68Cs

68Cs, or cesium-68, is an isotope of the element cesium (atomic number 55) with a mass number of 68. It lies on the proton-rich side of the nuclear chart, well away from the valley of stability, and is not found in nature. If produced in the laboratory, 68Cs would be extremely short-lived according to current nuclear-model predictions, reflecting the general instability of light, proton-rich cesium isotopes.

Predicted decay modes for 68Cs include beta-plus decay (or electron capture) to a lighter xenon isotope, such as 68Xe. If the nucleus lies beyond the proton drip line, proton emission to lighter species, potentially 67Xe, could also occur. The exact decay pathway and half-life depend on the energy balance (Q-values) and the proximity to the drip line, making precise measurements challenging.

Production of 68Cs would come from high-energy nuclear reactions, typically in facilities that produce rare-isotope beams. Methods such as projectile fragmentation of heavier, proton-rich nuclei or related fusion-evaporation reactions could, in principle, generate extremely short-lived cesium-68 fragments. Detection relies on rapid separation and identification using time-of-flight, energy loss, and magnetic rigidity measurements, combined with fast detectors.

As an extremely proton-rich, short-lived nuclide, 68Cs has limited practical applications and serves mainly to inform nuclear structure models and the understanding of the limits of nuclear binding. It complements studies of more stable cesium isotopes, such as Cs-133, and helps map the behavior of nuclei far from stability.