111 research outputs found

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    Detection and localization of early- and late-stage cancers using platelet RNA

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    Cancer patients benefit from early tumor detection since treatment outcomes are more favorable for less advanced cancers. Platelets are involved in cancer progression and are considered a promising biosource for cancer detection, as they alter their RNA content upon local and systemic cues. We show that tumor-educated platelet (TEP) RNA-based blood tests enable the detection of 18 cancer types. With 99% specificity in asymptomatic controls, thromboSeq correctly detected the presence of cancer in two-thirds of 1,096 blood samples from stage I–IV cancer patients and in half of 352 stage I–III tumors. Symptomatic controls, including inflammatory and cardiovascular diseases, and benign tumors had increased false-positive test results with an average specificity of 78%. Moreover, thromboSeq determined the tumor site of origin in five different tumor types correctly in over 80% of the cancer patients. These results highlight the potential properties of TEP-derived RNA panels to supplement current approaches for blood-based cancer screening

    Efficient, low threshold ion-implanted channel waveguide lasers

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    He+ Ion implantation has been used to create channel waveguides in Nd doped YAG and GGG. Low threshold, efficient, diode-pumped laser performance is reported

    Ion implanted channel wave-guide laser

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    We report what we believe to be the first laser operation of channel waveguides formed in Nd-doped crystals by high energy ion implantation. Recently, there has been much interest shown in the fabrication of waveguides by various methods in crystal laser hosts

    Ion implanted quasi-three-level Yb:YAG waveguide lasers

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    Yb:YAG has manv advantages compared to the widely used Nd:YAG system. These include closer pump and laser wavelengths, leading to a more efficient transfer of energy from the pump to laser photons and less thermal loading of the gain medium. Excited state absorption, upconversion, and concentration quenching are also reduced because of the fact that there is only one excited 4f manifold. Efficient, room-temperature operation of a bulk Yb:YAG laser at 1.03 µm has recently been reported showing that the broad absorption bands are well suited to diode pumping

    Ion-implanted crystal waveguide lasers

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    We report laser action in planar waveguides formed by ion implantation in five different neodymium-doped host crystals. The performance of these devices, including thresholds, slope efficiency and diode-pumped operation, will be described
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