Marshall Imaging X-ray Experiments (MIXE)

MIXE was a large-area hard-X-ray proportional counter. It featured a mechanical collimator that only allowed X-rays from a narrow region of the sky to reach the detector where the X-rays photoionize the Xe fill gas (see diagrams below). The photoelectron released in this process drifts through the chamber, driven by an applied electric field, onto a microstrip detector where its position and energy are recorded. Along the way, the photoelectron causes further ionization in the chamber resulting in a small electron cloud, thus amplifying the electrical signal at the microstrip detector.

MIXE flew in several campaigns in the 1990's. It has since been supplanted by MSFC's hard-X-ray focusing optics program.

Click on images below for enlarged views