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Bolocam is a millimeter-wave camera constructed for cosmology for the Leighton Telescope at the Caltech Submillimeter Observatory.  It is a large-format bolometric camera for observations between 1.1 and 2.1 millimeter wavelengths, utilizing a total of 144 Bolometers.  Bolocam is a collaboration between the California Institute of Technology (Observational Cosmology ), the University of Colorado in Boulder, the Jet Propulsion Lab (JPL), the Large Millimeter Telescope project, and Cardiff University.

Observations at 1.1 mm are sensitive to thermal emission from dust grains in regions of star formation, both in the Milky Way and in distant galaxies.  In collaboration with the Spitzer Legacy Cores-to-Disks team we are surveying the Perseus, Serpens, and Rho Ophiuchus molecular clouds to measure the dust emission in the vicinities of protostars and young stars.  When combined with the Spitzer far-infrared data, the Bolocam observations will enable the temperatures of the dust to be measured and the total gas mass heated by the stars to be estimated.  We are also using 1.1 mm Bolocam observations to detect submillimeter galaxies, which are high redshift (z>1) galaxies with extreme luminosities (>10^13 solar luminosities) and star formation rates (~10^3 solar masses per year).

2.1 mm observations are sensitive to secondary anisotropies in the 2.73 K cosmic microwave background
radiation.  Using Bolocam, we are surveying two regions of sky to try to detect secondary anistropies to constrain the dark matter and dark energy content of the Universe, as well as begin to measure the numbers, masses, and eventually redshift distributions of galaxy clusters, which give rise to the secondary anisotropies.

Bolocam is fully commissioned and observing proposals are being accepted by the CSO (see for procedures and policies).

This is the Bolocam instrument mounted with the cryogenic housing.  Here it is seen with the Caltech Submillimeter Observatory.  Click to enlarge.

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Here is the array of the 144 silicon nitride micromesh bolometers that make up Bolocam.  Each of these are spider web bolometers 5mm in diameter.  The silicon wafer is 300 microns thick.  These are described in Infrared Bolometers with Silicon Nitride Micromesh Absorbers (Bock et al., 1996, ESLAB Symp. Proc., and references therein).

The Feedhorn is used to concentrate radiation to each of the bolometers. 
Pictured is the 2.1 mm hornplate.