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Place: Atomki, Bem ter 18/C, Debrecen, Hungary

Duration: 3 days

Maximum participants: 4

Desciption

The participants will gain practical knowledge about the measurements of certain plasma parameters with small-­size electrostatic probes (Langmuir-­probes). Among the various methods Langmuir probes are one of the most  important ones available for local plasma diagnostics.  In the Atomki ECRIS Laboratory two plasma devices are available the Table Plasma Generator (TPG) is a plasma device operating in a wide range of frequency producing low-­charged plasmas. There are no mirror coils, just a long radial permanent-­‐magnet hexapole magnet, and there are no beam extraction at all. However, very easy and fast to install any probes into it, the plasma is fully visible with our eyes. The other device is a classical 14.3 GHz ECRIS with B-­‐minimum geometry and with beam extraction for producing highly-­charged plasmas and beams. Langmuir-­probes can be installed into both devices. The measuring system consists of Langmuir‐probe (optionally movable), power supply, remote control unit, control software, analyzing software. The results of the measurements are several plasma parameters at the position of the probe, like floating potential, plasma potential, electron temperature, electron density, electron energy distribution function, effective temperature. The effect of ECRIS setting parameters (microwave frequency and power, gas type and pressure, etc.) to the plasma can also be studied by this method. In the first half of the training years the simplest (small-­‐size cylindrical) probes will be applied. In the second-­‐half other types (double probe, emitting probe) are also planned to be used - depending on the availability of the plasma sources and personal, that time.

Plan of activities

First day: The participants will attend in an introductive seminar about the measuring system and about the applied formulae (Chen, Libermann). Then they install one or two probes into the TPG. Pumping, ageing and taking current-­voltage characteristics with the measuring system. Calculating plasma parameters from the characteristics with analyzing software. Studying the effect of some setting parameters.

Second day: If the 14.3 GHz ECRIS is not available than continuing the first day program with the TPG. Studying the effect of the microwave and the probe position. If available, 2-­frequency plasma. If the 14.3 GHz ECRIS is available with a pre-installed Langmuir-­probe (the installation is carried out by local personnel days before the training) than taking I‐U characteristics of highly charged plasma with simultaneous beam extraction.

Third day: Continuing the program of the 2 previous days, summarizing the results, compiling together a detailed PowerPoint summary of the 3 days results.

Presentation:

 Measurements of ECR plasma parameters by Langmuir-probes 

Report on ATOMKI hands-on-training: can be seen here

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