Bench Testing of New Polarimeter with Silicon Photoelastic Modulator for Short Wavelength FIR Laser

A short wavelength laser whose wavelength is about 50 μm is preferable for a polarimeter and an interferometer in large fusion devises. This paper reports the development of a polarimeter with a photoelastic modulator(PEM) for a CH3OD laser (wavelengths of 57.2 and 47.6 μm). The PEM with a high-resistive silicon as a photoelastic element has been newly developed. The transmissivity of the high-resistive silicon is high in a far infrared region. The polarimeter with the Si PEM has been tested and the polarization angle is successfully measured. Noise sources (a multi-reflection of the laser beam in the photoelastic element, a measurement error of amplitude of a detector output and an estimation error of the retardation) of the measured angle are also discussed

Advanced Laser Diagnostics for Electron Density Measurements

This paper describes innovative laser diagnostics under development at the National Institute for Fusion Science, aiming for the establishment of reliable density measurement techniques in the next step magneticallyconfined fusion devices. There are two approaches, interferometry and polarimetry. A new type of two color laser (47.6/57.2-μm CH3OD) interferometer has been developed and its original function, vibration subtraction,was confirmed in a test stand. The line integrated density measurement at Compact Helical System by using the polarimeter based on Cotton-Mouton effect was demonstrated by the use of a 337-μm HCN laser source

Improvements of CO2 Laser Heterodyne Imaging Interferometer for Electron Density Profile Measurements on LHD

After installation of CO2 laser (wavelength 10.6 μm) heterodyne imaging interferometer (CO2 HI) in 2001, continuous developments have been carried out to improve the measurements capability and stability of operation. The CO2 HI works almost without phase jumping at high electron density (> 1 × 1020 m-3), where the existing far infrared laser (wavelength 118.9 μm) interferometer suffers from fringe jump due to the reduction of signal intensity caused by refraction. However a second interferometer is required to compensate mechanical vibration. A YAG laser (wavelength 1.06 μm) heterodyne imaging interferometer (YAG HI) is presently used for the vibration compensation. In the 10th LHD experimental campaign (2006?2007), sixty four channels of CO2 HI to measure electron density profile and ten channels of YAG HI to measure mechanical vibration are working. A measurement example of a pellet fuelled high-density discharge is reported

Conceptual Design of Electron Density Measurement System for DEMO-Relevant Helical Plasmas

Electron density measurement remains indispensable to control fueling on a DEMO reactor. For steady-state operation of the DEMO reactor, density measurement should be highly reliable and accurate. A dispersion interferometer and a Faraday polarimeter are free from measurement errors caused by mechanical vibrations. Hence combination of the two diagnostics yields a suitable system for density measurement on future steady-state fusion reactors. A wavelength around 1 ?m is one of the desirable candidates in terms of the fringe shift and the Faraday rotation angle, the variety of optical components, and the efficiency of frequency doubling for the dispersion interferometer. This paper presents a conceptual design for the dispersion interferometer and Faraday polarimeter with a 1 ?m light source

CD146 is a potential immunotarget for neuroblastoma

Neuroblastoma, the most common extracranial solid tumor of childhood, is thought to arise from neural crest-derived immature cells. The prognosis of patients with high-risk or recurrent/refractory neuroblastoma remains quite poor despite intensive multimodality therapy; therefore, novel therapeutic interventions are required. We examined the expression of a cell adhesion molecule CD146 (melanoma cell adhesion molecule [MCAM]) by neuroblastoma cell lines and in clinical samples and investigated the anti-tumor effects of CD146-targeting treatment for neuroblastoma cells both in vitro and in vivo. CD146 is expressed by 4 cell lines and by most of primary tumors at any stage. Short hairpin RNA-mediated knockdown of CD146, or treatment with an anti-CD146 polyclonal antibody, effectively inhibited growth of neuroblastoma cells both in vitro and in vivo, principally due to increased apoptosis via the focal adhesion kinase and/or nuclear factor-kappa B signaling pathway. Furthermore, the anti-CD146 polyclonal antibody markedly inhibited tumor growth in immunodeficient mice inoculated with primary neuroblastoma cells. In conclusion, CD146 represents a promising therapeutic target for neuroblastoma

Conceptual Design of a Dispersion Interferometer Using a Ratio of Modulation Amplitudes

Since a dispersion interferometer is free from mechanical vibrations, it does not need a vibration compensation system even for a probe beam with a short wavelength. This paper describes a new signal processing of the dispersion interferometer using a ratio of modulation amplitudes with a photoelastic modulator. The proposed method is immune to changes in detected signal intensities, thus making the signal processing system simple. Designs of the optical system of the dispersion interferometer for proof of principle, especially specification of a nonlinear optical crystal, are also shown

Improved Resolution and Stability in a Dispersion Interferometer Using a Modulation Amplitude Ratio

A dispersion interferometer is immune to mechanical vibrations, which is a great advantage for application to steady-state fusion reactors. This paper describes the performance of a phase-modulated dispersion interferometer with a new phase extraction method using a modulation amplitude ratio