Structual Biology

Beams of Short-Lived NucleiNuclear astrophysics, Super-heavy element,

Neutron (n)High-intensity pulsed spallation neutron sourceproduced with 3-GeV 333-µA proton beam

Nuclear Transmutation

Nuclear/Particle PhysicsHypernuclei, Mesons in Nuclear Matter,Neutrino Oscillation, K Rare DecaysAntimatter

KEK News Vol.4, No.2 2

of the 3-GeV proton beam will be delivered to the neutron/meson facility where extensiveresearch programs on nuclear/particle physics, condensed matter physics, material sciences andstructural biology will be carried out by using beams of muon and neutron. A part of the 3-GeVbeam will be transferred to the 50-GeV PS. At the 50-GeV PS, nuclear/particle physics experi-ments using kaon beams, anti-proton beam, neutrino beams, and primary proton beams areplanned.

Japan is expected to take a significant leadership role in accelerator science in the 21st centuryusing this facility; the present neutron source facility will be one of three major centers(Asia/Pacific rim, Europe, and North America) in the world, which were strongly recommendedfor immediate construction by the OECD Mega Science Forum for neutron sources. The OECDMega Science Forum for nuclear physics also emphasized the scientific importance of the 50-GeVPS as a world center for future hadron physics.

Phase 1 of the Joint Project was approved very recently including construction of 400-MeVLinac, 3-GeV PS, 50-GeV PS, major part of the 3-GeV neutron/meson facility, and a portion of the50-GeV experimental facility. We plan to complete it within 6 years.

KEK NewsThe Joint Project

400MeV Linac(normal conducting)

600MeV Linac(superconducting)

Neutrino toSuper-Kamiokande

3GeV Synchrotron (PS)(333mA, 25Hz)

50GeV Synchrotron (PS)(15mA)

R&D for Transmutation

3 GeV Experimental Facility

50 GeV Experimental Facility

The author of this article, Professor Shoji NAGAMIYA, is the projectdirector of the Joint Project.



The Accelerators for the JointProject

Toward the frontier of the world-highest beam power, the present accelerator technology doesnot surely guarantee the proton beam power beyond 1 MW. Among the three spallation neutronsource projects in the world, the present design of the Joint Project is going to use the concept(page 1) of the accelerator complex comprising a linac, a rapid-cycling booster synchrotron (RCS),and a main proton synchrotron, while other two facilities will use a concept of full-energy linac (1-GeV class) and storage ring.

Some of the difficulties to realize the several-GeV RCS are summarized in the following. Sincethe number of protons accelerated at one time in a synchrotron is limited by the Coulomb force, theacceleration cycle of the synchrotron should be increased (up to 25 cycles per second in the presentdesign) in order to obtain the high beam current required. The rapid cycling of the synchrotronimplies rapid acceleration of the beam. The beam is accelerated by radio-frequency (RF) electricfield. The rapid acceleration requires that the higher voltage per unit length (electric field) shouldbe applied to the beam. For a realistic design of the present RCS, one needs a field of ~50 kV/m,which is not feasible with a conventional ferrite-loaded RF cavity. Since the increase in velocityof the particles is faster, the circulating period ofthe beam in the ring is shorter. So, the other dif-ficulty is that the frequency of the RF cavityshould be adjusted rapidly to follow this rapidchange.

Recently, KEK has solved both of these prob-lems by developing an RF cavity loaded with anew type of magnetic alloy (MA) such asFINEMET. The MA-loaded cavity should with-stand over 100 kV/m, and no tuning is neces-sary. The cavity has already been power-testedup to 50 kV/m, and has been beam-tested invarious ways.

The construction of the low-enegy front (60MeV) of the proton linac started in 1998. Thelinac comprises a volume-production type ofnegative hydrogen ion source, a 3-MeV radio-frequecy quadrupole (RFQ) linac, a 50-MeVdrift-tube linac (DTL), and a 60-MeV separatedDTL (SDTL). The SDTL will be extended up to The MA-loaded cavity



200 MeV in the Joint Project linac, followed by the annular-ring coupled structure (ACS) up to 400MeV.

The RFQ linac is well field-stabilized by π-mode stabilizing loops (PISLs) devised in KEK. Theprototype of the 3-MeV RFQ linac with PISLs had been beam-tested several years ago, acceleratingan H− beam of 13 mA in peak. The design beam current of the present one is 30 mA. The SDTLdevised in KEK has excellent power efficiency over the conventional DTL. The ACS is axially sym-metric in contrast to the commonly used side-coupled structure, which is axially asymmetric.Because the axial symmetry is one of important factors in order to reduce the beam loss, the ACShas been studied and realized in KEK first. The several prototypes of the ACS have already beenpower-tested.

The conventional acceleratortechnology is not sufficient for real-izing the proposed beam power.For this reason, the results of manyinnovations have already beenincorporated for the Joint Projectaccelerators in order to push for-ward the beam power front of theaccelerator technology. Yet, furtherdevelopment will be necessary torealize the challenging features ofthe Joint Project.

Young, ambitious scientists andengineers are thus invited to jointhe project.

The author of this article, Professor Yoshishige YAMAZAKI, has been thegroup leader of the accelerator group in the Joint Project.

RFQ installed in a tunnel in KEK



Neutron and Muon Beam Linesat the 3-GeV PS

Neutron Science

Neutron gives very important information of atomic structure and dynamics of material inmicroscopic scale, even of magnetic ones, which is indispensable to understand properties andfunctions of material, and leads to improvement of material's function and invention of new mate-rials. The neutron facility in the Joint Project is a pulsed spallation neutron source and creates veryintense neutrons in very wide range of energy from µeV to MeV region. Therefore, there are hugevariety of application with neutron from the facility forstudying materials, ranging from bio-molecules, organic/inorganic chemical molecules, medicines, food artifacts,ferro-electrics, magnets, semiconductors, superconductors,electric/fuel battery materials, glasses, amorphous, liquids togases, and even for study on fundamental physics. It will bealso used for diagnostic investigation of products of industry,and for archaeology purpose by using radiographic method.

Here, we demonstrate two scientific examples, which willbe performed in the neutron facility of the Joint Project.

a. High-Tc superconductor

Superconductivity of oxide-high-Tc superconductoroccurs in the two dimensional Cu-O2 plane. Hence, studieson the spin-spin correlation, charge-lattice interaction in the

plane as well ascrystal structureare indispensableto elucidate themechanism.

b. Structure and dynamics of bio-molecules

It has been understood that the function of proteinis activated when its shape is unfolded in a water solu-tion. This problem is called folding-unfolding prop-erty of protein. A certain kind of dynamics has alsoimportant role for the function. Neutron can study themechanism of functionality of protein.Protein structure and water molecule

CuO2

O

PlaneY

Ba

Cu

Crystal structure of a high-Tcsuperconductor YBa2Cu3O7



Muon Science

"Muon Science" is the research program to develop the application of muon, an elementaryparticle obtained by the natural decay of a pion, which will be mass-produced with unprecedentedintensity in the planned facility. While the use of positively charged muon as a hydrogen isotopewith ultrahigh sensitivity is rapidly growing in material research, the negatively charged muon isdrawing wide interest as a smart catalyst of d-t nuclear fusion at low temperature. The programcovers various research fields including the study on the microscopic origin of distinct materialproperties such as high-Tc superconductivity and magnetism, the structure and dynamics ofhydrogen isotopes and their environment in various semiconductors and organic materials. Inparticular, the realization of ultra-slow muon beam will facilitate much wider application of muons.

The author of this article, Professors MasatoshiARAI (left) and Ryosuke KADONO (right), areworking in Neutron Science and Muon Science,respectively, at KEK.

Mu @Td

Ga N Mg

H

Ga

Blue LED

Positive muons simulate the state of the hydrogen (Mu) in semiconductors and provide detailed microscopicinformation.



Nuclear and Particle Physics atthe 50-GeV PS

In nuclear and particle physics, one of current interests is to study the origin of mass. One isrelated to the mass of matter. It is known that over 99% mass of the matter is carried by atomicnuclei. A nucleus is an assembly of protons and neutrons. Each proton or neutron is made ofthree quarks. One puzzle which has not been solved quantitatively until now is that the mass ofproton (or neutron) is ~1 GeV/c2, whereas the constituent quark mass is less than 1/100 of theproton mass. It is believed that the creation of a large proton mass is due to the symmetry break-ing (called the chiral symmetry breaking), while a quantitative nature of this symmetry breakinghas not been studied well. Theoretically, it is expected that the quantitative aspect of the symme-try breaking can be studied by inserting a meson (which is made of quark and anti-quark) or abaryon (which is made of three quarks) in the interior of extreme conditions and by studying thechange of its mass.

One approach is to implant mesons or baryons in the interior of nuclear matter. Restoration ofsymmetry breaking is expected theoretically, so that the mass of meson or baryon would bereduced in these extreme conditions.

The other is related to the mass of neutrino. From the most fundamental principle, there areno reasons to prohibit a neutrino from having a mass, although it has been believed for manyyears that the neutrino has zero mass. In a recent experiment at SuperKamiokande, it was demon-strated that muon neutrinos (νµ) from the sky (which is called the atmospheric neutrinos) might beconverted to another type of neutrinos called tau neutrinos (ντ) while traversing through the Earth.

e+

e-

Vector MesonsHyperon

Implantation of Baryon and Meson

Normal Nucleus


This phenomenon is called the neutrino oscillation and it can occur only when the neutrinocarries a mass. In order to pin down this observation at the SuperKamiokande, it is planned at theJoint Project to produce νµ beams from the 50-GeV PS and to measure the νµ flux both at the imme-diate exit of the accelerator and at the site of SuperKamiokande which is located at a distance of300 km from the Tokai site. This type of experiment is already conducted at KEK by having νµ

beams from the 12-GeV PS. Our Joint Project, however, can produce high-flux neutrino beamswith intensity of more than 100 times of the neutrino flux present KEK facility can provide. Thus,a higher accuracy experiment on the origin of the neutrino mass can be done at the Joint Project.


The author of this article, Dr. Tomofumi NAGAE, is working in NuclearPhysics at KEK, and a member of the Project Office.



JAERI and Tokai Site

Japan Atomic Energy Research Institute (JAERI), a core institute of comprehensive nuclearenergy research in Japan, was established in June 1956. Since then, JAERI has endeavored to be apioneer in the nuclear field by engaging in advanced research and development activities, whichare conducted at the six research establishments, i.e., Mutsu-, Tokai-, Naka-, Oarai-, Takasaki-, andKansai Research Establishments, along with Tokyo Headquarters.

Currently, the JAERI's major research activities include: (1) completion of construction of theHigh Temperature Engineering Test Reactor at the Oarai, (2) research and development of anuclear fusion reactor at the Naka, (3) promotion of neutron science research at the Tokai, (4)research of advanced photon science such as X-ray lasers at the Kizu site of the Kansai, (5) radia-tion application research (mainly ionirradiation research) at the Takasaki,(6) promotion of the most advancedbasic research in the nuclear field atthe Tokai directed by the Headquar-ters, and (7) synchrotron radiationresearch using SPring-8 (Super Pho-ton Ring 8 GeV) at the Harima site ofthe Kansai.

The facility complex of the JointProject will be constructed in theTokai Research Establishment locatedin Tokai-Mura, 80km north-east ofKEK and faces to the Pacific Ocean asshown here.

The author of this article, Dr. Yukio OYAMA, is the co-leader of theNeutron group of the Joint Team, and the deputy director of Center forNeutron Science of JAERI.

Site forJoint Project

Site forJoint Project

Pacific Ocean

Tokai Research Establishment of JAERI


Accelerator DrivenTransmutation Facility

Nuclear energy system can not be completed without establishing its nuclear waste manage-ment system. Although it has been addressed that the principle scenario of the waste stream inJapan is the deep land burial of high level waste (HLW), the HLW still remains as potential haz-ards. Accordingly, it is encouraged to pursue a way to reduce HLW to mitigate a potential load ofthe waste management. The accelerator driven system (ADS) has been recognized world wide asan attractive option for the nuclear transmutation of HLW. Japan Atomic Energy Research Institutehas proposed an ADS concept for the nuclear transmutation of HLW. With the ADS, a hazard levelof HLW is estimated to be reduced to 1/200 comparing to a case without the ADS in 500 years.

To realize ADS, we have to do various areas of fundamental researches and technical develop-ments. They are the spallation target technology, the sub-critical reactor physics, a hybrid systemoperation and controls, the nuclear transmutation process, etc. Among those, the development ofthe material for the spallation target and the sub-critical reactor physics driven by the high-energyproton beam are the most important issue to evaluate the technical feasibility for the ADS. In orderto make a breakthrough in ADS technology development, we are proposing two experimentalfacilities to be built under this JAERI-KEK joint project. They are (1) Accelerator Material Irradia-tion Facility, and (2) ADS Physics Experimental Facility. The former is aiming at evaluating sound-ness of the materials, which are exposed by extremely severe proton and neutron irradiation undera high temperature lead-bismuth flow. The proton beam of 600 MeV and 0.33mA (200 kW) isused. The latter facility is for researches of the basic sub-critical reactor physics, e.g., sub-critical-ity, reactivity, power profile, etc. and reactor power control with the beam power, with a lowpower proton beam of up to 10 W.

We do believe that the basic experiments for ADS under the joint project will enrich ourknowledge and will be the first and a great step toward a new horizon of the nuclear energy sys-tem in the 21st century.


The author of this article, Dr. Yujiro IKEDA, is the leader of NeutronicsGroup of JAERI, and also is the leader of ADS Nuclear TransmutationExperimental Group under the Joint Project.


KEK News

Inden “ ”

“Inden” is a method to preparedeer skin on which fine patterns areprinted using Japanese lacquer madeof sap from a lacquer tree “Urushi”.For many centuries, Urushi has beenwidely used to protect surfaces fromabrasion and weather. It was alsoused to decorate armor for Japaneseworriers, “Samurai”.

Inden is one of the classic Japan-ese crafts. The name “Inden” is anabbreviation of “Indo-denrai” where“Indo” means “India”‚ “denrai” means‚“learned from” in Japanese, hence itmeans “an art learnt from India”.

Ancient Japanese learned from India all sorts of things such as Buddhism as well as other artsand crafts. I have asked an Indian physicist if he knew anything similar in India. He immediatelybrought me a beautiful silk cloth that shows quite similar pattern (Keri pattern) to a traditionalInden pattern. He also mentioned that his wife had seen similar patterns printed on leather insouth India. International relations between Japan and India goes back over 1000 years (throughChina in most cases). KEK now have various collaborations with Indian physicists.

The art of producing Inden isslowly disappearing as modern mate-rials are taking over the market. Mr.Masayoshi Nishitoge is one of theforerunner of the art actively produc-ing the Inden products although he isalready at the age of 88.

He himself invented various tech-niques to make the Inden productavailable to customers at competitiveprices. He is the one who establisheda technique to prepare deer skin to bea practical chamois cloth.

Deer skin, all of which he is get-

People

Various Inden patterns by Mr. Nishitoge

One of Indian patterns, Keri


KEK News

ting from China now, is tannedand smoked.

Only the middle layer betweenthe outer and inner surface of deerskin is used. It takes three monthsto be ready for the final printingstage. The finished Inden has deli-cate soft texture that man madematerials can not quite compete,yet has durability for daily use.

Mr. Nishitoge has been intro-duced in several books and news-papers for his excellence. It isgratifying to know that there aremany places in Japan where tradi-tional method is more valued over modern method.

Last year, the year of dragon, Mr. Nishitoge made a framed large Inden piece with whitedragon motif and donated it to Motoise-Kono Shrine in Kyoto prefecture. It is a difficult challengeto make such a large piece without any fault as the printing is done using a paper pattern on silkscreen and the printing must be completed with a single stroke. It is his years of experience thatmade this beautiful piece possible.

people

Mr. Nishitoge at work

Inden with white dragon motif that was presented to Motoisekono Shrine

13

KEK News

KEK News Vol.4, No.2

Events

November 6-10KEK Art Festival week was lively with many

exhibitions of arts and crafts as well as a con-cert participated by a professional pianist Mr.Takashi Fujii from Germany.

November 6-15The 15th International Collaboration on

Advanced Neutron Sources was held at TsukubaInternational Congress Center. 262 participantsactively discussed about the future plan forsafe, high intensity neutron source facility.

November 11 and 18Public lecture "Where is the anti-matter - Bro-

ken symmetry" in Tsukuba.

November 14 through 17The 6th KEK-SLAC ISG Meeting on linear

colliders was held in KEK. Participants fromUSA(SLAC, LBNL, LLNL), Russia and Japanexchanged ideas actively.

December 6Prof. Akira YAMAMOTO of KEK Cryogenic

Center received Nishina Memorial Prize for hiswork on observation on anti-protons with asuperconducting magnet.

December 21 and 22The 5th IHEP/KEK Collaboration Meeting

was held in IHEP, Beijing, China.

December 26ATLAS Central Solenoid (superconducting)

was tested and successfully worked under8400A which is the highest required current forthe solenoid.

14

KEK News

KEK News Vol.4, No.2

Events

Picture on front coverThe front cover shows one of the Buddhism statue, Ashura, of Kofukuji Temple in Nara. (8th century) With the 6 armsand three faces, the Ashura handles all sorts of situations just like the several beam line branches of the HighIntensity Proton Accelerator complex. The Ashura is believed to have originated from India. The three faces look ateverywhere, while the Accelerator complex looks at KEK, Tokaimura and Kamioka. I thought the coincidence isinteresting. We thank people in Kofukuji very much for their understanding and support.

Picture on back coverThe building in Hiroshima was within 600m from the A-bomb explosion on August 6, 1945. It was registered on theUNESCO World Heritage. At the entrance to the 21st century, it stays as a reminder to physicists that physics cancreate something that may not be good for the creatures on the Earth. A museum is near by which tries to promotepeace and to reduce hatred. We appreciate the museum very much for their help.

Readers commentAn ex-staff member of INS sent the editor a comment on Vol.3, No.2, saying that it should have been noted that the350MeV electron storage ring of INS-ES was the first facility dedicated only for synchrotron light users. Editor welcomes readers comments as it would make the publication better.

January 4, 2001KEK Director General, Hirotaka SUGAWARA

gave a speech on new years resolution all inEnglish, showing his strong intention to makeKEK more user-friendly to international com-munity. His strong will to promote liner col-lider project was the main theme. (Visit KEKweb site for the full text of his speech)

January 6, 2001As a part of Japanese government reorgani-

zation, former Ministry of Education (Mon-busho) and former Science and TechnologyAgency were merged into one governmentorganization, Ministry of Education, Culture,Sports, Science and Technology.

February 4, 2001Mr. Katsuhiro MIMORI of KEK was the third

in Masters Marathon Championship (age 60-64class) held in Saitama pref. He also was the 7thto reach the goal in Boston Marathon (SeniorDivision) held on April 17th, 2000.

February 9, 2001KEK International Party 2001 was organized

by non-Japanese physicists and their familymembers. 54 people from 12 countries (11 fromRussia, 3 from Sweden, 4 from USA, 4 fromBangladesh, 4 from India, 2 from China, 2 fromKorea, 1 from Myanmar, 1 from Canada, 2 fromFrance, 1 from UK, 1 from Vietnam, 1 fromAustralia, 18 from Japan) attended. The partywas further enhanced by all sorts of dishes oftheir own countries prepared by the partyattendants.

KEK News Vol.4, No.2 March 2001

Published by High Energy Accelerator Research Organization1-1 Oho, Tsukuba, Ibaraki, 305-0801 Japan

Printing and cover design : Matsueda Printing Inc.2438 Tenmancho, Mitsukaido, Ibaraki, 303-0034 JapanEditor : Tokio K. OHSKA, e-mail: [email protected]

Please send comments to : KEK International Affairs Division1-1 Oho, Tsukuba, Ibaraki, 305-0801 Japan

telephone +81-298-64-5130, telefax +81-298-64-5195e-mail [email protected]

The Joint Project for High-Intensity Proton Accelerators · The 600-MeV proton beam will be used...

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