  In this paper, we report on the design and operation of the LongBo time
projection chamber in the Liquid Argon Purity Demonstrator cryostat. This
chamber features a 2 m long drift distance. We measure the electron drift
lifetime in the liquid argon using cosmic ray muons and the lifetime is at
least 14 ms at 95\% confidence level. LongBo is equipped with preamplifiers
mounted on the detector in the liquid argon. Of the 144 channels, 128 channels
were readout by preamplifiers made with discrete circuitry and 16 channels were
readout by ASIC preamplifiers. For the discrete channels, we measure a
signal-to-noise (S/N) ratio of 30 at a drift field of 350 V/cm. The measured
S/N ratio for the ASIC channels was 1.4 times larger than that measured for the
discrete channels.
