Long-pulse beam acceleration of MeV-class H(-) ion beams for ITER NB accelerator.

In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m(2) during 3600 s D(-) ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m(2), 881 keV H(-) ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m(2).

Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion application.

High power and long-pulse negative ion extractor, which is composed of the plasma grid (PG) and the extraction grid (EXG), is newly developed toward the neutral beam injector for heating and current drive of future fusion machines such as ITER, JT-60 Super Advanced and DEMO reactor. The PG is designed to enhance surface production of negative ions efficiently by applying the chamfered aperture. The efficiency of the negative ion production for the discharge power increased by a factor of 1.3 against that of the conventional PG. The EXG is also designed with the thermal analysis to upgrade the cooling capability for the long pulse operation of >1000 s required in ITER. Though the magnetic field for electron suppression is reduced to 0.75 of that in the conventional EXG due to this upgrade, it was experimentally confirmed that the extracted electron current can be suppressed to the allowable level for the long pulse operation. These results show that newly developed extractor has the high potential for the long pulse extraction of the negative ions.

Effect of non-uniform electron energy distribution function on plasma production in large arc driven negative ion source.

Spatially non-uniform electron energy distribution function (EEDF) in an arc driven negative ion source (JAEA 10A negative ion source: 10 A NIS) is calculated numerically by a three-dimensional Monte Carlo kinetic model for electrons to understand spatial distribution of plasma production (such as atomic and ionic hydrogen (H(0)∕H(+)) production) in source chamber. The local EEDFs were directly calculated from electron orbits including electromagnetic effects and elastic∕inelastic collision forces. From the EEDF, spatial distributions of H(0)∕H(+) production rate were obtained. The results suggest that spatial non-uniformity of H(0)∕H(+) productions is enhanced by high energy component of EEDF.

First neutral beam injection experiments on KSTAR tokamak.

The first neutral beam (NB) injection system of the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak was partially completed in 2010 with only 1∕3 of its full design capability, and NB heating experiments were carried out during the 2010 KSTAR operation campaign. The ion source is composed of a JAEA bucket plasma generator and a KAERI large multi-aperture accelerator assembly, which is designed to deliver a 1.5 MW, NB power of deuterium at 95 keV. Before the beam injection experiments, discharge, and beam extraction characteristics of the ion source were investigated. The ion source has good beam optics in a broad range of beam perveance. The optimum perveance is 1.1-1.3 µP, and the minimum beam divergence angle measured by the Doppler shift spectroscopy is 0.8°. The ion species ratio is D(+):D(2)(+):D(3)(+) = 75:20:5 at beam current density of 85 mA/cm(2). The arc efficiency is more than 1.0 A∕kW. In the 2010 KSTAR campaign, a deuterium NB power of 0.7-1.5 MW was successfully injected into the KSTAR plasma with a beam energy of 70-90 keV. L-H transitions were observed within a wide range of beam powers relative to a threshold value. The edge pedestal formation in the T(i) and T(e) profiles was verified through CES and electron cyclotron emission diagnostics. In every deuterium NB injection, a burst of D-D neutrons was recorded, and increases in the ion temperature and plasma stored energy were found.

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).

Development of a plasma generator for a long pulse ion source for neutral beam injectors.

A plasma generator for a long pulse H(+)/D(+) ion source has been developed. The plasma generator was designed to produce 65 A H(+)/D(+) beams at an energy of 120 keV from an ion extraction area of 12 cm in width and 45 cm in length. Configuration of the plasma generator is a multi-cusp bucket type with SmCo permanent magnets. Dimension of a plasma chamber is 25 cm in width, 59 cm in length, and 32.5 cm in depth. The plasma generator was designed and fabricated at Japan Atomic Energy Agency. Source plasma generation and beam extraction tests for hydrogen coupling with an accelerator of the KSTAR ion source have been performed at the KSTAR neutral beam test stand under the agreement of Japan-Korea collaborative experiment. Spatial uniformity of the source plasma at the extraction region was measured using Langmuir probes and ±7% of the deviation from an averaged ion saturation current density was obtained. A long pulse test of the plasma generation up to 200 s with an arc discharge power of 70 kW has been successfully demonstrated. The arc discharge power satisfies the requirement of the beam production for the KSTAR NBI. A 70 keV, 41 A, 5 s hydrogen ion beam has been extracted with a high arc efficiency of 0.9 -1.1 A/kW at a beam extraction experiment. A deuteron yield of 77% was measured even at a low beam current density of 73 mA/cm(2).

Long pulse H- ion beam acceleration in MeV accelerator.

A multiaperture multigrid accelerator called "MeV accelerator" has been developed for neutral beam injection system of international thermonuclear experimental reactor. In the present work, long pulse H(-) ion beam acceleration was performed by the MeV accelerator equipped with new water-cooled grids. At present, the pulse length was extended to 5 s for the beams of 750 keV, 221 mA, and 10 s for the beams of 600 keV, 158 mA. Energy density, defined as products of beam energy (keV), current (mA), and pulse (s) divided by aperture area (m(2)), increased more than one order of magnitude higher compared with original MeV accelerator without water cooling in its grids. At higher energy and current, the grid was melted by beam deflection. Due to this grid melting, breakdowns occurred between the grids, and hence, the pulse length was limited. Beam deflection will be compensated by aperture displacement in next experiment.

Analysis of secondary particle behavior in multiaperture, multigrid accelerator for the ITER neutral beam injector.

Heat load on acceleration grids by secondary particles such as electrons, neutrals, and positive ions, is a key issue for long pulse acceleration of negative ion beams. Complicated behaviors of the secondary particles in multiaperture, multigrid (MAMuG) accelerator have been analyzed using electrostatic accelerator Monte Carlo code. The analytical result is compared to experimental one obtained in a long pulse operation of a MeV accelerator, of which second acceleration grid (A2G) was removed for simplification of structure. The analytical results show that relatively high heat load on the third acceleration grid (A3G) since stripped electrons were deposited mainly on A3G. This heat load on the A3G can be suppressed by installing the A2G. Thus, capability of MAMuG accelerator is demonstrated for suppression of heat load due to secondary particles by the intermediate grids.

Analyses of high power negative ion accelerators for ITER neutral beam injector (invited).

In JAEA, research and developments to realize high power accelerator (1 MeV, 40 AD(-) ion beams for 3600 s) for ITER have been carried out experimentally and numerically utilizing a five stage MAMuG (Multiaperture, Multigrid) accelerator. In this paper, the extension of the gap length, which is required to improve the voltage holding capability, is examined in two dimensional beam optics analyses and also from view point of stripping loss of ions. In order to suppress excess power loadings due to the direct interception of negative ions, which is issued in long pulse tests, the beamlet deflection is analyzed in three dimensional multibeamlet analyses. The necessary modifications shown above are applied to the MAMuG accelerator for coming long pulse tests in JAEA and ITER.

Acceleration of ampere class H(-) ion beam by MeV accelerator.

The H(-) ion accelerator R&D to realize the international thermonuclear experimental reactor neutral beam is ongoing at Japan Atomic Energy Agency (JAEA). The required performance for the prototype MeV accelerator developed at JAEA is 1 MeV, 500 mA (current density of 200 A/m(2)) H(-) ion beam at the beamlet divergence angle of less than 7 mrad. Up to 2005, 836 keV, 146 A/m(2) H(-) ion beam was successfully accelerated as the highest record of the current density at MeV class energy beams. In the present work, high current negative ion beam acceleration test was performed by increasing the beam extraction apertures from 3 x 3 (9 apertures) to 3 x 5 (15 apertures). By fixing the air leak at the source chamber due to backstream ions as well as the improvement of voltage holding capability by a new fiber reinforced plastic insulator ring, the performance of the MeV accelerator was improved. So far, H(-) ion beam of 320 mA was successfully accelerated up to 796 keV with the beam divergence angle of 5.5 mrad. The accelerated drain current including the electron reaches close to the power supply limit for the MeV test facility. The heat flux by the backstream ion during the above beam acceleration was estimated to be 360 W/cm(2). The Cs leakage to the accelerator during the test campaign (Cs total input of 5.0 g) was 0.26 mg (7.0 microg/cm(2)). This is considered to be the allowable level from the viewpoint of voltage holding.

[Bacteriostatic activity of bovine colostrum].

Succeeding the previous report on antivirus activity of non immunized bovine colostrum immunoglobulin, we studied the bacteriostatic activity of the immunoglobulin, lactoferrin and lactoferrin Fe by using the automated antimicrobial susceptibility testing system. We have presented the representative positive and negative reactions. Then, we have reported that the immunoglobulin was effective in 10 of a total of 20 species which we examined. In some species, the lactoferrin was slightly more effective than the immunoglobulin was. These results indicated that the immunoglobulin, lactoferrin and lactoferrin Fe were useful for the bacteriostatic reaction.

Human immunodeficiency virus infection in cells of myeloid-monocytic lineage.

We established persistent infection with a strain of human immunodeficiency virus type 1, HTLV-IIIB, in a promyelomonocytic cell line, ML-1 (CD4 antigen nearly negative and CD4 mRNA negative), and a promonocytic cell line, THP-1 (CD4 antigen positive). Different reaction of giant cell formation was found after co-cultivation of infected and uninfected cells of ML-1, HL-60, THP-1 and U-937 cell lines with uninfected and infected MOLT4 (a T-lymphoma cell line).

Incidence of antibodies against human immunodeficiency virus, human T-cell lymphotropic virus type 1, hepatitis B virus, hemorrhagic fever with renal syndrome virus and Chlamydia in Tonga and western Samoa.

Among the populations of Tonga and Western Samoa, serum antibodies against human immunodeficiency virus or hemorrhagic fever with renal syndrome virus were not detected (0/904 and 0/192). No serum samples were considered to be positive for antibody against human T-cell lymphotropic virus type 1 (0/527). Hepatitis B antigen and antibody were found in 4% (8/192) and 47% (90/192), respectively. Chlamydia trachomatis IgG and C. psittaci IgG antibodies were detected in 39% (75/192) and 47% (91/192), respectively. The possibilities of the spread of human immunodeficiency virus and hemorrhagic fever with renal syndrome virus on the islands when the viruses invade from abroad were discussed.

[Immunoglobulin components and anti-viral activities in bovine colostrum].

Bovine colostrum whey and immunoglobulins were prepared. Their characteristics and anti-viral activities were studied:IgG, IgA and IgM were found in bovine colostrum. Most IgG was polymerized. Although neutralization activities against bovine, simian and human rotaviruses existed, anti-human adenovirus antibody was not found. Effects on prophylaxis and treatment for rotavirus gastroenteritis were expected.

[Epidemiology of rotavirus infection around Tokyo area].

Epidemiology of rotavirus infection was studied from 1981 to 1988 mainly in three hospitals around Tokyo area. Major serotypes of rotaviruses in the three places were different from those in two hospitals around Kansai area in Japan (Ref. 6, 13), while, major serotypes were same among three hospitals. Both of serotypes 1 and 4 in group A were mostly found around Tokyo area. Frequencies of type 2, 3, and 9 in group A were low, although the frequencies were various among periods. Detail examinations of rotavirus RNA electropherotypes showed the results as follows; different electropherotypes were found during one winter season and at one hospital, the identical electropherotype was found cross a year and cross a hospital. We could not find the identical electropherotype which belong to two serotypes so far. Seven group C rotaviruses were found since 1987 in three hospitals. It would be important to examine RNA electropherotypes and serotypes for long period not only for epidemiological studies but also for development of vaccine.

Sclerosing hemangioma of the lung. An epithelial tumor composed of immunohistochemically heterogenous cells.

Lung tissues from 16 patients with pulmonary sclerosing hemangioma were studied with the use of serial sections and immunoperoxidase staining for surfactant apoprotein, secretory component (SC), and epithelial membrane antigen (EMA). The cells lining papillary projections or cystic spaces were stained with surfactant apoprotein, SC, and EMA. Characteristic round stromal cells, which were considered to be the main component of the sclerosing hemangioma, consisted of immunohistochemically heterogenous cells, that is, positive findings were attained with all three antigens, surfactant apoprotein- and EMA-positive ones, SC- and EMA-positive ones, only EMA-positive ones, and all three negative. When investigating the immunoreactivity of neoplastic type II pneumocytes in bronchioalveolar cell carcinoma and hyperplastic ones in nonneoplastic pulmonary disorders, the authors found that almost all the neoplastic type II pneumocytes had all three antigens. Many of the hyperplastic and normal type II pneumocytes, however, were stained with surfactant apoprotein and EMA but not with SC. The authors' findings add further support for the proposal that sclerosing hemangioma of the lung is epithelial in origin. In view of the various staining patterns found in the stromal cells, sclerosing hemangioma probably consists of immunohistochemically heterogenous epithelial cells. The staining pattern of the cells lining papillary projections or cystic spaces was similar to that of neoplastic type II pneumocytes rather than that of hyperplastic type II pneumocytes.

Sclerosing hemangioma of the lung. Immunohistochemical characterization of its origin as related to surfactant apoprotein.

Lung tissues from 13 patients with pulmonary sclerosing hemangioma were studied with antibody against surfactant apoprotein, Factor VIII-related antigen, or lysozyme. Surfactant apoprotein was detected in the cytoplasm of the cells lining cystic spaces and papillary projections. Surfactant apoprotein was found in a small number of stromal cells with abundant eosinophilic or clear cytoplasm and round to oval nuclei, which were characteristic in pulmonary sclerosing hemangioma as the main component. Surfactant apoprotein was also found in the stromal cells with small, dark nuclei similar to the lining cells. The lining and stromal cells contained neither Factor VIII-related antigen nor lysozyme. Our demonstration of surfactant apoprotein in these cells provides further support for the idea that pulmonary sclerosing hemangioma primarily consists of epithelial cells with differentiation to type II pneumocytes, as was deduced from ultrastructural investigations.

Immunohistological analysis of surfactant-apoprotein in the bronchiolo-alveolar carcinoma.

Fifty-five cases of bronchiolo-alveolar carcinoma were examined immunohistochemically using mono-specific antisurfactant apoprotein IgG obtained from a rabbit immunized with monkey surfactant preparations. Formalin-fixed and paraffin-embedded lung tissues were stained by an immunoperoxidase method. Antibody stained the normal and hyperplastic alveolar type II pneumocytes, but did not stain bronchial epithelium or other lung cells. In tumor tissue, 26 (47.3%) of 55 cases were positively stained in the cytoplasm, and 15 showed reaction products in both the cytoplasm and intranuclear regions. By electron microscopy osmiophilic lamellar bodies and microvilli on the free surface, thought to be characteristic of type II pneumocytes, were seen in tumor cells (2 cases). In the five cases, the nuclei contained branching tubular inclusions. The results of this study support the idea that certain bronchiolo-alveolar carcinomas originate from type II pneumocytes, the intranuclear inclusions may represent an abnormal proliferation of nuclear membranes containing surfactant-apoprotein.

Disseminated intravascular coagulation in newborn infants. Prevalence in autopsies and significance as a cause of death.

Two hundred and one consecutive autopsies of the newborns were clinicopathologically analyzed for the prevalence of disseminated intravascular coagulation (DIC) and its significance as a cause of death. DIC confirmed histopathologically by the presence of many microthrombi in three or more organs was accompanied in 24 cases (11.9%) with various underlying diseases. Factors predisposing to DIC in the newborns included hyaline membrane disease (29.2%), maternal complications (70.8%) and infections (16.7%). Microthrombi were found in the lungs of all the cases with DIC, but were rare in the kidneys, especially in glomeruli. Visceral lesions of DIC were characterized by a wide diversity of histopathological features including ischemic lesions.