We have trapped positrons, and slowed and cooled them by collisions with N_2 buffer gas and CF_4 cooling gas. The images are 3D plots of the positrons detected on a phosphor screen (see banner at the top of the page).
The left-hand image shows the image resulting from the positron beams impinging on the phosphor screen, passing directly through the trap. The trap shows the distribution with a dip in the centre (see this post for an explanation of where this comes from). The right-hand image was generated by accumulating and cooling positrons in the trap for 1 second. The cloud of trapped positrons is then bunched and accelerated out of the trap and onto the screen.
Next step: we will accelerate these positrons onto a porous target and make positronium!