ASTRON, the Netherlands institute for radio astronomy, has developed the heart for the new supercomputer for the Square Kilometre Array (SKA), the future largest and most sensitive radio telescope in the world.

Square kilometre

The Square Kilometre Array (SKA) is an new radio telescope that through international cooperation is being built in Western Australia and South Africa. In Western Australia the telescope will consist of 130,000 small antennas, divided into 512 antenna fields. The design is based on ASTRON's Low Frequency Array (LOFAR) in Drenthe. With all these antennas, SKA will generate an enormous quantity of data: one petabit per second – more than three times the world-wide internet traffic in 2018.


Gemini

ASTRON developed, together with the Australian research institute CSIRO, the heart of the supercomputer, the computer board Gemini, that will process all the data from Western Australia. Thanks to Gemini it becomes possible to combine the thousands of antennas into one large telescope, which is crucial for the astronomical research of SKA.


Enormous quantities of data

Gemini is a computer board with the latest Xilinx processor (a Field Programmable Gate Array, FPGA). With this, the Gemini can process enormous quantities of data continuously. To process and combine all the data streams from the SKA in Australia, ultimately a supercomputer will be built that contains a total of 288 Gemini boards. After combining each antenna field, the supercomputer has to process a total of 5.8 terabits per seconds of data. That is why boards with efficient processors are essential. As a comparison: the Amsterdam Internet Exchange, the largest internet node in the Netherlands, has an average data rate at the entrance of 3.4 terabits per second.


Water cooling

Gemini requires a lot of energy, which is converted into heat. For the optimal cooling of the processor, ASTRON developed a special water block. The water carries the heat from the processor directly deep underground in the Australian desert. This allows the processor to be cooled much better than traditional air cooling. An additional advantage is that a cooler processor uses less energy.


Large production

For the production of the 288 Gemini-boards ASTRON works closely with Neways Electronics in Leeuwarden. Thanks to this partnership the board, despite its great complexity, can be produced in large numbers. The programming of the specialised processor will take place in a collaboration between the CSIRO and the Auckland University of Technology in New Zealand.