A High Resolution Disk Chopper with Two-Stage Rotors for Neutron Time-of-Flight Spectroscopy
Grant-in-Aid for Scientific Research (B)
|Research Institution||KYOTO UNIVERSITY|
ONO Masayoshi KYOTO UNIVERSITY,Research Reactor Institute, Assistant Professor, 原子炉実験所, 助手 (70027415)
|Project Fiscal Year
1996 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥8,300,000 (Direct Cost : ¥8,300,000)
Fiscal Year 1996 : ¥8,300,000 (Direct Cost : ¥8,300,000)
|Keywords||Neutron Spectrometer / Neutron Disk Chopper / Bent Si Single Crystal Monochromator / Time-of-Flight Method / Neutron Scattering / Residual Stress / Industrial Materials / Metal Matrix Composites / 中性子分光器 / 中性子デイスクチョッパ / 彎曲Si単結晶モノクロメータ / 中性子飛行時間法 / 中性子錯乱・回折 / 残留応力 / 工業材料 / 金属基複合材料 / 中性子散乱・回析|
The objectives are to establish the novel version of the four kinds of Bragg scattering set-ups installed at the supermirror neutron guide hall in Kyoto University Research Reactor (5 MW,light water moderated) : i.e.the three set-ups are time-of-flight diffractometers with point detectors using neutrons from a disk chopper (TOF), and the rest set-up is a crystal diffractometer with two one-dimensional position sensitive detectors with use of neutrons from a pyrolytic graphite monochromator (PSD).
1.TOF System : A novel disk chopper with two-stage rotors was designed and constructed based on the calculation of neutron transmission probability. The spectrometer was optimized with the measurements of standard sample Fe-Cr-Ni, alpha/gamma two phase steel, and supplied for the common studies by researchers from universities in Japan after its establishment, Nov.1996.
(1)Performance Tests :
(1)-1.Neutron wavelength resolution and its intensity became 2.5 and 3.3 times highe, resulting about 8 t
imes improvement of the diffractometer.
(1)-2.The samples of alpha/gamma steels and SiCw/Al were examined to verify the strain measurements of the crystal lattice specings over 10^<-3> to 10^<-4>. The gauge volume defined by the slit system before and after the sample was 2x30 in mm.
2.PSD System : The several Si single crystals (311), i) 3x30x200, ii) 4x30x200 and iii) 4x30x200, two layrs (in mm), were used for the optimization of the monochromator device. The beam profiles of the monochromatic neutrons were characterized by the Neutron Imaging Plate method. The absolute value of the neutrons was determined by the Au-foil Activation method. The performance tests of the ststerm were carried out with the standard samples of alpha Fe.
(2) Performance Tests :
(2)-1.The quasi-parallel diffraction pattern from alpha Fe (211) was obtained and its FWHM was 11.4' which was consistent with the prediction.
(2)-2.The angular resolution and the diffraded intensity were improved to be 10-15 times higher with repect to the conventional mosaic crystal of pyrolytic graphite monochromator.
Research Output (14results)