International Conference on Ion Sources (ICIS2021)

H$^-$ and D$^-$ Production Efficiency in a Multi-Dipole ECR-Plasma Source

Not scheduled

20m

Poster Negative ion sources Poster Session 2

Speaker

Ms Maria Mitrou (High Voltage Laboratory, Electrical and Computer Engineering Department, University of Patras, Rion-Patras 265 04, Greece)

Description

The ECR negative ion source “Prometheus I” is operated either with high purity H$_2$ ($>$ 99.999\%) or $D_2$ $>$ 99.8\%) in order to probe H$^-$ and D$^-$ ions, respectively, and examine the effect of the isotope upon their production. These ions are predominantly formed in the plasma bulk by dissociative attachment of low-energy (cold) electrons to highly ro-vibrationally excited molecules which in turn result mainly from the EV process sustained by high-energy (hot) electrons confined in the ECR zones. Langmuir probe and laser photodetachment measurements, realized in the pressure range 1 to 20 mTorr and for deposited power up to 900 W, reveal briefly: (i) higher and only slightly increased cold electron density and temperature in deuterium; (ii) no pronounced difference in the hot electron density and temperature; and (iii) overall a similar negative ion yield (up to 6$\times$ 10$^{15}$ m$^3$. Finally, the $n_{H^-}/n_e$ ratio is constantly higher than the $n_{D^-}/n_e$ one.

Presentation materials

POSTER_160.pdf