Two-dimensional imaging of neutral alkali atom samples using surface ionization

We describe the design and characterization of a high resolution, high efficiency detector for two-dimensional imaging of neutral atoms. Incident atoms are surface-ionized by a tungsten-coated hot ribbon and the resulting ions are accelerated into a microchannel plate detector with a phosphor screen output. With this design we can detect individual alkali and other low ionization potential atoms and molecules with a spatial resolution of ∼20 μ m . We find backgrounds on the order of 30 Hz over an active detection region of 20 mm 2 , a time response of ⩽1/30 s , and a detection efficiency of ∼50%. This detector can be used to image cold as well as thermal atomic or molecular beams.