Speaker
Description
Recently the C12A7 electride attracts much attention as one of the possible plasma electrode material of Cs-free negative hydrogen isotope (H⁻/D⁻/T⁻) ion sources[1-2].
In this work, H-/D⁻ spectra from a C12A7 electride target immersed in an ICP plasma was measured in the apparatus, Phisis[3] . The target was biased negatively against the electrically grounded chamber. The temperature of the target was controllable up to 800 C. Negative ions were energy analyzed by a Hiden EQP300 mass spectrometer. By rotating the target, it can be irradiated by an energy-tunable photon beam, Omni Lamda 300i[4], when the plasma off, and the photo-electric current was measured. The work function of the sample can be obtained from the threshold photon energy. The lowest value of the work function observed was ~2.5 eV. This value was confirmed by UPS measurement with the similar conditioning procedure.
Change of the negative ion yield due to the work function was measured.
[1] Y. Toda, et al., Advanced Materials 19, 3564 (2007).
[2] M. Sasao, et al., Applied Physics Express 11, 066201 (2018).
[3] G. Cartry, et al., A, New Journal of Physics 19 025010 (2017).
[4] L. Tahari, et al., presented at JSI 2020 - Journées Surfaces & Interfaces(Sorbonne Université, 22-24 janvier 2020).
