The Early Universe: Cosmic Foreground

In cosmology the Cosmic Microwave Background Radiation is considered a left over from an early stage in the formation of the universe and therefore the most direct and strongest evidence of the Hot Big Bang Model. This radiation shines primarily in the microwave portion of the electromagnetic spectrum.

This Radio Frequency is almost uniform in all directions. Some of the limitations of its measurements are the contamination by electro-magnetic emissions from our atmosphere and galactic plane as well as small anisotropies, or irregularities.

The Cosmic Foreground Explorer is a telescopebuilt to measure these fluctuations and irregularities. In order to understand the signals from the sky and measure the foregrounds we tested and calibrated the device will detect Radio Frequency signals. This instrument had several components:  horns, antennas, amplifiers and diodes.  

In a controlled environment these instruments were given an input in a Radio Frequency range of 6GigaHertz to 18GigaHertz. In order to amplify these signals we used and tested 10GigaHertz and 15GigaHertz amplifiers and to rectify the current and voltage oscillations we used diodes that gave an output of 1MilliVolt per 2.7microWatts Radio Frequency Power input. Looking at the sky at zenith the voltage output was 8MilliVolts or about 20MicroWatts and a temperature of 20 degrees Kelvin.

The instruments now are tested and built with enough sensitivity to detect a power input from our sky of 1.66 x (10^-13) Watts equivalent to -127 Decibels of Power relative to 1MilliWatt. Understanding the instruments are a key to precise measurements of cosmic background radiation and its irregularities, which are critical for the development of cosmological scenarios of origin and structure of the universe.