| Autor: |
Jo, Jong Gab, Jeong, Seung Ho, Kim, Tae-Seong, Kim, S. H., Park, Min, Huh, Sung-Ryul |
| Předmět: |
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| Zdroj: |
Physics of Plasmas; Sep2021, Vol. 28 Issue 9, p1-9, 9p |
| Abstrakt: |
The optimization of 2.45 GHz microwave coupling in an electron cyclotron resonance (ECR) ion source is investigated through experiments and full wave simulation studies. The axial magnetic field profile and an impedance transformer are the two major factors affecting the optimum power coupling. Experimental observations have shown that the beam current density increases when the two ECR zones are located in the plasma chamber and when the first ECR zone is close to the RF entrance. A coupling study with various magnetic field profiles finds that the gap distance between the RF window and first ECR zone and the effective ECR zone width determines the coupling efficiency. Optimum power coupling is obtained under the condition of an appropriately slight gap distance comparable to the half width of the effective ECR zone. The extracted beam current density increases when the second ECR zone becomes closer to the plasma grid. With the optimized axial magnetic field profile, impedance transformers are designed in consideration of reflection coefficient with respect to the plasma density. The performance of the impedance transformers is experimentally evaluated in terms of the efficiency (mA/W) with the findings consistent with the results of a simulation. The highest beam current density (∼165 mA/cm2) in these experiments is achieved with the optimized axial magnetic profile and the impedance transformer. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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