We are constructing a 10m-scale clock gradiometer with strontium atoms, spanning the height of a two-story lab. This device is a prototype for the even larger scale instrument MAGIS-100 and consists of a stack of two atomic fountains, and a common clock interferometry laser propagating in the shared vertical vacuum tube. Each fountain contains an atom source, a connection node, and a magnetically shielded vacuum tube segment.

Ensembles of ultracold strontium atoms are prepared in each atom source chamber using a two-stage magneto-optical trap followed by a dipole trap stage. Then the atoms are transported laterally to the connection node chambers using a set of optical lattices. From these chambers, both ensembles are launched upwards via additional sets of optical lattices. While the atoms are in ballistic free-fall, they are interrogated by laser pulses from interferometry laser.