Measurement of the distance to gamma-ray burst surces

Research Project

Project/Area Number	06640356
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Astronomy
Research Institution	Kanagawa University
Principal Investigator	YOSHIDA Kenji Kanagawa University Faculty of Engineering Research Associate, 工学部, 助手 (90260984)
Co-Investigator(Kenkyū-buntansha)	KASHIWAGI Toshisuke Kanagawa Univ.Faculty of Engineering Lecturer, 工学部, 専任講師 (40202006)
Project Period (FY)	1994 – 1995
Project Status	Completed (Fiscal Year 1995)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000) Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	Radiation sensor of a diamond / Soft X-ray detector / Gamma-ray bursts
Research Abstract	Soft X-ray photons below 1 keV are required to observe the hydrogen column density to gamma-ray burst sources from which we can measure the distance to the source. A low leakage current of the X-ray detector is required to detect such a soft X-ray photon. Unlike silicon, high purity diamond exhibits a very high natural resistivity. Diamond also has a very large energy band gap of 5.5 eV compared with that of silicon of 1.1 eV.Thus, even with the application of a high electric field, only a feeble current flows through the detector. We produced the radiation sensor from several kinds of diamonds such as natural diamonds, chemical vapor deposited (CVD) diamonds, and high pressure synthesized diamonds. As a result, it was found that the sensor of a high pressure synthesized diamond has the excellent energy resolution of 25.4 keV (FWHM) for 5.486 MeV alpha particles from ^<241>Am, which ismuch better than the previously reported value of 82 keV (FWHM) of the natural diamond. The obtained energy resolution is almost the same as silicon sensor and a promising data for the future X-ray detector of gamma-ray bursts.