Coherent Cherenkov radiation as an intense THz source

Diffraction and Cherenkov radiation of relativistic electrons from a dielectric target has been proposed as mechanism for production of intense terahertz (THz) radiation. The use of an extremely short high-energy electron beam of a 4th generation light source (X-ray free electron laser) appears to be very promising. A moderate power from the electron beam can be extracted and converted into THz radiation with nearly zero absorption losses. The initial experiment on THz observation will be performed at CLARA/VELA FEL test facility in the UK to demonstrate the principle to a wider community and to develop the radiator prototype. In this paper, we present our theoretical predictions (based on the approach of polarization currents), which provides the basis for interpreting the future experimental measurements. We will also present our hardware design and discuss a plan of the future experiment

Impact of liquid metal surface on plasma-surface interaction in experiments with lithium and tin capillary porous systems

The lithium and tin capillary-porous systems (CPSs) were tested with steady-state plasma in the PLM plasma device which is the divertor simulator with plasma parameters relevant to divertor and SOL plasma of tokamaks. The CPS consists of tin/lithium tile fixed between two molybdenum meshs constructed in the module faced to plasma. Steady-state plasma load of 0.1 - 1 MW/m(2) on the CPS during more than 200 min was achieved in experiments on PLM which is a modeling far scrapeoff- layer and far zone of divertor plasma of a large tokamak. The heating of the CPS was controlled remotely including biasing technique which allows to regulate evaporated metal influx to plasma. After exposure, the materials of the tin and lithium CPSs were inspected and analyzed with optic and scanning electron micriscopy. Experiments have demonstrated sustainability of the tin and lithium CPSs to the high heat steady state plasma load expected in a large scale tokamak. The effect of evaporated lithium and tin on the plasma transport/radiation was studied with spectroscopy to evaluate changes of plasma properties and plasma-surface interaction

『新撰万葉集』の風物表現に関する和漢比較研究——上巻の和歌と漢詩を中心に

《新撰万叶集》成立于“国风暗黑时代”向“和风复兴时代”转变的过程中，在日本古典文学史上占有极其重要的地位。该集由上下两卷组成，其中上卷的每一首和歌的左边都附有一首七言绝句，可以说包含着编撰者特殊的编撰意图。该集这种“和汉共存”的特点不断吸引着和汉比较文学学界的关注。 至今为止的研究主要是从“和汉共存”出发，围绕该集的和歌和汉诗的表达、抑或是和歌和汉诗的关系论而展开的。为了更加客观地把握该集在日本古典文学史上的地位，我们要对“和汉共存”这一点开展进一步的研究。本论文把该集的汉诗作者看成该集和歌的鉴赏者之一。并由此出发，摒弃一直以来对本集的汉诗所持的偏见，把《新撰万叶集》上卷的和歌和其相应的汉诗...「国風暗黒時代」から「和風復興時代」へと進行していった過程に成立された『新撰万葉集』（以下は「本集」とも）は、日本古典文学史上で極めて重要な地位を占めている。本集は上下二巻からなるが、上巻は和歌とともにその左に七言絶句が付されているもので、特別な編纂意図が含まれるに違いない。その「和漢共存」という点で和漢比較文学学界の注目を引き続く。 今日まで、「和漢共存」から主に本集における和漢詩歌の表現や和歌と漢詩との関係論をめぐって行われてきたが、本集の日本古典文学史における地位をより客観的に把握するために、更なる研究が期待される。本論は、本集の漢詩作者は本集の和歌の鑑賞者でもあることから出発し、従来の本集の漢詩に対する偏見に挑み、『新撰万葉集』上巻の和歌とそれに付される漢詩を、平安人の作詩を中心とする文学上の訓練とその成果の総決算の縮図の一つと見なす。その認識の上で、先学の研究成果を踏まえながら...学位：文学硕士院系专业：外文学院日本语言文学系_日语语言文学学号：1222007115181

Effect of SiO2_{2} passivating layer in segmented silicon planar detectors on the detector response

Silicon detectors with a fine segmentation (micropixel and microstrip) are the main type of detectors used in the inner trackers of LHC experiments. Due to the high luminosity of the LHC machines they are required to have a fast response to fit the short shaping time of 25 ns and to be radiation hard. Evaluation of silicon microstrip detectors developed for the ATLAS silicon tracker and carried out under collaboration of CERN and PTI has shown the reversal of the pulse polarity in the detector response to short- range radiation. Since the negative signal is of about 30% of the normal positive one, the effect strongly reduces the charge collection efficiency in irradiated detectors. The investigation presents the consideration on the origin of a negative response in Si microstrip detectors and the experimental proof of the model. The study of the effect has been carried out using "baby" strip detectors with a special design: each strip has a window in a metallization, which covers the p/sup +/ implant. The scan of the laser across the strips clearly shows that the negative response is observed along the scan in the inter-strip gap. As soon as the light spot is placed on the strip p/sup +/ implant the negative response disappears and the value of the charge collected by the active strip proportionally increases. A phenomenological model considers the origin of the negative response as the effect of carrier trapping at the Si/SiO/sub 2/ interface between the strips

Current injected detectors (CID): a new approach for detector operation in very high radiation environment

For the upcoming Super LHC (SLHC) experiments on the LHC upgrade, Si detectors will still be considered as the main detectors for inner tracker. However, the radiation level in SLHC will be up to 10 times more than that in LHC due to the increase of luminosity from 10/sup 34based on the current injection in the detector bulk is considered. It is shown that the symmetric p/sup positive n-p/sup positive structures as well as regular p/sup positive n-n/sup positive silicon detectors after irradiation by neutrons up to 5centerdot10/sup 14/ cm /sup -2/ can operate at self-stabilized current injection (SSCI) or space charge limited current (SCLC) mode. This provides a stable electric field profile at any higher fluences with the electric field distributed in the entire detector thickness (full depletion mode). In this study operation of heavily irradiated Si detectors in the SSCI mode is confirmed by the measurements of I-V characteristics, which show the region with square I on V dependence and then the sharp current rise at a threshold voltage. It is shown that the threshold voltage rises linearly with the irradiation fluence that allows biasing the detectors by higher voltage with the fluence increase. This is obviously helpful for reduction of the collection time and consequently the related charge loss due to trapping