Development of Mossbauer scattering and diffraction methods with a high density source

Research Project

Project/Area Number	60460039
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	物性一般（含極低温･固体物性に対する理論）
Research Institution	Osaka University
Principal Investigator	KUNITOMI Nobuhiko Osaka University, 理学部, 教授 (40028072)
Co-Investigator(Kenkyū-buntansha)	MITO Asae Osaka University, 理学部, 教務員 (50127304) KAWARASAKI Syuzo Osaka University, 理学部, 助手 (40028262) TSUNODA Yorihiko Osaka University, 理学部, 助手 (70028215) FUKUSHIMA Syozo Osaka University, 理学部, 講師 (10028136) NAKAT Yutaka Osaka University, 理学部, 助教授 (10028178)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥7,900,000 (Direct Cost: ¥7,900,000) Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1985: ¥7,400,000 (Direct Cost: ¥7,400,000)
Keywords	Small angle scattering of Mossbauer <gamma> -rays / メスバウア線源の再処理法
Research Abstract	Our main project is to overcome the difficulties on using a high density <^(57)Co> source for the purpose of the Mossbauer scattering or Mossbauer diffraction experiments. New method of small angle scattering of Mossbauer <gamma> -rays was also tried to be developed. The <^(57)Co> source emits the high energy <gamma> -rays of about 700 keV, together with the low energy <gamma> -rays and the Mossbauer <gamma> -rays of 14.4 keV. Since the high energy component is small fraction of all <gamma> -rays emitted from the source, it is usually ignored on the design of the shield. However, the present source has very high activity and the high energy components make serious effect. After the preliminary measurements of the shielding effect, the shield boxes were constructed for the driving unit of the Mossbauer effect instrument and for the handling instrument of reprocessing the source, as mentioned below. In order to remove the self-absorption effect caused by the decay-products of <^(57)Fe> in the <^(57)Co> source, the procedures on the chemical separation of <^(57)Fe> from <^(57)Co> and on the heat treatment have been tried. Finally, the best method of the chemical separation has been found, but the problem of the diffusion of <^(57)Co> into the disk during the heat treatment is remained. Taking advantage of the variation of the energy width of the source, the small angle scattering experiment with the varying energy resolution was tried. Although the conclusion has not obtained because of the poor statistical accuracy, it will be possible to distinguish two models which give the same results of the small angle scattering experiment of neutrons.