The most powerful laser in the world, Extreme Light Infrastructure – Nuclear Physics (ELI-NP), is being built in a research facility near Bucharest in Romania. It is expected to have a impact on medicine, isotope production and security systems.
“A game changer for 21st Century science” as prof. Toshiki Tajima described it, is going to be the most advanced research facility in the world focusing on photonuclear physics and its applications. ELI-NP represents Nuclear Photonics, an emerging brand new discipline to explore and control nuclei by photons. The infrastructure’s two main components are a high intensity laser system and large energy gamma beams, two elements of extreme light. Chargeless gamma particles can be precisely resonated with the internal structure of the nucleus, if the energy of the gamma is chosen appropriately. With the large amplitude laser, the researchers may be able to excite and/or break up the nucleus of an element.
ELI-NP is planned to deliver light with the power of 2×10 petawatts (the measurement unit for power, 1 PW = a million billion watts) once operational, while the other laser systems currently provide about 1 PW. This means that it will have almost 10% of the power that the Earth receives from the Sun.
“It is an extremely short pulse. When focusing such a laser beam on a target, extremely intense electromagnetic fields are obtained and a number of new and very interesting phenomena result, such as ionization, plasma creation, particle acceleration or even new particles are created by quantum effects” says Florin Negoita, researcher at ELI NP.
Such properties could pave the way to many innovations in particle acceleration with possible future applications in medicine, especially in the therapies against cancer. Proton therapy is a type of particle therapy that uses a beam of protons (ionizing radiation), to the irradiate diseased tissue. The chief advantage of proton therapy over other types of external beam radiotherapy is that the large doses of protons go deep into the tissue, sparing the surrounding tissue. Protons represent the radiation sent by a special medical device to the respective tumor in order to kill it. They are currently produced by the large particle accelerators, at extremely high costs. For example the total cost, including the technology investment for a recently built particle accelerator in Cracow; which is producing this type of proton; for in excess of 60 million euros. The ELI-NP scientists intend to generate protons by the laser, at a much lower cost.
“Proton irradiation experiments mean the formation of the proton beams, that perform a cell culture irradiation. We have the opportunity to do such initial irradiation experiments here to see the effects of the proton beam on the cell cultures, at the genetic level. We will have a small biology lab where we will be able to maintain these cells” explains Bogdan Diaconescu, researcher at ELI-NP.
Another promising application of this laser system is the production of radioactive isotopes for the medical imaging. This time it is not intended to kill the diseased cells, but finding and the visualization of the cancer cells. One can also see and understand, through imaging other functions of the human body. Besides the high power laser, ELI-NP is developing a gamma beam system, able to produce these type of isotopes. Gamma beam uses other laser systems, less powerful, but equally preformat, to generate brilliant gamma ray. The radio isotopes produced by the gamma beam would fill the needs of an increasingly demanding market looking for alternatives, as the main isotopes manufacturers are a few particular reactors around the world which are getting old.
“When one of these reactors goes into maintenance or shuts down, there are many imbalances on the market. Actually, the demand exceeds the production. We believe that gamma beam system will be able to produce them competitively”, says Florin Negoita.
Gamma beams release such a penetrant radiation that it can go through some materials and could identify the content of specific objects, without the need to open them up. It is the case of the huge containers or tanks transported by boats or planes, whose thorough control is nowadays not really possible. A new laser based technology could be developed to help the guardians of port and airports to see inside the boxes and discover possible dangerous merchandise. On the same path of the security are other applications, which could allow to look inside fast moving objects, such as the aircrafts’ motors while they are running.
“The lasers have the property to generate particles within very short pulses which enables people to see very fast phenomena. We expect the gamma radiations to be intense and short enough, that we could take a frozen picture of a fast moving object, let’s say inside of a container, in one single laser burst, and then, at the next pulse, you could see what happened after it had turned. Further applied developments of multiple particle beams could be the investigation of material aging in a high nuclear dose environment” explains Negotia.
The high power laser in Romania is now partially operational, some tests are already undergoing using several parts of it, whilst other parts are still being installed. It will reach its greatest potential, by a projected 2019. The research facility is planned to cover frontier fundamental physics, new nuclear physics and astrophysics, as well as applications in nuclear materials management, materials science and life sciences. Several laboratories will support further tests in fields such as: optics, electronics, biology.
ELI-NP is one of the four pillars of a larger cooperation initiative supported by the European Union. Other parts include High Energy Beam Sciences in the Czech Republic and Attosecond Laser Science in Hungary. They are three specialized, coordinated and complementary facilities, each of them being planned to rely on cutting-edge laser systems, optimized for their specific scientific purpose. A forth pillar, Ultra High Field Science, is envisaged to be built, but the location has not yet been decided.