Installation of a Front End in a Japanese antenna
Tuesday, 14 October 2008
On 13 and 14 October, a Front End produced in North America was successfully installed into a Japanese 12-m antenna located at the ALMA Operations Support Facilities (OSF), thanks to a joint effort of the AIV (Assembly, Integration and Verification) Department of ALMA, the National Astronomical Observatory of Japan (NAOJ, the Japanese Partner of ALMA), and Site teams. This antenna, the ACA #2, is currently in a 'shared use' agreement between NAOJ and ALMA, allowing part time use of the antenna by AIV for initial integration efforts of component systems.
The installation of the Front End is a very delicate operation and follows an intricate procedure to gently lift the 500 kg weight of the equipment (using both a crane and a telehandler) to the receiver cabin and then lifting and aligning the device onto the antenna support structure. Furthermore, all of this must be done without damaging the delicate mirror alignments and electrical and cryogenic components attached to the cryostat.
The ALMA Front End system is the first element in a complex chain of signal receiving, conversion, processing and recording. The ALMA Front End is designed to receive signals of different frequency bands. It is far superior to any existing systems. Indeed, spin offs of the ALMA prototypes are leading to improved sensitivities in existing millimeter and submillimeter observatories around the world.
The Front End units are comprised of numerous elements, produced at different locations in Europe, North America, East Asia and Chile. The Front End installed on ACA #2 was built in North America and has four operating bands (3,6,7,9). Although it is an engineering model (not fully characterized yet), one can demonstrate for the first time the compatibility of the interfaces with the antenna and with the control software.
The Back End Antenna Articles and Amplitude Calibration Device have also been installed on ACA #2. These installations represent a subset of activities required for the full integration of the electronic systems in the antenna which enable scientific operations. “The addition of the Front End is a critical step in establishing the full signal path used by astronomical signals”, states Joseph McMullin, the AIV System Integration Lead.
Comments
jgallard@alma.cl2008-11-07 18:08:12
I was honored and pleasured to be the person in charge of the preparation and
installation for the First Production Front End for ALMA. Thanks to ALMA for
give me this opportunity.
Anonymous2009-08-10 15:22:36
The team consists the group of really professionals! It is so futurently and
interesting! Wel done! Good job!
