Recently, a direct X-ray detection CCD is widely employed in measuring of X-ray image and spectrum. In X-ray astronomy satellite, CCD for X-ray photon count becomes a standard detector. We summarize the performance of the CCD for X-ray use in space. The calibration before launch is carefully done using various X-ray sources in order to establish the precise response function. CCD in space will experience the radiation environment that substancially degrades the performance. There are several measures to reduce the radiation damage. A charge injection method is explained, which surely compensate the performance. A mesh technique is introduced to measure the CCD response with sub pixel resolution. It enables us to directly measure the charge cloud shape generated by an X-ray photon inside the CCD. Since the charge cloud sometimes splits into adjacent pixels forming split pixel event, we can determine the X-ray landing postion inside the CCD with sub pixel resolution.

  We have been conducting an R&D project to realize a one-dimensional microstrip Germanium detector for the Compton spectroscopy performed in the energy region around 80 keV at the SPring-8 facility. During the course of carrying out the R&D project, the number of the microstrips has been gradually increased, by ensuring the spatial resolution, the energy resolution, the full-energy peak efficiency and so on. The current model of the one-dimensional microstrip Germanium has 128 strips with a width, an interstrip, and a height of 300μm, 50μm, and 40mm, respectively. Four VA-TA chips are incorporated as a front-end-readout circuit to read out the charge collected on these strips. Compton profiles of aluminum have been successfully observed with the current model, which demonstrates the superiority of the one-dimensional microstrip Germanium detector to conventional slit-scanning type detector systems, especially, for those samples the X-ray scattering intensities of which are low. The detector technology established by the project expects to find various applications in different fields of science and industry, where the position determination is needed for high energy X-rays together with the energy determination.

  A Fast scanning X-ray CT system was developed to visualize dynamic motion of interface in multi-phase flow. The scanning time less than 4msec. was achieve by using 18 pulsed X-ray generators and highly sensitive 256-pixel CdTe line sensor modules. The sensor device technology is based on their prototypes previously assembled for high-resolution radiography and tomography imaging of electronic parts. Equipped with the above CdTe modules, the fast X-ray CT system was able to visualize the 50mm diameter cross section with a spatial resolution of 2.8mm. When the system was applied to an air-water two-phase flow and a simplified fluidized bed system, it successfully quantified the multi-dimensional characteristics of interface in flow.

  CdTe and CdZnTe are expected as the conversion layer for X-ray fluoroscopy, because they have higher sensitivity for X-ray compared to other conversion material. We made a prototype flat panel X-ray detector utilizing polycrystalline CdZnTe film, and evaluated its imaging performance with respect to leakage current, X-ray sensitivity and DQE. The detector incorporates a novel hybrid technique in which zinc-doped CdTe is pre-deposited onto a ceramic substrate and then connected with a TFT circuit substrate. The film thickness was about 300 um. The imaging area is composed of 512 x 384 pixels, with a pixel pitch of 150 mm. The measured leakage current was 90 pA/mm², and the sensitivity was 9E8 e-/mR/mm² at the bias field of 0.4 V/um; the beam condition was 80 kV with 26-mm Al filtration. The DQE at 0 lp/mm was 0.34. The value of DQE will be improved further by increasing the thickness or density of the CdZnTe film. Although further improvements are required in DQE, the superior X-ray sensitivity is promising in terms of using the detector in fluoroscopic mode, because the electronic readout noise becomes relatively negligible.

  Diamond radiation detectors have several merits in terms of high radiation resistance, high temperature operation, tissue equivalent, high chemical resistance etc. Moreover, the diamond radiation detector can be applied to a 14 MeV neutron energy spectrometer using ¹²C(n, α) ⁹Be reactions. The author has been developing synthetic diamond radiation detectors aiming at a 14 MeV neutron energy spectrometer, a charge particle detector for high temperature environment and soft X-ray measurement on fusion experimental reactors. In this article, the present status of the development and problems of synthetic diamond radiation detector were described.

  We described the detectors which used compound semiconductor materials (TlBr, PbI₂ and BiI₃) except CdTe.

  In this report, nuclear radiation detectors have been fabricated from the TlBr, PbI₂ and BiI₃ crystals. These are attractive materials for room temperature radiation detectors because of their wide band gap energies and high photon stopping power.

  The TlBr crystal was grown by horizontal traveling molten zone (TMZ) method. The FWHM (full width at half maximum) for the 59.5, 122 and 662keV γ ray photo peak were obtained as 3.3, 8.8 and 29.5keV at room temperature, respectively.

  In the case of the PbI₂ radiation detector, pulse height spectra for 59.5ke V γ-rays from the ²⁴¹Am source were experimentally observed with the detector fabricated from the sample grown by the TMZ method. Energy resolution of 5.1 keV FWHM was obtained.

  BiI₃ crystals were grown by using commercially available powder by the vertical Bridgman technique. Energy resolution of 2.2MeV FWHM for 5.48 MeV (²⁴¹Am) α-particles was obtained by the radiation detectors fabricated from the BiI₃ crystals.