2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/230066We explore the prospects of using the hyperfine transition of 3He+ as a probe of the intergalactic medium. The emission signal from ionized regions during reionization is expected to be anti-correlated with 21cm maps. The predicted emission signal from Lyman-alpha blobs at lower redshifts is detectable with future radio observatories.5 pages, 1 figure, submitted to MNRASCosmology and Nongalactic Astrophysicstext