  We have built and commissioned gas absorption cells for precision
spectroscopic radial velocity measurements in the near-infrared in the H and K
bands. We describe the construction and installation of three such cells filled
with 13CH4, 12CH3D, and 14NH3 for the CSHELL spectrograph at the NASA Infrared
Telescope Facility (IRTF). We have obtained their high-resolution laboratory
Fourier Transform spectra, which can have other practical uses. We summarize
the practical details involved in the construction of the three cells, and the
thermal and mechanical control. In all cases, the construction of the cells is
very affordable. We are carrying out a pilot survey with the 13CH4 methane gas
cell on the CSHELL spectrograph at the IRTF to detect exoplanets around low
mass and young stars. We discuss the current status of our survey, with the aim
of photon-noise limited radial velocity precision. For adequately bright
targets, we are able to probe a noise floor of 7 m/s with the gas cell with
CSHELL at cassegrain focus. Our results demonstrate the feasibility of using a
gas cell on the next generation of near-infrared spectrographs such as iSHELL
on IRTF, iGRINS, and an upgraded NIRSPEC at Keck.
