1990 Fiscal Year Final Research Report Summary
Electronic Structures of Metallic Cerium Compounds Studied By Photoelectron Spectroscopy and Bremsstrahlung Isochromat Spectroscopy
| Project/Area Number |
01540279
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
HANYU Takaaki Tokyo Metropolitan Univ. Dept. of Physics Professor, 理学部, 教授 (30087093)
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| Co-Investigator(Kenkyū-buntansha) |
ISHII Hiroyoshi Tokyo Metropolitan Univ. Dept. of Physics Research Assistant, 理学部, 助手 (90128562)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Monochromator / PES / Electron gun / Kondo resonance state / BIS / Density of states / Electron lens / Dense kondo alloy |
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| Research Abstract |
The construction of a combined spectrometer has been planned in order to obtain the information about the electronic structures just below the Fermi level for metallic cerium compounds. This apparatus consists of a photoelectron spectrometer (PES) and a bremsstrahlung isochromat spectrometer (BIS). Of this apparatus the PES has been completed and has been well operated. In this time it is to design and construct the BIS. This consists of the monochromator for AlK alpha radiation and the electron gun system for excitation. Firstly, the monochromator has been designed, in which some quartz plates are used for monochromatization of radiation from samples. In order to collect the radiation as much as possible, a multi-bent quartz crystals has been designed. A radius of the bent quartz crystal is 400 mm. The system of adjustment for position of the crystals has been constructed ; for the movement and inclination of the samples.
Next, we have designed an electron gun. For the determination of
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the design, the computer program for calculating an electron trajectory has been researched and developed. Based on the ray-tracing, a lens system has been so determined as to be suitable for BIS. The final design of the electron lens consists of a part of electron emission gun and three-cylindrical electrode lens for focusing electron beam and acceleration of electrons. The specification of the electron gun system is as follows ; (1) Acceleration of voltage for electron can be varied from 10 to 1,500 eV, (2) The focal spot size on sample is less than 2 mm phi , and (3) The current of electron beam can be obtained as much as possible. It is very difficult to realize the third specification, because the emission source must be warmed too high for obtaining the high beam current. Then, the vacuum of the chamber including the electron gun grows worse because of the high beam. The consideration for this dilemma is important for designing the electron gun ; The limit of the beam current occurred.
The electron gun and quartz monochromator are to be assembled in the chamber having a vacuum of less than of 1 x 10^<-10> Torr, and the combined spectrometer is scheduled to be complete for measuring the density of states in the occupied and empty bands of the materials concerning to 4f electrons. Less
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