Cascade transition x-rays from electron capture into highly charged ions in collisions with neutral gas targets

Using the electron beam ion trap (EBIT) and extraction facility at the National Institute of Standards and Technology (NIST), a series of systematic collision studies was performed with different projectile and target combinations. X-rays originating from a series of the cascades after electron capture into highly excited Rydberg states have been observed from low energy, highly charged Krq+ colliding with neutral Ar atoms. (R.P.)