The unique diagnostic camera FASXCAM, which can monitor X-ray radiation generated in extremely hot plasma, was developed with the support of the Technology Agency of the Czech Republic by scientists from the Institute of Plasma Physics of the Academy of Sciences of the Czech Republic in cooperation with the Nuclear Physics Department of the Czech Technical University in Prague. The new device will help researchers better control the conditions necessary for future energy production using nuclear fusion.
Nuclear fusion is considered one of the most promising sources of emission-free energy of the future. However, in order for it to take place, the fuel must be heated to temperatures reaching tens of millions of degrees. It is extremely difficult to perform reliable measurements in such an environment. Conventional electronics often fail here due to strong radiation, electromagnetic interference or extreme operating conditions.
That is why the FASXCAM camera was created. It is designed to withstand high radiation and demanding conditions inside fusion experiments. It can take up to 15 thousand frames per second and simultaneously measure the energy of the incident X-ray radiation.
It watches for impurities that can stop fusion
One of the biggest problems in the operation of tokamaks is impurities released from the reactor walls. If they get into the plasma, they can cool it and disrupt the stability of the entire experiment.
The camera allows you to monitor their occurrence in real time. Each of its 4096 pixels also functions as an independent spectrometer, so scientists obtain not only an image, but also information about the energy of the captured radiation. Thanks to this, they can, for example, detect the presence of tungsten released from the reactor walls before it significantly affects the behavior of the plasma.
“We need to monitor processes taking place in an environment where most conventional measurement systems fail. The FASXCAM camera allows us to observe events inside hot plasma with high time and energy accuracy,” says Martin Imríšek from the Institute of Plasma Physics of the Academy of Sciences of the Czech Republic.
Czech technology for European research
Detailed research results were published in the professional journal Plasma Physics and Controlled Fusion.
FASXCAM will be used in the newly built COMPASS Upgrade tokamak in Prague. Scientists also expect its possible deployment in other European facilities focused on nuclear fusion research.
The design of the camera had to solve several engineering challenges. The specially developed silicon chip must operate in a high vacuum that does not attenuate soft X-ray radiation, but at the same time must not overheat either with its own waste heat or radiation from warmer surrounding surfaces during cleaning of the vacuum chamber by burning. In order for the electronics to survive the intense fluxes of neutron and gamma radiation, key digital circuits in the chip have been doubled or tripled. Data can also be transmitted to the readout electronics using optical fibers, which eliminates the risk of electromagnetic interference and allows it to be located far beyond the radiation shielding of the experiment. This allows the electronics to function even in environments where conventional systems fail.
The development of the device is an example of how Czech teams are participating in the creation of technologies that can help in the development of safe and emission-free energy sources in the future.