The complete set of nested Chandra X-ray mirrors (4 shells with 2 segments - parabola and hyperbola - each) and their support structures make up the High Resolution Mirror Assembly or HRMA.

Possible Reference:
Van Speybroeck L.P., Jerius D., Edgar R.J., Gaetz T.J. & Zhao P., 1997, SPIE, 3113, 89.

See the POG for more details.

The CXC HRMA Calibration WWW pages have reports on the latest HRMA calibration status.