Solar Submillimiter Telescope (SST) and Heliogeophysical Laboratory

The SST was built through an international cooperation initiative between the Centro de Rádio Astronomia e Astrofísica Mackenzie from Brazil and CASLEO. Other relevant Brazilian co-participants are Universidade Estadual de Campinas, the Instituto Nacional de Pesquisas Espaciais, the Universidade Federal de Rio de Janeiro and the Observatorio Solar "Bernard Lyot". The Instituto Lebedev de Física de Moscow (Russia) and, at the initial phase, the Universidad de Berna (Switzerland) have also collaborated. The funds for its construction were mainly provided by Fundação de Amparo a Pesquisa do Estado de São Paulo (Brazil) and the Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina) which are currently supporting its operation with the assistance of the Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil) and the Fondo Mackenzie de Pesquisas (Brazil) apart from the Air Force Office of Scientific Research (AFOSR) of the U.S.A.

SST

The main facility of the Heliogeophysical Laboratory is the SST, a radio telescope especially configured to observe the Sun. Its main goal is the analysis of solar flares or bursts, even though it can also be used to study the Quiet and Quiescent Sun. This instrument works at 212 and 405 GHz, which turns it into a unique instrument. At those frequencies, the wavelengths are 1.4 and 0.7 mm respectively, hence its submillimeter denomination.

The telescope is a Cassegrain system made up of a 1.5 m diameter aluminum primary mirror. At its focus there is an array of superheterodyne receivers which operate at room temperature: four tuned at 212 GHz and two at 405 GHz. The receivers were specially designed by Radiometer Physics GmbH from Germany. The mount of the telescope was developed by Orbit Advanced Technologies from Israel, and the whole assembly is protected by a Gore-Tex radome (dome) by ESSCO from the U.S.A. Data acquisition, antenna control and other auxilliary services were developed by the project's staff.

The SST was installed in April 1999 and it has been in continuous operation on a daily basis since 2001. Its focal array allows determination of the emitting source's instant position (although it is unable to make images). This capability and its high data acquisition rate (200 readings/s) have turned the SST into a unique instrument that has led to significant discoveries, v.g., a second spectral component during solar flares.

New experiments have been developed in the last few years to broaden the observational frequency coverage. One of these experiments consists of a 14 µm infrared camera installed at the focus of a Zeiss Jensch 300 celostate. A solar heliograph is also being installed and we hope to have radio receivers in the frequencies of 45 and 90 GHz in the near future.

Heliogeophysical Laboratory

Along with these instruments, a Heliogeophysical Laboratory was set up made up of VLF waves tracking stations, solar cosmic ray gauges and electric field gauges. The VLF waves receptors are part of a network of similar receptors installed in Brazil, Argentina and Peru, in a joint effort between the CRAAM (Brazil), Universidade Federal de Santa Maria (Brazil), Universidade do Vale do Paraiba (Brazil), CASLEO (Argentina), Radio Observatorio de Jicamarca (Perú), Universidad Nacional San Luis Gonzaga de ICA (Perú), Universidad de Piura (Perú), Universidad Nacional Mayor de San Marcos (Perú) and the Comisión Nacional de Investigación y Desarrollo Aeroespacial (Perú). The purposes of the South America VLF Network (SAVNET) include the study of the low ionosphere, the monitoring of the solar activity in different time scales, and the search for seismic-electromagnetic effects.

The cosmic ray detector (CARPET) monitors the flow of secondary particles produced by solar protons after the interaction with the earth atmosphere, and, therefore, it provides us with information about the evolution of long time scales of solar activity. In shorter scales, CARPET is used to study the impact of solar alterations known as Coronal Mass Ejections. Along with CARPET, an atmospheric electric field gauge is used to study the global atmospheric electric circuit.