Abstract

With the puchase of a vacuum pump and leak detector and its successful testing and installation we have increased the capacity of carrying on millimeter and submillimeter receiver development projects in the laboratory at Cerro Calán. We have installed and set up a leak-free vacuum system necessary to cool down the 115 GHz receiver to liquid nitrogen temperature. The vacuum pressure achieved was 2E-3 [mbar] on steady state with the receiver cooled to 77 K. We also measured the noise temperature (NT) of the modified receiver in the frequency band between 90 GHz and 115 GHz. obtaining that the present usable band for astronomy is 93 GHz - 115 GHz, while previously it was 109 GHz – 115 GHz. The preliminary measured NT is of ~180 K between 105 and 115 GHz. The expertise gained throughout this project, specially related to vacuum and HEMT’s technology, will be decisive in the incoming projects. The recently funded construction of the ALMA’s Band 1 receiver prototype in our laboratory, will require a deep knowledge in vacuum technology to meet the ALMA standards. ALMA Band 1 receivers will also use HEMT amplifiers similar to the one mounted in our 115 GHz receiver, so the work done in this project it is considered an excellent start-up for our graduated students who will develop part of the prototype.