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This correpondence examines issues observed in "Commentary: The responsibility of the Japanese media, the Fukushima accident and the use of personal data'' by T. Sawano et al., published in QJM. from the points of view of scientific and factual recognision of the situation and issues related to legal scheme and research ethics addressed in the Commentary.

We point out that the recently published Publisher’s Note concerning two retractions in Journal of Radiological Protection and the retraction notices contain various incorrect statements, misrepresentations of facts and omission of important events.

Using 58 million J / ψ decays obtained by BESII, a charged κ particle is observed in the analysis of the K S π ± system recoiling against K ⁎ ( 892 ) ∓ selected in J / ψ → K S K S π + π − . The mass and width values of the charged κ are obtained to be ( 826 ± 49 − 34 + 49 ) MeV / c 2 and ( 449 ± 156 − 81 + 144 ) MeV / c 2 for the Breit–Wigner parameters, and the pole position is determined to be ( 764 ± 63 − 54 + 71 ) − i ( 306 ± 149 − 85 + 143 ) MeV / c 2 . They are in good agreement with those of the neutral κ observed by the BES Collaboration.

Experiments for the laser guiding studies has been carried out with the 30-fs 100-TW Ti:sapphire laser pulse interaction with the underdense plasma produced by a long-slab (1.2 times 10 mm2) gas jet and an ablative laser-triggered discharged capillary. Formation of an extremely long plasma channel with a length (~10 mm) 10 times above the Rayleigh length is observed when the laser pulse power is much higher than the critical power for relativistic self-focusing. The long-self-guiding- channel formation is accompanied by the electron acceleration with a low transverse emittance (< 0.87pi mm mrad) and high electric current (~10 nC/shot), as well as the generation of a quasi- monoenergetic electron bunch with an energy of ~80 MeV. In order to continuously elongate the plasma channel, a 4-cm- scale discharged capillary was used. We successfully demonstrated laser-plasma acceleration of high-quality electron beams up to nearly semigigaelectronvolts. Our results exactly verified the prediction of laser wakefield acceleration through a centimeter- scale plasma channel in the "blowout bubble" regime, where a microscale plasma cavity produced through the ultrarelativistic laser-plasma interactions plays an essential role in the self- injection and acceleration of electrons.

Based on 58 million BESII J / ψ events, the K ¯ ∗ ( 892 ) 0 K + π − channel in K + K − π + π − is studied. A clear low mass enhancement in the invariant mass spectrum of K + π − is observed. The low mass enhancement does not come from background of other J / ψ decay channels, nor from phase space. Two independent partial wave analyses have been performed. Both analyses favor that the low mass enhancement is the κ , an iso-spinor scalar resonant state. The average mass and width of the κ in the two analyses are 878 ± 23 −55 +64 MeV / c 2 and 499 ± 52 −87 +55 MeV / c 2 , respectively, corresponding to a pole at ( 841 ± 30 −73 +81 ) − i ( 309 ± 45 −72 +48 ) MeV / c 2 .

An overview of the KEKB accelerators is given as an introduction of the following articles in this issue, first by summarizing the basic features of the machines, and then describing the improvements of the performance since the start of the physics experiment.

KEKB has been operated since December, 1998, to deliver BB pairs for a physics detector. In this paper,we describe the commissioning procedure of KEKB.

Using modularized NaI(Tl) detectors, we carried out a high-statistics measurement of inclusive π o and η spectra in antiproton annihilation at rest in a liquid D 2 target. We obtained the following two-meson yields (branching ratios) per \bar p N ( N = p or n ) annihilation: 0.19± 0.09% for π o ω, 1.07±0.19% for π o ρ o , 0.057±0.018% for π o η, 0.0123±0.0055% for π o π o , 0.02±0.02% for π o ρ - , 0.202±0.031% for π o π - , 0.49±0.12% for ηω, 0.45±0.15% for ηρ o , and 0.91±0.22% for ηρ - .

A signal-processing system based on two-tap digital filters has been systematically studied considering its application to bunch feedback systems. Through studies we have found that the two-tap-filter-based system is a hopeful candidate for the signal processor used in high-speed, large-scale bunch feedback systems.

Using modularized NaI(Tl) detectors, we carried out a high statistics measurement of inclusive \ensuremath{\gamma}-ray, ${\ensuremath{\pi}}^{0}$, and \ensuremath{\eta} spectra, and determined the branching ratios or upper limits of Pontecorvo reactions $\mathrm{p\ifmmode\bar\else\textasciimacron\fi{}}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n$, ${\ensuremath{\pi}}^{0}{\ensuremath{\Delta}}^{0}$, $\ensuremath{\eta}n$, and $\ensuremath{\eta}{\ensuremath{\Delta}}^{0}$ from the corresponding monochromatic peaks in them. The obtained branching ratios are $B(\mathrm{p\ifmmode\bar\else\textasciimacron\fi{}}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n)=(1.03\ifmmode\pm\else\textpm\fi{}0.41)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $B(\mathrm{p\ifmmode\bar\else\textasciimacron\fi{}}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\Delta}}^{0})=(4.67\ifmmode\pm\else\textpm\fi{}1.66)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $B(\mathrm{p\ifmmode\bar\else\textasciimacron\fi{}}d\ensuremath{\rightarrow}\ensuremath{\eta}n)l8.94\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ (95% C.L.), and $B(\mathrm{p\ifmmode\bar\else\textasciimacron\fi{}}d\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\Delta}}^{0})l6.49\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ (95% C.L.).

Using modularized NaI(Tl) detectors, we have carried out a high-statistics measurement of inclusive {gamma}-ray spectra from {ital {bar p}d} annihilation at rest separately for each charge multiplicity of the final state. We have not seen, at statistical significance above 4{sigma}, any monochromatic {gamma}-ray peaks, which may be assigned to baryonium production {ital {bar p}p} or {ital {bar p}n}{r arrow}{gamma}{ital B} or to {ital {bar N}NN} bound-state production {ital {bar p}d}{r arrow}{gamma}({ital {bar N}NN}). The 4{sigma} upper limit for baryonium production per annihilation varied between 10{sup {minus}2} and 10{sup {minus}4} depending on baryonium mass of 1700 to 600 MeV/{ital c}{sup 2} and on the charge multiplicity. At (2--3){sigma} levels, however, five peaks were observed and three of them are located at the same position with the similar (2--3){sigma} peaks observed in {ital {bar p}p}{r arrow}{gamma}{ital B} and {ital {bar p}p}{r arrow}{pi}{sup 0}{ital B}.

KEK has proposed to build an accelerator test facility (ATF) capable of producing a 2.5 GeV electron beam for the purpose of stimulating R&D for linear colliders in the TeV region. The ATF consists of a 1.54 GeV S-band linear accelerator, a 1.54 GeV damping ring and a 1.0 GeV X-band linear accelerator. The ATF project will be carried out in three phases. In phase I and phase II the S- and X-band linacs will be constructed, respectively, and in phase II the damping ring will be completed. The construction of ATF phase I has started, and the 0.3 GeV S-band injector linac is almost complete. The heart of the control system for the phase-I linac is based on two microVAX systems. At present these computers are connected to the KEK network (Ethernet). A CAMAC-enhanced byte-serial highway extends to the controlled equipment. Optical-fiber cables are used for the serial CAMAC highway in order to obtain high reliability in a noisy environment. The transmission rate on each optical fiber in 5 Mbyte/s. In this paper we present the status of the control system of the phase-I linac and the design of the computer control system for the ATF.

Coupled bunch instability caused by electron cloud has been observed in the KEKB-LER. Time evolution of the instabilities just after the turning-off the transverse bunch feedback have been recorded with several solenoid-field conditions to suppress the blowup due to electron cloud. The mode spectra of the coupled-bunch instabilities have been compaired with the simulations of electrons moving in drift space, weak solenoid field and strong bending field.

A coupled-bunch instability caused by an electron cloud has been observed in the KEKB LER. The time evolution of the instabilities just after the turning-off the transverse bunch feedback was recorded with several weak solenoid-field conditions, which are used to suppress the vertical blowup of the beam size due to the electron cloud. The mode spectra and their growth rates of the coupled-bunch instabilities were compared with simulations of electrons moving in drift space, a weak solenoid field, and a strong bending field. Mode spectra without a solenoid field support the model where the instability is dominated by the electron clouds in the drift space with a lower secondary yield of photoelectron ${\ensuremath{\delta}}_{2,\mathrm{max}}=1.0$ rather than 1.5. With the solenoid field, the behavior of unstable modes and the growth rate with the strength of solenoid field also support the simulation with lower secondary emission yield.

An electron cloud induces a wake force on a charged particle beam which creates correlations between bunches---i.e., a small displacement of a bunch creates a perturbation of the electron cloud, which affects the motions of the following bunches, with the result that a coupled-bunch instability is caused. The coupling mode of the instability is determined by the motion of the electrons in the cloud---that is, it depends on which electrons, moving in a drift space, a weak solenoid field or a strong bending field, are dominant for the instability. We discuss the coupled-bunch instability focusing on the relation between the mode spectrum and the electron motion.

The Japan National Laboratory for High-Energy Physics (KEK) has proposed building a Test Accelerator Facility (TAF) capable of producing a 2.5 GeV electron beam for stimulating R&D for a linear collider in the tera-electronvolt region. The TAF consists of a 1.5 GeV S-band linear accelerator, a 1.5 GeV damping ring, and a 1.0 GeV X-band linear accelerator. The TAF project will be carried forward in three phases. Through phase-I and phase-II, the S-band and X-band linacs will be constructed, and in phase-III, the damping ring will be completed. The construction of TAF phase-I has started, and the 0.2 GeV S-band injector linac is almost complete. The phase-I linac is composed of a 240 keV electron gun, subharmonic bunchers, prebunchers, and a traveling buncher followed by high-gradient accelerating structures. >

Ten years have passed since the current control system started the operation of the TRISTAN accelerator. The system uses CAMAC as a front-end electronics, and they are controlled by 25 Hitachi process computers linked by a N to N token ring network. In order to have the ability to perform complicated accelerator operations, there is a strong request to renew these 25 process computers. Firstly, we review how we will rejuvenate the current control system under some constraints, such as the lack of man-power, limited time and financing. This is followed by proposals for the next step of rejuvenation.

Superconducting quadrupoles for the mini-beta insertions were installed close to every interaction point and their performances were tested successfully. The system consists of four subsystems, which can be operated individually at the local control rooms located near the subsystems and/or at the remote central cryogenic control room. >

A vertical coupled-bunch instability was observed for a positron beam at the Beijing Electron Positron Collider (BEPC). The experimental results show that the instability has similar characteristics as that observed in the Photon Factory of KEK several years ago. The instability at BEPC can be explained by the effect of an electron cloud which is produced in the beam chamber by synchrotron light hitting the wall.

An experiment was carried out in TRISTAN AR for the search of the fast beam-ion instability (FBII). A train of 100 bunches with 2 ns spacing was stored with the help of the transverse bunch feedback system. The nitrogen gas was intentionally leaked into the inside of the vacuum duct to enhance the ion effect. The oscillation patterns were recorded by the beam position monitor system which is capable of storing the transverse position of every bunch up to 1600 turns. The spectra of the bunch oscillations were also measured by a spectrum analyzer. This paper describes the results of the experiment and also discusses the possible explanation of them in terms of the FBII.

A vertical coupled bunch instability explained as the photoelectron instability (PEI) was observed in the photon factory at KEK. To further investigate the instability, the experiments on the PEI have been carried out in Beijing Electron Positron Collider (BEPC) with the collaboration between MEP, China and KEK, Japan. Many interesting phenomena have been observed for different sets of parameters.

The KEKB project, constructing an asymmetric electron-positron collider for B physics in Japan, has officially approved and has started in 1994. The goal of the KEKB accelerator control system is to provide a powerful, flexible, and extendible control system for both accelerator physicists, who need beam information and are not so patient, and operators, who control all equipment. To achieve this goal on schedule, we decided to use standard technology where it is applicable. We have studied some existing control systems based on "Standard Model" of the modern accelerator control systems, such as EPICS or V-system, as a framework of the control system and have chosen the base of the control system according to this study. Another key issue in the KEKB accelerator control system is use of database management system for unified management of the information which the control system requires. Integration of control system with the modeling software, SAD, is also discussed.

A photoelectron-trapping phenomenon has been found in the simulation of the photoelectron cloud. It is found that the photoelectrons can be trapped in the quadrupole and sextupole magnetic fields for very long time until it longitudinally drifts out of the magnets, even a long bunch train separation is not sufficient to clear up the photoelectrons. Therefore, such a kind of long time trapped photoelectron cloud can cause coupled bunch instability. The trapping phenomenon is strongly beam dependent, especially on the bunch length. There is no such kind of trapping if the positron beam does not disturb the photoelectrons during the whole process. There is also no trapping for positron bunch with bunch length longer than the period of the photoelectron's gyration motion at the mirror points. The trapping is a mirror field trap which is caused by beam disturbance. The trapping phenomenon and mechanism will be presented in detail.

An experiment investigating the photoelectron instability has been performed in BEPC at IHEP, China. The betatron oscillation of each bunch was observed and recorded by a single pass beam position monitor system which has a capability to measure the transverse position of every bunch over 16000 turns. The effect of an octupole magnet on the instability was also studied. This paper describes results of those observations and analyses.

The commissioning of the KEKB B-Factory storage rings started on Dec. 1, 1998. The two rings both achieved a stored current of over 0.5 A after operating for four months. The two beams were successfully collided several times. The commissioning stopped on Apr. 19, taking a 5-week break to install the Belle detector.

KEKB has been operated since December, 1998, to deliver B ¯ B pairs for a physics detector. In this paper,we describe the commissioning procedure of KEKB.

The machine commissioning of KEKB started in December 1998 and its operation was terminated at the end of June 2010 to upgrade KEKB to SuperKEKB. In this paper, we summarize the history of KEKB and show the achievements made there.

Due to their detrimental effect on the experimental detector of the KEK B-Factory, the leakage fields of the bending magnets, which will be installed near to the collision point, need to be as small as possible. For achieving this smaller leakage field, we propose a special superconducting dipole with a shield coil. A novel approach for achieving a leakage field of less than 5 mT at a radius of 200 mm, based on an active shield method, has been investigated. The design concept of the coil, which consists of a main coil and a shield coil having an opposite current to the main coil, has been developed. The coil design and the structure of the magnet are described.

The B-Factory project at KEK aims to construct an accelerator complex to detect the CPviolation effect of B-mesons. It is a two-ring electron-positron collider of 3.5 × 8 GeV in the existing TRISTAN tunnel. The design peak luminosity is 1034 cm−2s−1, which will be realized in two steps: from a small-angle collision with a luminosity of 2 × 1033 cm−2s−1 to a large-angle crab-crossing scheme with the final luminosity of 1034 cm−2s−1.

A high-quality electron beam with a central energy of 0.56 GeV, an energy spread of 1.2% rms, and a divergence of 0.59 mrad rms was produced by means of a 4 cm ablative-capillary-discharge plasma channel driven by a 3.8 J 27 fs laser pulse. This is the first demonstration of electron acceleration with an ablative capillary discharge wherein the capillary is stably operated in vacuum with a simple system triggered by a laser pulse. This result of the generation of a high-quality beam provides the prospects to realize a practical accelerator based on laser-plasma acceleration.

The present machine design of the future asymmetric B‐factory at KEK is reviewed. Beam energies and a design luminosity are chosen as 8×3.5 GeV2 and 1×1034/cm2/sec in due consideration of requirements from physics experiments. In the design, it is aimed to squeeze the vertical beta‐function at IP (β*y) to 1 cm. The beam‐beam limit is assumed to be 0.05 with the requirement that the bunch length should be half of β*y, i.e., 0.5 cm. Flat beams are chosen. In order to attain the design luminosity, beam currents of 2.6 A for the 3.5 GeV ring and 1.1 A for the 8 GeV ring are necessary. An all RF buckets filling scheme and a crab crossing scheme are adopted to realize the short bunches and to decrease RF voltages. The damped cavity is adopted to suppress the coupled bunch instability. Growth rates of the instability are estimated in the case that the damped cavities are used. Further extensive studies and R&D’s are necessary to realize the design luminosity.

By using modularized NaI(Tl) detectors, we carried out a high statistics measurement of inclusive π0 spectra from p p annihilation at rest. We did not observe any narrow π0 peaks arising from baryonium production, p p →π 0 B . The σ upper limit of the yield varied between 10−2 and 10−4 depending on the mass and oncharge multiplicity. Three narrow peaks at 2 σ levels were seen at approximately the same masses as in the previous measurement of p p → γ B .We also derived the yield of p p annihilation into π0M forM = o, η′, ω, ϱ0, η and π0.

Design and performance of a superconducting high energy secondary beam line, π1, are reported. The π1 beam line was constructed to transport an 8 GeV/c unseparated secondary beam to the experimental area of the 12 GeV proton synchrotron at KEK. The beam line has been operated for five years without any serious problems and was shut down in the summer of 1986. We describe its design, construction and operational results.

The polarization of 2.4×10 5 \(\varLambda^{0}\) hyperons has been measured in inclusive production by 12- GeV protons on tungsten at three production angles, 3.5°, 6.5°, and 9.5°. In terms of Feynman's x F and the transverse momentum p T of \(\varLambda^{0}\), the kinematic range is 0.3≦ x F ≦0.8 and 0.4≦ p T ≦1.6 GeV/c. The \(\varLambda^{0}\) was identified by detecting the proton and pion from the \(\varLambda^{0}{\rightarrow}p\pi^{-}\) decay with a double-stage magnetic spectrometer, and its polarization was determined from a hybrid Monte Carlo analysis on asymmetries in the angular distribution of the decay products. The observed polarization is consistent with the data obtained at higher energies, indicating that the phenomenon of the inclusive \(\varLambda^{0}\) polarization scales down to the 12-GeV region. The polarization at 12 GeV increases linearly with p T up to 16% at p T =1.0 GeV/c, showing a tendency to level off above that point.

The design and the performance of the K3 beam at the KEK 12 GeV Proton Synchrotron are reported. The beam line provides separated kaons up to a maximum momentum of 0.8 GeV/c and separated antiprotons up to 1.1 GeV/c. The beam can be operated in two different modes: a high-intensity mode, K3-S, and a high-momentum-resolution mode, K3-L. The solid-angle momentum acceptance and the beam length of K3-S are 48.4 msr Δ PP and 14.45 m, respectively, and those of K3-L are 13.3 msr%ΔPP and 16.3 m. Measured optical parameters of K3-S agreed with the designed values. Measured intensity of K+ per 1012 protons and the π+μ+e+K ratio were 1.96 × 104 and 4.2 at 500 MeV/c, 3.12 × 104 and 3.0 at 540 MeV/c, and 5.18 × 104 and 2.6 at 600 MeV/c.

We have carried out high-statistics measurements of inclusive ..pi../sup 0/ and ..gamma..-ray spectra from p-barp annihilation at rest. From the monochromatic peaks in the ..pi../sup 0/ spectra, we derive the yield (or its upper limit) of the reaction p-barp..--> pi../sup 0/M for M = phi, eta', ..omega.., rho/sup 0/, eta, and ..pi../sup 0/. The same quantity was independently obtained from the ..gamma..-ray spectra, which included some ..pi../sup 0/'s that were mistaken as single ..gamma.. rays due to the limited granularity of the ..gamma.. detector. Taking the monochromatic peaks in the ..gamma..-ray spectra as being due to prompt ..gamma.. rays, we also derive the upper limit for p-barp..--> gamma..M.

The beam K4 is designed to transport high-intensity, high-purity antiprotons in the momentum range between 0.4 and 0.8 GeV/c. Antiprotons are separated from unwanted pions, muons, and electrons by double-stage mass separation. The solid-angle momentum acceptance of the beam is 34.1 msr % ΔP P and the beam length is 28.5 m. The measured intensities of antiprotons at 450, 500, 580 and 650 MeV/c are 100, 210, 510 and 1100 per 1012 ppp; the corresponding π − μ − e − p ratios are 13.1, 7.7, 8.8 and 22.5, respectively. About 45% of the incomming antiprotons at 580 MeV stop or annihilate in flight in liquid hydrogen contained in a target cell with the dimension of 140 mm in diameter and 230 mm in length.

We have constructed a modularized array of NaI(Tl) detectors in a half barrel configuration that is about 75 cm long with an inner radius of 25 cm. 96 NaI modules are surrounded by a layer of 48 modules of scintillating glass which have similar dimensions to the NaI modules. Each NaI crystal was shaped as a trapezoidal pyramid and encapsulated in a 1 mm thick aluminium container with dimensions of (43 × 94) × (110 × 94) × 377 mm3. The construction and performance are described along with the gain calibration and monitoring, the beam position sensitivity, the scattering between modules, etc. The fwhm energy resolution of a 5 × 5 array of NaI modules varied from 6.5% for incident electrons at 100 MeV to 3.6% at 1000 MeV

Results are presented on the effects of radiation on BGO crystals. It is shown that BGO has more than two orders of magnitude higher resistance against low energy γ rays than SF5 lead glass. Darkening of the crystal is hardly visible even after an irradiation of 3.6 × 10 6 R. The darkening faded by more than one half after several days and it has almost completely disappeared after much longer periods. The tolerable rate of synchrotron radiation on BGO calorimeters is 100 R/h in a conservative estimate if the degradation in transmittance is required to be less than 1 % over a depth of 20 radiation lengths. In BGO calorimeters, the degradation of scintillation efficiency is less important than that of the transmittance, 99.999% pure crystals have a two orders of magnitude better resistance than 99.99% pure ones. Sample darkening caused by 12 GeV protons or fast neutrons is an order of magnitude more severe than that by low energy γ rays. Moreover, the recovery is not complete even after a period of more than 100 days. Some data on sample activation are also presented.

Twenty-four minicomputers forming an N -to- N token-ring network control the TRISTAN accelerator complex. The computers are linked by optical fiber cables with 10 Mbps transmission speed. The software system is based on NODAL, a multicomputer interpretive language developed at the CERN SPS. The high-level services offered to the users of the network are remote execution by the EXEC, EXEC-P and IMEX commands of NODAL and uniform file access throughout the system. The network software was designed to achieve the fast response of the EXEC command. The performance of the network is also reported. Tasks that overload the minicomputers are processed on the KEK central computers. One minicomputer in the network serves as a gateway to KEKNET, which connects the minicomputer network and the central computers. The communication with the central computers is managed within the framework of the KEK NODAL system. NODAL programs communicate with the central computers calling NODAL functions; functions for exchanging data between a data set on the central computers and a NODAL variable, submitting a batch job to the central computers, checking the status of the submitted job, etc. are prepared.