CII tomography is a promising approach to study the populations of galaxies
responsible for reionizing the Universe in the first billion years after
the Big Bang. Deep UV dropout surveys in small fields shown that the EoR
galaxies are intrinsically faint, even on the scale of the deepest Hubble,
JWST, and ALMA surveys. The luminosity functions show steep and/or
uncertain faintend slopes, so that the total integrated light is poorly
constrained. We are pursuing wide-field spectroscopic instrumentation for
measuring the 3-D clustering via intensity mapping in the 1- mm band, which
is sensitive to [CII] at z=5-9. With a survey sufficiently wide to measure
the 2-halo clustering term on tens of arc minute scales, this technique is
sensitive to the luminosity function integral, and thereby measures the
total star-formation rate since [CII] broadly traces star-formation
activity. TIME-Pilot is designed for a first measurement of this signal
with an experiment that is tractable with existing technology. 32 waveguide
spectrometers disperse the 183-326 GHz band at R 100 to arrays totaling
1840 TES bolometers. TIME-Pilot will be deployed to the JCMT, and the
survey volume will consist of an on-sky footprint of 1 degree by 1 beam,
with depth provided by the spectral coverage. Our models indicate that the
raw sensitivity of TIME-Pilot is sufficient to provide a detection of the
[CII] clustering signal in a couple of hundred hours on sky. However, the
dominant signal in the experiment will be the CO-emitting galaxies at z 0.5
to 3. This signal is interesting in its own right, but will need to be
measured and removed to reveal the [CII]; we are developing strategies for
this.