Laboratorio de Instrumentación radiastronómica en Cerro Calán: hacia el desarrollo de alta tecnología en Chile

Bronfman, Leonardo


A mm-wave laboratory for the specialized training of graduate students and engineers has been set up at Cerro Calán Observatory. The installations include ample working space, regulated power installation for 110 V and 220 V, and antistatic carpeting for the floor and desks. The instrumentation purchased and installed include an Analog Signal Generator from 250 kHz to 20 GHz, a Microwave Frequency Counter up to 20 GHz, a Millimeter-Submillimeter Power Meter operating from 75 GHz to THz band, a 20 MHz Function Waveform Generator, a GPS Time and Frequency Receiver, and a Network Analyzer operating up to 26 GHz. This equipment allowed us to work on the upgrading of the 1.2 m mm-wave telescope receiver. In a first stage a new Local Oscilator was build based on a Gunn device. The Gunn is controlled by a PLL circuit which need a reference signal of about 5 GHZ, this signal was generated by the new Analog Signal Generator. Once the LO was build it was caracterized in the complete range of frequency (88-115GHz) with the PM3 Power meter. We discover that the Gunn generates enough power in the whole range, and it could drive the mixer without problems. Finally the new LO system was successfully integrated to the whole system. The second stage of the work was to include a HEMT amplifier as the receiver front end element. With this modification we expect an increase in the receiver sensitivity. The HEMT was integrated to the receiver using an isolator which prevent the generation of standing waves. Using the Microwave Frequency Counter - Power Meter we measured the noise temperature of the receiver. We got a noise temperature of 560ºK at ambient temperature which is a 30% lower than the 800ºK that the receiver had before the updating. The Network analyzer allowed us to test different components during the work and the GPS receiver provides a frequency standard to our laboratory.

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Fecha de publicación: 0
Año de Inicio/Término: 1/8/2005 - 1/12/2006
Financiamiento/Sponsor: ALMA-CONICYT