A high resolution laser spectrometer using AlGaAs and InGaAsP diode lasers has been developed. Wideband frequency tuning has been obtained by sweeping the operating temperature from 210K to 370K. The laser frequency is stabilized by suppressing fluctuations of the temperature and the injection current to 1mK and 2μA, respectively.

  We have applied the spectrometer to observe several overtone and combination bands of NH₃ and C₂H₂. The obtained results showed its good performance in high resolution spectroscopy of molecules. The obtained sensitivity is about 10^-9cm^-1.

  Radiophotoluminescent (RPL) glass dosimetry system has been improved with high progress by using nitrogen gas laser as UV excitation source. This new read-out system provides the discrimination of predose during read-out, no more necessity of glass cleaning before read-out and the automatic repetitive read-outs within a short time. It is possible to measure low dose to 0.03mSv with high accuracy. Now, RPL glass dosimetry system is applicable to individual and environmental monitoring.

  This paper reviews the recent progress in RPL glass dosimetry with respect to read-out systems using nitrogen gas laser.

  New neutron detection methods using the ³He-Ne lasing are explained. These methods are mainly based on two types of lasing : Nuclear Pumped Laser (NPL) and Radiation Triggered Laser (RTL). In the NPL mode, the charged particles produced by neutron reactions dirctly excite the laser gas, and then the lasing occurs. The direct NPL output power and the optical gain are available as signals to measure the thermal neutron flux. In the RTL mode, the neutron irradiation raises the discharge of the laser gas when a specific voltage is applied, and then the lasing occurs. This method is based on the variation of the lasing voltage by the neutron irradiation.

  For the detection of isotopes of ultra low abundance, the time of flight mass spectrometer system is under development by using the technique of resonance inoization spectroscopy (RIS) to selectively ionize a neutral atom of interest. We will describe preliminary study of xenon and barium isotopes in order to detect single atom of the selected Z and A.

  The Joint Work Session of the ITER CDA (Conceptual Design Activities) by four parties, (eg. Japan, USA, USSR and EC), which has continued during 3 years from May 1988 to December 1990 was completed successfully. During the CDA, overall diagnostic systems for the next generation machine was performed for the first time and the principal tasks of Diagnostic research and development (R&D) are identified. In this paper, radiation hardening problems, which should be solved for the period 1991 through 1996 of the ITER EDA (Engineering Design Activities), are described.

  Radiation damege effects on particle detectors of high intensity hadron collider experiments become a major concern for physicists who design the experiments. Radiation dose expected amounts to 6×10³ Gy per year for the silicon detectors placed around the interaction point. Albedo neutron flux from the calorimeter is expected to be 10¹²～10¹³ neutrons per year. Since a safety detector operation for ten years is required, some detector elements including read out electronics should be rad-hard and they must survive with ≦ 10⁵ Gy dose. Radiation effects on the silicon tracking device which will be installed in the SDC detector of SSC experiment are discussed.

  Commercially available sensors and related components for fusion diagnostics were irradiated with 14-MeV neutrons from OKTAVIAN or RTNS-II. Spectral response of the sensors to 14-MeV neutrons was measured, and experimental formulas for fusion neutron-induced backgrounds of the sensors are given by fitting their pulse height distributions with a summation of expon-ential functions. This paper also shows typical neutron irradiation effects on the related components and their hardness levels to mean 14-MeV neutron fluences at which their important performance degrades 10%. These data and formulas are useful for the estimation of lifetimes and background levels of fusion diagnostic systems which may be located in the 14-MeV neutron environment of a fusion reactor.

  Heavy ion induced phenomena in silicon surface barrier detector (SSB) are reviewed, including the formation and erosion of plasma column, plasma delay, pulse height defect, and charge collection process. For the understanding of these phenomena, electric property of a plasma column is discussed in detail. With the knowledge of the phenomena in SSB, single event phenomena are easily explained. If we can make the electron-hole density of the plasma column lower and its electric property not being conductor-like, the single event phenomena will not occur. One way to avoid the single event phenomena is to develop semiconductor material with lower density.

  The following phenomena were observed using a Ge (Li) detector whose resolution was already degraded by neutron irradiation : (1) The resolution of the detector gradually worsened after applying the bias voltage. However, it recovered when the detector was kept at zero bias for few hours. (2) Signals sometimes abruptly changed their positions toward lower energy sides after several minutes. They took about 10－100 minutes in order to return to their original positions. (3) A double-peaking phenomenon was observed when irradiated in an intense γ ray field.