The first major survey with the SPT—designed to find distant, massive, clusters of galaxies through their interaction with the CMB, with the goal of constraining the dark energy equation of state—was completed in October 2011.

In early 2012, a new camera (SPTpol) was installed on the SPT with even greater sensitivity and the capability to measure the polarization of incoming light.

The Pole's high altitude of 2.8 km (2,800 m; 1.7 mi; 9,200 ft) above sea level means the atmosphere is thin, and the extreme cold keeps the amount of water vapor in the air low.

It was designed to allow a large field of view (over 1 square degree) while minimizing systematic uncertainties from ground spill-over and scattering off the telescope optics.

The SPT-SZ camera was used primarily to conduct a survey of 2500 square degrees of the Southern sky (20h to 7h in right ascension, −65d to −40d declination) to a noise level of roughly 15 micro-Kelvin in a 1-arcminute pixel at 150 GHz.

The 150 GHz pixels were corrugated-feedhorn-coupled TES polarimeters fabricated in monolithic arrays at the National Institute of Standards and Technology.

[9][10][11][12][13][14][15] When combined with accurate redshifts and mass estimates for the clusters, this survey will place interesting constraints on the dark energy equation of state.

[10][16] Data from the SPT-SZ survey have also been used to make the most sensitive existing measurements of the CMB power spectrum at angular scales smaller than roughly 5 arcminutes (multipole number larger than 2000) [17][18] and to discover a population of distant, gravitationally lensed dusty, star-forming galaxies.

[19] Data from the SPTpol camera was used to make several groundbreaking measurements, including the first detection of the so-called "B-mode" or "curl" component of the polarized CMB.

[20] This B-mode signal is generated at small angular scales by the gravitational lensing of the much larger primordial "E-mode" polarization signal (generated by scalar density perturbations at the time the CMB was emitted)[21] and at large angular scales by the interaction of the CMB with a background of gravitational waves produced during the epoch of inflation.

[citation needed] The 1500-square-degree SPT-3G survey will be used to achieve multiple science goals, including unprecedented constraints on a background of primordial gravitational waves joint analysis of B-mode polarization with the BICEP Array, a unique sample of distant galaxy clusters for cosmological and cluster evolution studies, and constraints on fundamental physics such as the mass of the neutrinos and the existence of light relic particles in the early Universe.

Commissioning observations and an initial small survey were completed during austral winter 2007 with winter-overs Stephen Padin and Zak Staniszewski at its helm.

During the first season of observations, the winterover crew, Cynthia Chiang and Nicholas Huang, took data on a 100 square degree survey field.