TJ-II possesses a Lithium beam diagnostic. A thermal Li beam source, located at ∼ 80 cm from the observation region, has been used for the reconstruction of the SOL and edge parameters of the plasmas. A 16 channel photomultiplier array allowed the continuous recording of the radial profile of Li* emission. Detection of the Li* emission up to 8 cm inside the last closed flux surface (corresponding to r/a < 0.7) was possible.   
This diagnostic can no longer be used due to the use of Lithium for plasma wall conditioning, creating an overwhelming amount of Li background emission.
- B. Brañas et al., Atomic beam diagnostics for characterization of edge plasma in TJ-II stellarator, Rev. Sci. Instrum. 72, 602 (2001)
- F.L. Tabarés et al, Edge characteristics and global confinement of electron cyclotron resonance heated plasmas in the TJ-II Stellarator, Plasma Phys. Control. Fusion 43 (2001) 1023-1037
- F.L. Tabarés et al, Density control and plasma edge characterisation of ECRH heated plasmas in the TJ-II stellarator, Journal of Nuclear Materials 290-293 (2001) 748-752