A new radio spectral receiving system at mm in Urumqi Astronomical Station

¹ Department of Astronomy, Nanjing University, Nanjing 210093, PR China
² Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, PR China
³ Institute of Acoustics, Chinese Academy of Sciences, Beijing 100080, PR China
⁴ Urumqi Astronomical Station, Chinese Academy of Sciences, Urumqi 830011, PR China

Received: 18 January 1999
Accepted: 24 March 1999

Abstract

We describe a new radio spectral receiving system installed on the 25 m radio telescope of the Urumqi Astronomical Station in China. The receiver is conventional cryogenically cooled 22 GHz system, with the front end being a low noise HEMT amplifier. An average noise temperature of the receiver is about 50 K. The back end, however, is less conventional; it is a surface acoustic wave chirp transform spectrometer (SAW CZT), used for the first time in radio astronomy. As the prototype spectrometer, this system has a bandwidth of 40 MHz and 39.06 KHz frequency resolution. The observational results of water vapor masers demonstrate the feasibility of the SAW CZT-based spectrometer as astronomical spectral line observations.