Status Report of LNS Accelerator Complex in 2002(IV. Status Report of LNS Accelerator Complex in 2002)

Operation status of an electron accelerator complex at Laboratory of Nuclear Science, Tohoku University is reported. After a completion of a new building containing an experimental vault, the inspection for the radiation safety was done in the beginning of October, 2003, so that most of user machine time was consumed in the latter half of the fiscal year 2002

Status Report of LNS Accelerator Complex in 2001(IV. Status Report of LNS Accelerator Complex in 2001)

The electron accelerator complex at the Laboratory of Nuclear Science, Tohoku University has been operated for various fields of science. A 35-year-old 300 MeV electron linac is still working well. However troubles due to aging is rapidly getting serious. In addition, because of multi-purpose use of the linac many different beam characteristics are requested by the users, so that the operation mode has been complicate. In this report, the operation status of the accelerator complex including major troubles experienced in the fiscal year 2001 is described and future plan is shortly discussed by showing the present machine operation

Extraction of a strongly focusing He + beam from three-stage concave electrodes for alpha particle measurement system in ITER

A strongly focusing He + ion beam source equipped with concave multi-aperture electrodes was developed for production of He - through a charge exchange cell. The beam was extracted at a voltage less than 20 kV from 301 apertures distributed in an area of 100 mm , and focused at 750 mm distance. The beam current and the beam size of 2 A and 20 mm in diameter, respectively, were achieved with an arc power less than 10 kW. The optimum perveance was obtained at 0.02 AkV 1.5 at the beam energy less than 20 keV which is suitable for the conversion to He - in an alkali vapor cell

Characterization of scintillators for lost alpha diagnostics on burning plasma experiments

The characteristics of light output by ion beam irradiations under high ion fluxes have been measured for three kinds of scintillators: ZnS:Ag deposited on the glass plate, Y_3Al_5O_12:Ce powder stiffened with a binder, and Y_3Al_5O_12:Ce ceramics sintered at high temperature. The ion beam flux in the range from 10^12 to 10^13 ions/(cm^2 s) is irradiated to simulate the burning plasma experiments. The decrease of light output has been observed by long time ion irradiation. The deterioration of ZnS:Ag deposited scintillator is most serious. The deterioration has been improved for the scintillators of Y_3Al_5O_12:Ce with a binder and that sintered. Their applications to ITER lost alpha diagnostics are discussed

18F-FDG PET/CT Evaluation of Regional Cerebral Metabolic Activities in Childhood Onset Schizophrenia

Introduction: Functional neuro-imaging with FDG PET CT in schizophrenic patients have reported certain patterns of increased or decreased metabolism in specific areas of the brain. Frontal lobe is one of the cortical areas consistently associated with schizophrenia and the activity levels have been reported to vary with the symptomatology at presentation. Predominantly positive symptoms cause and underlying hyperfrontality and negative symptoms are associated with hypofrontality. This study aims to assess the imaging patterns in unmedicated pediatric patients with a diagnosis of schizophrenia and predominantly positive symptoms.Patients and methods: 48 pediatric patients with a diagnosis of schizophrenia (all unmedicated, 38 never medicated) and 10 healthy age-matched controls were evaluated with FDG PET CT. The patients met ICD-10 and DSM-IV criteria for schizophrenia and all reported psychotic, “positive†symptoms when tested.Results: Children with schizophrenia and positive symptoms had a pattern of diffuse hyper-metabolism involving the bilateral frontal cortices and could be demonstrated on quantification by region to occipital ratio comparison . Associated statistically significant differences were also found when comparing ratios of occipital to thalamic, striatal and temporal cortex in these patients when compared to controls.Conclusion: Diffuse frontal hypermetabolism or hyperfrontality is observed in children with schizophrenia when there is a predominance of positive symptoms. There could be a possible disruption of cortico-striato-thalamic feedback loops causing hyperfrontality as seen in in experimentally induced models of psychosis