Cancer of Unknown Primary Site:A Review of 28 Cases and the Efficacy of Cisplatin/Docetaxel Therapy at a Single Institute in Japan

We evaluated the efficacy and toxicity of cisplatin/docetaxel (CDDP/TXT) chemotherapy and identified prognostic factors in Japanese patients with cancer of unknown primary site (CUP). Twenty-eight consecutive patients seen at a single institute were reviewed retrospectively. Sixteen patients were treated with TXT 80mg/m2, followed by CDDP 75mg/m2. The overall response rate to CDDP/TXT treatment was 62.5%, with a median survival time (MST) of 22.7 months. Common adverse reactions were myelosuppression and hyponatremia. The MST of all 28 patients with CUP was 8.3 months, and the 1-year overall survival rate was 45.6%. Univariate analysis identified 5 prognostic factors:performance status, liver involvement, bone involvement, pleural involvement, and lymph node involvement. In conclusion, CDDP/TXT chemotherapy is effective with tolerable toxicity in patients with CUP. Japanese patients with CUP might be chemosensitive and may survive longer

X-ray harmonic comb from relativistic electron spikes

X-ray devices are far superior to optical ones for providing nanometre spatial and attosecond temporal resolutions. Such resolution is indispensable in biology, medicine, physics, material sciences, and their applications. A bright ultrafast coherent X-ray source is highly desirable, for example, for the diffractive imaging of individual large molecules, viruses, or cells. Here we demonstrate experimentally a new compact X-ray source involving high-order harmonics produced by a relativistic-irradiance femtosecond laser in a gas target. In our first implementation using a 9 Terawatt laser, coherent soft X-rays are emitted with a comb-like spectrum reaching the 'water window' range. The generation mechanism is robust being based on phenomena inherent in relativistic laser plasmas: self-focusing, nonlinear wave generation accompanied by electron density singularities, and collective radiation by a compact electric charge. The formation of singularities (electron density spikes) is described by the elegant mathematical catastrophe theory, which explains sudden changes in various complex systems, from physics to social sciences. The new X-ray source has advantageous scalings, as the maximum harmonic order is proportional to the cube of the laser amplitude enhanced by relativistic self-focusing in plasma. This allows straightforward extension of the coherent X-ray generation to the keV and tens of keV spectral regions. The implemented X-ray source is remarkably easily accessible: the requirements for the laser can be met in a university-scale laboratory, the gas jet is a replenishable debris-free target, and the harmonics emanate directly from the gas jet without additional devices. Our results open the way to a compact coherent ultrashort brilliant X-ray source with single shot and high-repetition rate capabilities, suitable for numerous applications and diagnostics in many research fields

Analytical solution for phase space evolution of electrons operating in a self-amplified spontaneous emission free electron laser

I present an analytical solution for the phase space evolution of electrons in a self-amplified spontaneous emission (SASE) free-electron laser (FEL) operating in the linear regime before saturation in the resonant case by solving the one dimensional FEL equation together with the solution of the cubic equation, which represents the evolution of the SASE FEL field. The electrons are shown to be bunched around π/6 ahead of a resonant electron every resonant FEL wavelength in the high gain regime. The phase relation is similar to that in a low gain FEL where an electron beam above resonance is injected, explaining the positive FEL gain. The analytical solutions agree well with numerical simulations and are applied to obtain the coherent optical transition radiation (OTR) intensity produced from electron microbunching at FEL wavelength. The coherent OTR intensity is shown to be proportional to FEL intensity

A New Compact 3GeV Light Source in Japan

最先端蓄積リング設計MBAラティスを用いた周長350mの3GeV次世代放射光加速器を東日本に建設している。安定性と高性能を兼ね備えたエミッタンス1nmrad運転を目指し、様々な設計と開発を進めてきた。機能複合偏向電磁石を用いた4BAラティス、高次モード(HOM)吸収体を内部に備えたビーム進行方向にコンパクトなTM020モード空胴、小さな入射ビーム振幅と入射時の蓄積ビーム振動の極小化を目指す真空封止無摂動off-axis入射スキーム、将来の軟X線自由電子レーザーへの拡張性も兼ね備えた線型加速器及び電子源などが開発項目である。加速器機器の建屋への設置も順調に進めている。本発表では、3GeV放射光加速器の開発結果と機器設置状況の現状に関し報告する。13th International Particle Accelerator Conferenc

Development of a multialkali photocathode dc gun for a Smith-Purcell terahertz free-electron laser

We have developed a photocathode dc gun for a compact Smith-Purcell free-electron laser in the terahertz wavelength region. The gun system consists of an alkali antimonide photocathode preparation chamber, a dc gun with a 250 kV-50 mA Cockcroft-Walton high-voltage power supply, and a downstream beamline with a water-cooled beam dump to accommodate a beam power of 5 kW. We fabricated a Cs3Sb photocathode with quantum efficiency of 5.8% at a wavelength of 532 nm and generated a 150 keV beam with current of up to 4.3 mA with a 500 mW laser. A vacuum chamber for the Smith-Purcell free-electron laser has been installed in the downstream beamline. We describe the present status of our work

Development of a multialkali photocathode dc gun for a Smith-Purcell terahertz free-electron laser

We have developed a photocathode dc gun for a compact Smith-Purcell free-electron laser in the terahertz wavelength region. The gun system consists of an alkali antimonide photocathode preparation chamber, a dc gun with a 250 kV-50 mA Cockcroft-Walton high-voltage power supply, and a downstream beamline with a water-cooled beam dump to accommodate a beam power of 5 kW. We fabricated a Cs3Sb photocathode with quantum efficiency of 5.8% at a wavelength of 532 nm and generated a 150 keV beam with current of up to 4.3 mA with a 500 mW laser. A vacuum chamber for the Smith-Purcell free-electron laser has been installed in the downstream beamline. We describe the present status of our work

Operational experience of a 500 kV photoemission gun

Operational experience of a 500 kV photoemission gun at the compact energy recovery linac (cERL) of the High Energy Accelerator Research Organization is presented. The gun, developed at the Japan Atomic Energy Agency, was found to have failures in two out of the ten-segment ceramic insulator just after installation at cERL. The gun had been operated at 390 kV with eight segments until April 2015 and provided a 0.9 mA beam. An additional two-segment insulator was installed on the top of the existing insulators to recover the high-voltage performance. The gun was then conditioned up to 539 kV and has been operated stably at 500 kV. No discharge caused by the gun itself was observed at 500 kV once the high threshold voltage for stable operation exceeded 500 kV. A dark current of a few picoamperes was generated at 500 kV from a photocathode puck with a semiconducting wafer, while no dark current was observed without a semiconducting wafer. Stable generation of a 500 keV beam with current greater than 0.8 mA was demonstrated for more than two hours

Oprational experience of a 500 kV photoemission gun

Operational experience of a 500 kV photoemission gun at the compact energy recovery linac (cERL) of the High Energy Accelerator Research Organization is presented. The gun, developed at the Japan Atomic Energy Agency, was found to have failures in two out of the ten-segment ceramic insulator just after installation at cERL. The gun had been operated at 390 kV with eight segments until April 2015 and provided a 0.9 mA beam. An additional two-segment insulator was installed on the top of the existing insulators to recover the high-voltage performance. The gun was then conditioned up to 539 kV and has been operated stably at 500 kV. No discharge caused by the gun itself was observed at 500 kVonce the high threshold voltage for stable operation exceeded 500 kV. A dark current of a few picoamperes was generated at 500 kV from a photocathode puck with a semiconducting wafer, while no dark current was observed without a semiconducting wafer. Stable generation of a 500 keV beam with current greater than 0.8 mA was demonstrated for more than two hours