Electromagnetic, thermal and structural analysis of the Fermilab antiproton source lithium collection lens

A coupled field finite element ANSYS analysis was done on the electromagnetic, thermal and structural aspects of Fermilab Antiproton Source lithium lens operation. The temperature distribution from Joule heating and the radial magnetic pinch forces were used as input for a 2-D structural model with a fine mesh density. The results of this analysis show that the preload on the lithium as it is filled into its titanium container may be reduced by 15 percent. This reduces the radial stress on the Ti can after the pulse when only preload and thermal stresses remain. Further reduction in preload could come from a scheme to pre-pulse the lens at low current. The heating of the lithium before standard operating current is applied would then play the role of preload at fill. The results of this analysis and future implications for lens operation will be discussed.