We report on an efficient and compact high-flux Cs atom beam source based on
a retro-reflected two-dimensional magneto-optical trap (2D MOT). We realize an
effective pushing field component by tilting the 2D MOT collimators towards a
separate three-dimensional magneto-optical trap (3D MOT) in ultra-high vacuum.
This technique significantly improved 3D MOT loading rates to greater than 8×109 atoms/s using only 20 mW of total laser power for the source. When
operating below saturation, we achieve a maximum efficiency of 6.2×1011 atoms/s/W