| Project/Area Number |
05452196
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | Nagoya University |
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Principal Investigator |
GOTO Toshio Nagoya University, School of Engineering, Professor, 工学部, 教授 (50023255)
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| Co-Investigator(Kenkyū-buntansha) |
KISHIMOTO Shigeru Nagoya University, School of Engineering, Reseach Assistant, 工学部, 教務職員 (10186215)
KONO Akihiro Nagoya University, School of Engineering, Associate Professor, 工学部, 助教授 (40093025)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1994: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1993: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | Cu / metastable atoms / diffusion coefficient / electron collisional de-excitation / saturated absorption spectroscopy / copper vapor laser / laser absorption spectroscopy / 銅原子 / 拡散定数 |
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| Research Abstract |
In the powerful and highly efficient copper vapor laser, the lower levels of the laser transitions are metastable states. The detailed knowledge of their relaxation processes is therefore of practical importance to improve the laser performance. In this study the diffusion and electron-collisional de-excitation processes for the metastable copper atoms were investigated, which determine the lifetime of the metastable atoms in the discharge.
Copper vapor was produced in a discharge tube with a copper hollow cathode by cathodic sputtering. The diffusion coefficients for metastable copper atoms in Ne and Ar were determined from their density decay in the afterglow measured by using laser absorption spectroscopy. The diffusion coefficients for ground-state copper atoms in He, Ne, Ar were also determined by using absorption spectroscopy with a copper hollow cathode lamp used as a light source. It was found that the diffusion coefficients for the metastable and the ground-state copper atoms w
… More
ere essentially of the same magnitude, contrary to a reported result.
A new method was developed to determine the lifetimes of metastable atoms in a steady-state discharge. The method is based on saturated absorption spectroscopy, in which a strong pump laser beam excites metastable atoms and a weak probe beam measures the reduction of their population due to the pump beam ; the analysis of the results with the aid of rate equations enables one to determine the lifetime of the metastable atoms. As was demonstated by experiments, the long lifetime of metastable atoms prevents the pump beam from causing hole burning in the velocity distribution of the atoms through collisional mixing of the populations with different velocities ; this allows one to use the rate-equation analysis. The obtained lifetime of the metastable copper atoms decreased with increasing discharge current. This indicates that their lifetime is mainly determined by electron-collisional destruction rather than by diffusion. This method of determining metastable-atom lifetime can be combined with electron density and temperature measurements to yield de-excitation rate constant for metastable atoms. Less
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