The papers, data, and figures can be viewed and downloaded here:
For a more in-depth description of the BICEP2 instrument, please see this paper.
BICEP2 employs arrays of slot-dipole antennas coupled to low-temperature tranisiton edge sensor (TES) bolometers to detect the faint polarization signature of the cosmic microwave background. Shown here is the back side of the focal plane where the dipole arrays are visible.
BICEP2 is an on-axis refractor which is employs a combination of liquid Helium and a three-stage Helium sorption refrigerator to cool the detectors to 0.27 degrees above absolute zero.
The telescope was designed to be as compact as possible while still having the angular resolution to observe degree-scale features (where the inflationary B-mode signature peaks).
On-axis, refractive optics allow the entire telescope to rotate around the optical axis for polarization modulation.