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August 24, 2021
Astronaut Thomas Pesquet has activated Lumina, an optical fibre-based dosimetry experiment on board the International Space Station
Image above: Lumina is an optical fibre-based dosimetry experiment developed by CNES, iXBlue, UJM and CERN (Image credit: iXblue/CNES/G. Le Bras).
In a spacecraft, in order to protect both crew and electronics from radiation, it is mandatory to invest in effective radiation monitoring systems. The International Space Station (ISS), just like the Large Hadron Collider at CERN, is a complex radiation environment that requires bespoke dosimetry devices. Optical-fibre-based technologies can provide both distributed and point radiation dose measurements with high precision.
On 18 August, ESA astronaut Thomas Pesquet activated the Lumina experiment inside the ISS as part of the ALPHA mission. Developed under the coordination of the French Space Agency, CNES, and with the involvement of CERN, the Laboratoire Hubert Curien at the Université Jean-Monnet-Saint-Étienne, and iXblue, this project uses two several-kilometre-long optical fibres as active dosimeters to measure ionising radiation in the ISS with very high sensitivity.
Image above: ESA astronaut Thomas Pesquet installing the Lumina experiment inside the Colombus science laboratory of the International Space Station (Image credit: CNES).
Daniel Ricci, leader of the Fibre Optics section of the Engineering department at CERN, explains: “When exposed to the space radiative environment, the optical fibres experience a partial loss of transmitted power, which we call radiation-induced attenuation.” Diego Di Francesca, fibre-dosimetry project leader in the team, describes in detail how the dosimeter works: “Using a reference control channel, the radiation-induced attenuation of some special optical fibres can be accurately measured and put in relation with the total ionising dose. The sensitivity of the device is mostly governed by the length of the fibre. Depending on the dosimeter design, the longer the optical fibre dosimeter, the more sensitive it is.”
In order to prevent radiation-induced damage to the electronics inside the accelerators, CERN has been working with radiation sensors based on optical fibres for six years. Building on this experience, CERN has made a technical contribution to Lumina by helping with the theoretical analysis of the optimised architecture of the dosimeters and by carrying out the low- and high-dose irradiation tests needed to calibrate the instrument. Once the experiment is fully installed by Thomas Pesquet, CERN will also contribute to the analysis of the experiment’s ground and flight data during its one to five years of operation.
Image above: Calibration tests of the Lumina dosimeter in the irradiation facilities at CERN (Image: CERN).
“A challenge of Lumina is to be sensitive enough to measure low radiation rate variations, considering the shielding provided by the ISS shell. The calibration performed at CERN, on a ground reference model, will enable us to post-process the measurements and will lead to accurate results,” explains Florence Clément, project manager of the Lumina experiment at CNES/CADMOS. “We are convinced that the ISS is only a first step for fibre-optic dosimeters as we venture further into space. As we move away from Earth, the radiation levels increase, and so does the need for reliable dose monitoring.”
By contributing to this experiment, CERN continues to demonstrate its added value for the space sector. “This joint experience in space is an important result of the framework collaboration agreement established between CERN and CNES a few years ago, with special focus on radiation issues,” highlights Enrico Chesta, Aerospace Applications Coordinator in CERN’s Knowledge Transfer group. “To monitor radiation damage to electronics, CERN has developed instruments that can also be used on satellites. In the field of irradiation testing, our unique technical facilities are able to reproduce a variety of environments representative of the most extreme radiation space conditions.”
Find out more about CERN’s impact on aerospace: https://kt.cern/aerospace
Note:
CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.
The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.
Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.
Related links:
ALPHA mission: https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Alpha
CERN Engineering department: https://home.cern/about/who-we-are/our-governance
For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/
Images (mentioned), Text, Credits: CERN/By Antoine Le Gall.
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