Hard X-rays and gamma-rays are important frequency windows for expoloring the energetic universe. Our knowledge about the universe is very limited in the energy region above several 10 keV where the non-thermal emission, produced by energetic particles becomes dominant. However, when compared with X-ray Astronomy, gamma-ray astronomy is still immature and significant improvements should be done to obtain sensitivity comparable to that achieved in the energy band below 10 keV. The sensitivity of observations with hard X-ray and gamma-ray detectors are limited by the background rate. The phoswich configuration and the narrow field of view obtained by a tight active “well-type” shield developed for the Astro-E Hard X-ray Detector (HXD) is the solution to achieve a very low background rate in the energy range up to several hundred keV. In this paper, we present concepts of gamma-ray mission in near future. The direction toward more sensitive mission in the energy region from hard X-ray to soft gamma-rays is also discussed.

  Niobium-based superconduting tunnel junctions (STJs) with aluminum trapping layers have been fabricated for X-ray ~ extreme ultraviolet (EUV) photons for application to astrophysics, particle physics, material physics, and so on. STJs are applicable as photon detectors with good energy resolution and a high photon-counting rate. STJs also have good efficiency because of their high absorption efficiency below 1 keV photon energy. That is advantageous in the observation of the faint objects with which the photon number is limited like planetary plasma and astronomical objects. We are particularly interested in using STJs as EUV imaging detector for observation of the planetary magnetosphere.

  STJs have potentials to open new windows of telescope. The combination of the improved optical elements and STJs will enable us to design a new optical system in the near future. We demonstrate the design combined Visible - X-ray wide range telescope.

  Lithium drifted silicon (Si(Li)) detectors with high-quality large area for charged particles spectrometer aboard artificial satellite have been developed. Surface stability can be obtained by thin p-n junction fabricated with the applied photo engraving process (PEP) instead of surface barrier. The region compensated with Lithium can be improved by the adequate heat treatment, and this improvement can be monitored by means of a combination of copper plating and subsequent micro-XRF analysis. The detectors fabricated from the thermal treated wafers were found to have better energy resolution both for α-particles from ²⁴¹Am and conversion electrons from ²⁰⁷Bi.

  The Real-time Radiation Monitoring Device (RRMD) is the only dosimeter that can give dose equivalent by direct measurement of LET distributions for space radiation. RRMD-III has the capability to measure LET of particles with wide range (0.2 ~ 600 keV/μm). The system and the dosimetric data on Space Shuttle Missions obtained by RRMD-III are summarized. And results of the comparison with the other dosimeters such as Tissue Equivalent Proportional Counter (TEPC) and DOSimetry TELescope (DOSTEL) are given.

  Since the dose levels in space are significantly higher than those on the ground, accurate dosimetric measurements have strongly been required for the radiation protection of astronauts and cosmonauts engaged in long-term space flights. Passive dosimeters such as TLDs and nuclear track detectors have frequently been employed from the beginning of the history of the manned space flights. CR-39 plastic is currently the most common passive detector for measuring LET distributions of heavy-charged particles in space radiation fields. Although CR-39 and TLDs are integrating types, they are still promising as space radiation dosimeters. The combination of data from both detectors allows us to estimate total radiation doses over an extremely wide LET range of the order from 10^-1 to 10⁴ keV/μm. We compare the dosimetric results from CR-39/TLD aboard STS-84 and STS-91 to those from RRRD-III to discuss the accuracy of the dose measurements. We emphasize that the measurement of short-range high-LET particles consisting of lower-energy trapped protons and nuclear fragments by CR-39 is quite important for improving the accuracy.

  The Imaging Plate (IP) has been used for the detector of electron spectrometer (ESM) at the Institute of Laser Engineering, Osaka University. ESM is a magnetic analyzer to measure hot electrons created through ultra-intense laser plasmas interactions of energies up to 100 MeV. However the energy response of IP is known only to less than 1.25 MeV. In the present study, we calibrated a response of an IP for 10 - 100 MeV electron beams by using the L-band linac and the S-band linac at the Institute of Scientific and Industrial Research, Osaka University. The data indicated that IP sensitivity for hot electron was nearly constant over 1 MeV.