Abstract Details
| Name: Saurabh Singh Affiliation: Raman Research Institute Conference ID: ASI2015_673 Title : Precision receiver for detection of redshifted 21cm signal from the Epoch of Reionization Authors and Co-Authors : Ravi Subrahmanyan, N.Udaya Shankar Raman Research Institute, CV Raman Avenue, Sadashivanagar, Bangalore 560080, India rsubrahm@rri.res.in, uday@rri.res.in Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : Red shifted 21 cm from the Epoch of Reionization is one of the key tools to study first stars and galaxies. It is technologically challenging to achieve the high dynamic range required to detect this signal of a few mK in the presence of bright galactic and extragalactic foregrounds. In this presentation, we discuss the system architecture developed by us for the detection of global redshifted 21 cm signal in the frequency range 40-250 MHz using a broadband precision spectrometer and a frequency independent disk-cone antenna. The present system measures differential temperature between the antenna and a known reference load. Bandpass calibration is achieved by coupling a switched noise source into the signal path. Another dedicated noise diode is used to make in-situ measurement of antenna impedance and its mismatch to free space. We have carried out extensive laboratory tests to estimate the performance of the system and Monte Carlo simulations to study the effectiveness of the data analysis methods adopted for the detection. We demonstrate that the system is capable of detecting signals of a few mK. Our approach to data analysis and preliminary results from the first sky observations using the system will also be presented. |