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Asymmetry of the motional Stark spectrum is caused by large angular divergence of an injected natural beam. To avoid this difficulty caused by the spectrum asymmetry, only the σ component is used to determine the pitch angle in the case of a high magnetic field with an optical system that contains two polarizers tilted ± 45° with respect to the horizontal direction. It is predicted that the pitch angle could be measured with an accuracy better than 0.2°.

A high-temperature radiation source has been developed for the absolute calibration of diagnostic instruments for measuring electron cyclotron emission from high-temperature plasmas. The source has a radiation area of φ 150 mm and can be heated up to 500°C. The measured emissivity of the source is close to unity in the spectral region between 200 and 500 GHz. The grating polychromator has been calibrated using the radiation source developed. The obtained temperatures agree with those by the pulse height analysis of soft X-rays and Thomson scattering measurement within 10%.

An HCN laser scattering technique is employed for detecting an electrostatic wave excited by ICRF heating on the JIPP T-IIU tokamak. The frequency spectra and wavenumber of the excited wave were observed during the heating. The measured wave is consistent with the theoretically estimated wave dispersion of the ion Bernstein wave which is mode-converted from the fast wave in the vicinity of the ion-ion hybrid resonance layer. The influence of MHD activity on the mode-converted ion Bernstein wave is examined. When the MUD activity grows and the plasma becomes unstable, the scattered signal from the ion Bernstein wave decreases, being accompanied with large fluctuations.

A new technique for local magnetic field measurement in a bumpy torus NBT‐1M (which is a magnetic plasma confinement device) has been developed using a rapid‐frequency‐scan (RAFS) laser system combined with sodium atomic beam probing. The RAFS laser beam excites the sodium D1 transition in the plasma cavity, and the Zeeman pattern is determined with laser fluorescence spectroscopy in a single laser shot. From the Zeeman splitting, the transient magnetic field distribution in the plasma, produced by electron cyclotron resonance heating (ECH), is measured with an accuracy of ±3.2%, a spatial resolution of 5 mm, and a temporal resolution of 5 μs.

The use of a toroidal magnetic field as a lens system is proposed for producing an intense ion beam. The characteristics of the lens system are obtained both analytically and numerically. Some examples of ray-trajectories are presented for different focal lengths. The system is applicable to neutral beam injection heating and micro-pellet implosion for nuclear fusion, and to other fields such as ion beam X-ray lasers.

Since the foundation of FPDC in April 1985, a system (FPDC-SRX) for the synchrotron radiation experiment at UVSOR facility of IMS, Okazaki, has been developed for the purpose of establishing calibration techniques of optical components, detectors and spectrometers for plasma diagnostics. The SRX is composed of a beam line (BL5B), a primary monochromator of plane grating type and a calibration chamber. The present status of the SRX is described, although the calibration chamber is being designed.

A six‐channel HCN laser interferometer system has been developed for the measurement of the electron density profile in the JIPP T‐IIU tokamak. The fringe shift of the probe beam is directly read out using a reference beam, the frequency of which is Doppler shifted by 50 kHz with a rotating grating. The optical configuration is of the Michelson interferometer type, of which reflecting mirrors are directly attached on the wall of the vacuum vessel. An effective area of the optical window is only φ40 mm. This optical configuration enables us to make the electron density profile measurements by the multichannel laser interferometer with a single small optical window.

A novel technique to measure the magnetic field strength is demonstrated, which is based on blow‐off beam probing combined with Doppler‐tuned laser spectroscopy. The field strength is determined from the Zeeman splitting of the LiI resonance line (670.8 nm) with good time and spatial resolutions (Δt

Spase and time resolved Mach-Zebnder interferometer is applied to study a slow theta pinch plasma. Methods of timing operations and experimental arrangements are described. The plasma is pinched in the third half cycle of discharge period. The interferogram shows that the peak electron density varies from about 1 x 1016 to 1 x 1017 cm-3 as the filling gas pressure is varied from 25 to 400 mtorr. The radial distribution of shell structure is observed when a small reverse bias field is added. The relaxation time of this field is longer at the lower gas pressure. In the pressure range of higher than 40 mtorr, a flute-type instability appears. But no drift motions are observed. Interferograms show various modes of instabilities. The loss rate of the total number of electrons is estimated and the result is in good agreement with a theoretical model of steady magnetohydrodynamic fluid.

For the measurement of a profile of spectral line, a high dispersive monochrometer with an Echelle-grating and 12 channels of photoelectric devices using thin glass sheets, to separate the line profile are constructed. The measured resolving power is about 2×105 and the linear dispersion at the image plane is 1.2 mm/A. This instrument is applied to measure the ion temperature of MACETIE device by using the line of He II 4686 A.

An apparatus dedicated to characterizing the VUV and soft x‐ray optical elements was fabricated, and a preliminary test on its performance was made in the soft x‐ray region with a grasshopper monochromator at the Photon Factory. The results demonstrated that quantitative evaluation of diffraction efficiency of a grating could be easily performed using the apparatus.

A lambda gt11-random-primed-cDNA clone specific for chronic hepatitis C was isolated from pooled serum presumably infected by hepatitis C virus. The translation product of the clone detect 50% of patients with chronic hepatitis C in 4 test panels but none of the patients with acute hepatitis C, other liver diseases or normal controls was positive for the peptide. The nucleotide sequence of the cDNA clone, the size of which is 66 bp, has no homology to the complete sequences of known human viruses such as adenovirus, coxsackievirus, rhinovirus, immunodeficiency virus type 1, Epstein-Barr virus, polioma virus, poliovirus, papilloma virus, parvovirus, papovavirus, varicella-zoster virus, yellow fever virus, endogenous retrovirus, T-cell lymphotropic virus types I, II, and III Japanese encephalitis virus, and hepatitis A, B, and D viruses. Probably only one or two epitopes are present on the molecule encoded by the clone as the peptide consists of only 22 amino acid residues.

A metal-film bolometer has been developed for reliable measurements of the radiation power from high-temperature plasmas. Its sensitivity and time response were improved by reducing the absorber thickness (10 µm) to the minimum limit in order to sufficiently absorb photons with high energies up to 3 keV. In addition, this detector has well-defined thermal characteristics. The deviation of the measured value arising from thermal cooling was investigated by numerically solving a heat conduction equation associated with the detector. The calculated results could explain the thermal characteristics well for a temporally constant power (at calibration) and showed that the deviation of the measured radiation power from its calculated value could be reduced by a precise correction (to the extent of 0.5%).

The characteristics of a Johann-type crystal spectrometer with a photodiode array (PDA) are described. The crystal used is LiF(200) with a bending radius of 100 cm, and the sensitivity of the PDA is measured for X-rays of 4 to 17 key. The collection efficiency η of charges created in the PDA is determined as a function of the X-ray energy E(keV): η=-0.026E+0.68. An asymmetrical spectral profile is observed when a monochromatic X-ray beam is incident on the PDA with an angle larger than 40°. The sensitivity of the spectrometer is also calibrated against a conventional X-ray tube. The PDA is used for the observation of X-ray lines from a high-temperature plasma in a vacuum spark. The resultant Fe Kα spectrum shows a spread over several channels due to blooming, when compared with that recorded on Kodak no-screen X-ray film.

A 10-channel grating polychromator has been developed and applied for the measurements of the second harmonic electron cyclotron emission from the JIPP T-IIU tokamak plasma. The frequency resolution measured at 150 GHz is about 3 GHz which corresponds to the spatial resolution of 1.8 cm near the center of the plasma column. The grating efficiency is about 80% for S-polarization around 160 GHz. Its excellent time resolution, Δt≤2 µs, is favorable for studying MHD activities in hot plasmas. It has been found from the measurements in JIPP T-IIU that the grating polychromator is a powerful diagnostic tool for the measurements of electron temperature of the plasma.

The characteristics of a thermistor, a metal-film bolometer, and a pyroelectric detector were investigated with the aim of attaining a highly reliable bolometric measurement. The spurious signal which appears on a pyroelectric detector was sufficiently eliminated by setting a mask close to the detector, thus avoiding the direct incidence of photons at the electrode. Whether a signal was true or false could be determined from the integrated value of the signal. Calibrations were performed with a HeNe laser in consideration of reflections on the detector surface. No time drift was observed on the sensitivity determined in such a way. The radiation power measured with a pyroelectric detector agreed within 10% with that measured with a calibrated metal-film bolometer.

Successful oscillation of a tunable, high-power argon excimer laser is reported. The wavelength was tuned from 124.5 to 127.5 nm with a spectral width of 0.3 nm. The output power of 2.2 MW, obtained at the line center, is 3 orders of magnitude larger than the value reported previously by Wrobel et al. [Appl. Phys. Lett. 36, 113 (1980)]. The possibility of frequency conversion of the argon excimer laser radiation to other wavelengths by a stimulated Raman scattering process is discussed.

Fundamental characteristics of a GaAs Schottky barrier diode mixer have been measured for the purpose of using it as the detector of a twin 118.8 µm CH3OH laser interferometer. The mixer sensitivity for beat oscillations of the twin lasers was measured in a frequency region from 1 MHz to 7 MHz. A signal to noise ratio of I.F. signal over 45 dB is obtained for the frequency up to 6 MHz. The dependence of the mixer sensitivity on local beam power was also measured. The I.F. signal level is approximately proportional to the local beam power in power level from 0.1 mW to 1.2 mW.

For the measurement of the profile of a spectral line, a high dispersive monochromator with an Echelle grating and 12 channels of photoelectric devices using thin glass sheets to separate the line profile was constructed. The measured resolving power is about 2×105 and the linear dispersion at the image plane is 1.2 mm/Å at 5000Å. This instrument was used to measure the ion temperature of a BSG device by employing the 4686Å line of He II.

N-type indium antimonide shows the photoconductive effect not only in the far infrared, but also in the millimeter-wave region. Millimeter-wave photoconductivity was observed in the 2 mm-wave region to clarify the origin of the effect. It is concluded that, in elements with low carrier concentration, the impurity transition between shallow donor levels is the main process for the photoconductivity, while the hot electron photoconductive effect is small as compared with the impurity photoconductivity. Performances as a millimeter-wave detector are also studied. Signal-to-noise ratio of InSb detector is superior to that of conventional silicon point contact diode. Rise and decay times of the detector without magnetic field are about 0.4 µs and 0.7 µs respectively. This detector is useful even for measurements of incoherent radiation.