Kogut, Al2015-01-292015-01-292015https://hdl.handle.net/11299/169643The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne instrument to search for inflationary B modes on angular scales 30 arcmin to 90 degrees (2 < ell < 400). PIPER combines cold (1.5 K) optics, 5120 bolometric detectors, and rapid polarization modulation using VPM grids to achieve both high sensitivity and excellent control of systematic errors. A series of flights alternating between northern and southern hemisphere launch sites will produce maps in Stokes I, Q, U, and V parameters at frequencies 200, 270, 350, and 600 GHz (wavelengths 1500, 1100, 850, and 500 microns) covering 85% of the sky. We describe the PIPER instrument and discuss the current status and expected science returns from the mission.enFTPICMBPresentation