MRI: Track 2 Development of a Next-Generation Camera for High-Frequency and Spectroscopic Surveys with the South Pole Telescope

The current cosmological model for a theory of the Big Bang still leaves open a question how the entire observable Universe being spawned in a dramatic, exponential "Inflation" from a sub-nuclear, microscopical volume to the current macro-scale volume of spacetime. While extraordinarily sensitive measurements of the Cosmic Microwave Background (CMB) radiation (temperature and polarization at mm/sub-mm wavelengths) are traditionally associated with large CMB surveys, the ultra-deep “sky maps” are crucial for exploiting the full power of new cosmological observables and provide groundbreaking constraints on the duration and timing of the Big Bang’s short Inflation period and the follow-on Epoch of Reionization.

The new-generation SPT-3G+ camera will be used to produce a survey of the mm/sub-mm sky with an unprecedented combination of area, sensitivity, and angular resolution. These measurements will cover the same sky as the ongoing SPT-3G and BICEP-Array surveys, but the resulting maps will provide new insights into the Epoch of Reionization, the growth of structures in the Universe, improve constraints on cosmic Inflation, and provide a new window into mm/sub-mm Galactic and extragalactic astrophysical transients.

This award will support the construction of a new camera, SPT-3G+, that will have unique capabilities not provided by any planned instrument. SPT-3G+ will enable extraordinarily sensitive measurements of the temperature and polarization of the mm/sub-mm wave sky, extending the ultra-low-noise, wide-sky-area observations traditionally associated with large CMB surveys to include frequencies above the peak of the CMB blackbody emission curve.

This work builds on the experience and successes of the SPT team, which has built three cameras for the SPT and used them to produce high-impact studies of the CMB. In addition to the proposed mm/sub-mm survey, the SPT-3G+ camera will provide a platform for innovative instrumentation with the potential for new probes of astrophysics and cosmology, including in the burgeoning field of mm-wave line intensity mapping.

Finally, the SPT-3G+ camera and optics are designed to allow the SPT to continue its crucial role as part of the Event Horizon Telescope (EHT). The proposed activities will include a junior college internship and mentoring program, that will involve students from non-traditional backgrounds in the development, integration, and testing of the SPT-3G+ camera.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.