14 June 2017

MAP-Newsletter Special Edition on CALA

Dear readers,

Who isn’t fascinated by the view of the night sky? And, at the same time, as a scientist, to be driven by the desire for a deeper understanding of the connections in the birth and death of countless cosmic objects? The fundamental question here is how, following its hydrogen beginnings, the universe has been enriched with heavier elements in the course of its development.

It is not for nothing that the question of the conditions and mechanisms of the formation of heavy elements in the universe ranks among the most pressing mysteries in physics today. We already have quite clear theoretical ideas about the underlying mechanisms of the cosmic nucleosynthesis of heavy elements by fast neutron capture with subsequent beta decay (‘r-process’).

This is constantly occurring under enormous force in the universe. But the way in which the elements are actually distributed is difficult to understand under Earth-bound conditions. The understanding of this requires experimental data on atomic nuclei which we cannot yet produce experimentally.

To bring the elementary formation in the universe to light, large-scale particle accelerators are in operation – or under construction – worldwide, with costs in the billions. Their goal is to get closer to the key nuclei important to cosmic element formation in the laboratory. Atoms with the ‘magic’ neutron number of N = 126 in the nucleus are the ultimate goal.

But the problem is: on Earth, the conditions are not extreme enough. Thus isotopes with 15 neutrons less than N = 126 currently provide the most extreme limits of nuclear physics accelerator experiments. These nuclei are produced in very small quantities and only for short fractional seconds in the laboratory in order to infer their properties. Considering that a typically 10-20-fold accelerated particle flow is required to achieve a nucleus more ‘exotic’ by just one neutron, it is quickly clear that the r-process nuclei of N = 126 will not be accessible with conventional accelerator technology for a long while.

This is precisely where new possibilities with the use of laser-driven ion acceleration open up – those which will be available in the future at CALA. In addition to the focus of biomedical research, the ‘High-Field (HF) Beamline’ offers optimal conditions for entering new territory in the field of astrophysics.

The basis is a significant difference between laser-accelerated ion pulses and those of conventional accelerator systems: in laser ion acceleration, ion pulses with an unrivalled high particle density – ideally close to the density of solid bodies – can be generated, thus achieving a density many orders of magnitude higher than by conventional acceleration. Thus, a novel nuclear reaction mechanism is possible, where heavy, fissile atomic nuclei are first detached from a thin film and accelerated by means of laser light to energies above the fission barrier of approximately 7 MeV/nucleon. These nuclei then hit a second film. There, the projectile and the target nuclei alternately undergo fission. This results in light and heavy neutron-rich fission fragments, respectively. The decisive factor is that the high projectile particle density also means that the fission fragments have a high density, as a result of which a subsequent fusion, for example, between two light fission fragments, becomes possible. This reaction of two nuclei rich in neutrons now leads into the region of the extremely neutron-rich, astrophysically eminently important nuclei with 126 neutrons in their interior. There are still a number of development steps on the way to achieving this ambitious goal. But by exploiting a unique feature of laser-driven ion acceleration, we are confident that we will approach the goal of a better understanding of the formation of heavy elements in the universe.

In this issue of our newsletter, we would like to introduce you, dear readers, to many other exciting research approaches of the scientists working at CALA. We hope you enjoy reading.


Dr. Peter Thirolf

18 May 2017

The power of two million atomic power plants

At the Center for Advanced Laser Applications, physicists have constructed a new laser: the ATLAS 3000. This laser could open new avenues in medical technology.

One of the world’s most advanced high-tech laser systems has been constructed at the new Center for Advanced Laser Applications (CALA). The ATLAS 3000 delivers around 25-femtosecond-long pulses whose peak power is equivalent to the power output of multiple nuclear power plants. These light pulses could provide the basis for new directions in medical technology. They could lead medical imaging and cancer therapies into a new era. The ATLAS 3000 is being developed by Thales Optronique and the working group led by Prof. Stefan Karsch, who introduces the new laser system in this interview.

Prof. Karsch, could you outline the basic data of the new laser?

The ATLAS 3000 will provide light pulses with a peak power of 2-3 petawatts (1015 W). More specifically, once per second it releases an energy of 60 joules within about 25-30 femtoseconds. 60 joules is approximately equal to the energy required to lift a full beer stein up to a height of three meters, and 30 femtoseconds is the time is takes light to travel a distance equivalent to 1/10 of the diameter of a human hair. Thus, quite a considerable amount of energy is released in an extremely short time to achieve this high peak power.

How can we classify the power of the light pulses – how “strong” are they?

2-3 petawatts corresponds roughly to the electrical output of two million nuclear power plants (or 2 billion wind turbines). If this output were to be released continuously, it would exceed the total average power of all power plants worldwide by about a factor of 1000. For this reason, such power can be generated only by the storage and subsequent release of energy within an extremely short time. ATLAS 3000 is in the top group among similar short-pulse laser systems world-wide. The current most powerful operational laser has produced a peak power of just under 2 petawatts, while another system has demonstrated 5.5 petawatts, but practical viability has not been achieved. Additionally, several projects with 10 petawatt peak performance are planned.

What is the role of ATLAS 3000 at the CALA research facility?

ATLAS 3000 provides the central infrastructure for the majority of CALA’s goals in medical and physics research. It will supply four of five experimental beamlines with laser light, which are used to generate, study and apply laser-generated secondary radiation – that is, to produce high-energy charged particles and X-ray radiation.

What are the possible applications of these light pulses in medicine?

The main application of the CALA laser is the acceleration of charged particles (electrons and ions) by the extremely strong electric fields generated by the irradiation of plasma with intense laser light. Compared to conventional particle accelerators these fields are, depending on the exact conditions, a factor of ten thousand to ten million times stronger, which means the acceleration distances can be shortened accordingly. Furthermore, the strong fields confine the particle bunches into a much smaller source volume, which in the case of electrons is used to emit high-brilliance X-ray radiation. In this way, very compact accelerators as required by modern radiation diagnosis and therapy are possible.
With ion beams generated in that way, in the medium term radiation damage to healthy and tumor tissue by ultrashort pulses will be investigated, so that these beams can be used in the long term for irradiating tumors. Similar approaches are also pursued by e.g. the Dresden/Jena joint initiative Oncooptics. In addition to pure irradiation studies, CALA aims at the integrated approach of simultaneously using the brilliant X-ray radiation generated by the same laser for diagnostic and therapy-monitoring purposes before, after and even during tumor irradiation.

How good are the chances that this technology will be successful?

The CALA project is not without risk, but if successful, it might pave a viable route towards making current large and costly ion therapy centers more efficient and to link them with high-resolution X-ray imaging, thus making treatment accessible to more patients. Until then, we have what is certainly a long way to go, but researchers involved in CALA have made significant pioneering work and promising progress over the past decade. The scientists at CALA representing both Munich universities possess a unique knowledge base: not only in the field of the underlying physical processes in the field of high-intensity laser-matter interaction, but also in the investigation of the interaction of radiation with cells and novel imaging methods.

Interview: Thorsten Naeser

13 April 2017

At the heart of CALA

In the new Centre for Advanced Laser Applications (CALA) on the Garching Research Campus, a complex infrastructure ensures that the laser systems keep their cool.

The main entrance to the new Centre for Advanced Laser Applications (CALA) gives access to an unfussy and functional foyer decorated in green. Much of the building lies below ground level, and its elongated structure certainly cannot be mistaken for an office block. This is a research institute that employs complex instrumentation which takes up lots of space. Over the next few years, the CALA building sited at the northern end of the Garching Research Campus will become the home of some of the most advanced laser systems in the world. The primary goal of the researchers who work here is to develop laser-based sources of high-intensity, pulsed radiation specifically for medical applications.

A highly sophisticated technological infrastructure is required to ensure delivery of the best possible performance and maintenance of the stability of such advanced lasers. This was developed during the planning phase – which lasted more than 2 years – in a collaborative effort involving researchers, architects and engineers.

The core of the building is the Utilities Hall. This section houses the Center’s cooling and ventilation systems, which control the climate in the various sections of the multifunctional building. There are eight separate coolant lines, which together provide about a megawatt of cooling power. To put this in perspective, consider that a single wind-driven generator, located inland, provides between 2 and 5 MW of power. The pipelines permeate the building’s structure like a nervous system and ensure that the high-powered laser assemblies, experimental stations and laboratories never get hot under the collar.

The ventilation system was also designed in one piece to cater for the needs of all sectors of the entire research centre. In the Utilities Hall, the air-conditioning system is mounted on the ceiling and occupies a shaft that is nearly 2 m deep. Air is drawn in on the eastern side of the complex and circulates through the whole building, while the spent air is expelled on the opposite side. The system is capable of pumping 50,000 to 60,000 meters of fresh air through the interior of the Centre. In some laboratories – particularly those in which gases are used in experiments – the total volume of air is replaced eight times per hour.

In many parts of the building, the experimental halls are equipped with a raised floor, which encloses a space 1 m deep. In addition to accommodating the supply lines from the Utilities Hall to the laboratories, this tunnel system houses the laser beamline, and allows remotely generated laser beams to be guided to the appropriate stations. Some of the tiles that roof the tunnel can be removed to reveal a complex array of pipes, cables, switches and levers, through which electric current, water, fresh air, and gases such as argon, make their way to their assigned destinations.   

Then there are the so-called caves, which house special laboratories in which laser light is utilized to generate particle beams. Some of these labs are dedicated to the production of streams of protons and ions, while in others the goal is to generate X-rays. However, the physical processes involved inevitably give rise to unwanted high-energy electrons, neutrons and gamma radiation. As these energy sources are hazardous to health, researchers and technicians must be protected from their deleterious effects. This requires special shielding of these laboratories, which have double walls made of dense concrete, separated by a thick layer of compressed iron ore. This mode of construction provides efficient protection against the types of radiation mentioned above. In addition, the walls are coated with a black conductive paint. In the event of the build-up of a sudden pulse of broadband electromagnetic interference, the paint acts to dissipate the energy, just like a Faraday cage.

Five years have passed from the beginning of the planning phase in 2012 to the completion of the the new research centre. But with its carefully designed infrastructure, the building provides the ideal environment for a unique combination of laser-based instrumentation. These tools can now be used to develop new medical technologies, which will one day provide effective treatments for patients for whom no viable therapeutic options are available at the present time.

17 March 2017

Prof. Dr. Katia Parodi elected President of the DPMG

We congratulate Professor Katia Parodi on her election to the office of President of the German Society for Medical Physics (Deutsche Gesellschaft für Medizinische Physik e.V. (DPMG)) for a 2-year term with effect from January 2017. Prof. Parodi holds the Chair of Experimental Physics (Medical Physics) at LMU.

One topic of particular concern to the new DPMG President will be to stimulate greater interest in and enthusiasm for the eminently interdisciplinary field of Medical Physics among young generations. In an interview for the DGMP, Prof. Parodi answers three questions related to her own professional career and her goals during her term in office: Link zum Interview

The DGMP’s declared purpose is the advancement of knowledge through the promotion of education and research in the field of Medical Physics, which encompasses Medical Technology and the application of physics-based methodologies to medicine. Membership is open to those who are actively engaged in the area of Medical Physics, as well as individuals who are interested in furthering the development of the subject. In addition, the DPMG provides a range of further education and training programs for young researchers, which is steadily expanding.

2 March 2017

Heart examinations: Miniature particle accelerator saves on contrast agents

The most prevalent method for obtaining images of clogged coronary vessels is coronary angiography. For some patients, however, the contrast agents used in this process can cause health problems. A team at the Technical University of Munich (TUM) has now demonstrated that the required quantity of these substances can be significantly reduced if monoenergetic X-rays from a miniature particle accelerator are used.

Soft tissues such as organs and blood vessels are nearly impossible to examine in X-ray images. To detect a narrowing or other changes in coronary blood vessels, patients are therefore usually injected with an iodinated contrast agent.
These substances can sometimes be hazardous to health, however: "Particularly in patients with kidney insufficiency, complications may arise, in some cases even kidney failure," explains Dr. Daniela Münzel, , an adjunct teaching professor for radiology at TUM's Klinikum rechts der Isar. "That is why we are studying possibilities of using lower concentrations of contrast agents."

Precise X-rays

One approach to reducing the dosage has now been developed by scientists from the Department of Diagnostic and Interventional Radiology at the Klinikum rechts der Isar, working in close cooperation with the Chair of Biomedical Physics at TUM's Department of Physics. The method, which they have described in a paper published in Nature Scientific Reports, is not based on new contrast agents. Instead it relies on special X-rays generated using the Munich Compact Light Source (MuCLS), the world's first mini-synchrotron, which was officially inaugurated at TUM at the end of 2015.

"Conventional X-ray sources generate a relatively broad range of energy levels. By contrast, the energy of X-rays produced by the MuCLS can be controlled much more precisely," says physicist Elena Eggl, the first author of the paper.

Close to the absorption edge

Contrast agents such as iodine and gadolinium have an absorption edge. That means that when the substance is exposed to X-rays of a certain energy, the contrast of the final image of the marked organ is particularly good. Below the absorption edge – about 30 kiloelectron volts (keV) for iodine – the contrast deteriorates rapidly. The contrast also becomes weaker at energies far above the absorption edge.
As a result, when using conventional broad-spectrum X-ray sources, an adequate quantity of contrast agent must always be used in order to offset this effect and obtain a sufficiently sharp image for a diagnosis. The MuCLS can generate X-rays that have exactly the optimal energy level. The capability of producing such monoenergetic X-rays has existed for some time. In the past, however, this was possible only with circular particle accelerators with a diameter of several hundred meters. In contrast, the MuCLS is comparable in size to a car.

A significant improvement

The data shows that monoenergetic X-rays would make it possible to decrease the required concentration of iodine by about one third with no loss of contrast. For gadolinium, there would even be a somewhat greater reduction. A lot more research is needed, however, before real patients can be examined with monoenergetic X-rays.
"We're still at the very beginning of the development of this technology," says Elena Eggl. The MuCLS is the very first machine of its kind. Moreover, it is designed for fundamental research, and not for examining patients. But with detailed computer simulations and tests with a pig's heart, using blood vessels dyed with iodine, the researchers were able to demonstrate feasibility of the method.

Good prospects

Franz Pfeiffer, Professor of Biomedical Physics at TUM, sees the team's results as a promising start for medical research with the compact synchrotron: "The MuCLS offers numerous possibilities for medical applications that we plan to continue researching with our partners in medical fields."
The research was funded by the German Research Foundation (DFG), Munich-Centre for Advanced Photonics (MAP) cluster of excellence, the Center for Advanced Laser Applications (CALA), the Ministry for Education and Research, and the DFG Gottfried Wilhelm Leibniz Program.

Original Publication:

E. Eggl, K. Mechlem, E. Braig, S. Kulpe, M. Dierolf, B. Günther, K. Achterhold, J. Herzen, B. Gleich, E. Rummeny, P. B. Noёl, F. Pfeiffer & D. Muenzel.
Mono-Energy Coronary Angiography with a Compact Synchrotron Source 
Scientific Reports 7, Article number: 42211 (2017) doi:10.1038/srep42211

26 February 2017

Dr. Hanieh Fattahi on Minerva Fast Track Program

Dr. Hanieh Fattahi, physicist at the Laboratory for Attosecond Physics (LAP) at the Ludwig Maximilians University and the Max Planck Institute of Quantum Optics, successfully applied for the Minerva Fast Track Program. The program of the Max Planck Society promotes young female scientists, just starting their career. Fattahi gets a position for three years as well as equipment and staff in order to intensify her excellent research. 

Fattahi studied biophysics at the Sharif-University in Teheran and conducts research at the Max Planck Institute of Quantum Optics since 2008. Since 2015 she acts as group leader in the field of laser development at the Laboratory for Attosecond Physics with Prof. Krausz. 

Text: Karolina Schneider, Photo: Thorsten Naeser

3 February 2017

Virtual tour through the kingdom of ions

This 360-degree picture (keep the left button of the mouse pressed and pull) shows the experimental chamber of the team of Prof. Jörg Schreiber at the Laboratory for Extreme Photonics (Lex Photonics). Here Schreiber and his colleagues perform experiments regarding laser-driven ion acceleration. The developed prototype setups are going to move to the Centre for Advanced Laser Applications (CALA) in the coming months, we recorded them in detail before its move.

Text: Karolina Schneider, Picture: Thorsten Naeser

19 September 2016

Starting with a table

The time has come: interior work at the new Centre for Advanced Laser Applications (CALA) has begun! The first laser tables have arrived and been hoisted by crane into the hall. Even the smallest of the tables weighs around 800 kilograms; the largest about 1.2 tons. On these tables, the post-amplifier will be set up to convert the ATLAS 300 Laser into the ATLAS 3000 Laser. With a capacity of three petawatts, this will be the primary light source for the laser-driven experiments at CALA.

Text: Karolina Schneider, Pictures: Thorsten Naeser

16 February 2016

Progress on the Construction Site

Cables, shafts, pipes, lines…

Cables, shafts, pipes, lines – in these days the central nervous system of the new Centre for Advanced Laser Applications is being installed. The craftsmen are working on the installation of heating, ventilation and sanitary and cooling water facilities at the moment. Yet, the system still lies open but until March everything will have disappeared within the double floor. Then it starts and the first clean rooms are going to be set up. Then, by the beginning of next year the heart of CALA is going to beat for the first time when the lasers will be installed.

Text: Karolina Schneider, Pictures: Thorsten Naeser

22 December 2015

Letters for CALA

Within only a few days the facade of CALA has been applied and so finished the outside of the building.

The Centre for Advanced Laser Applications (CALA) was given a new face: after a year and a half of construction time the facade has been finished. Now the front of the building reads "Centre for Advanced Laser Applications" in into each other nested letters.

Christian Zeilhofer from the company Sabatrust Fassadentechnik and his colleagues had to work very carefully when painting the letters: "The challenge is to attach all the ornaments at one level and to find the correct horizontal and vertical adjustment of the letters", said Zeilhofer. The point of reference was the central axis of the CALA building.

Overall nearly nine tons of materials have been applied to the building. At first the insulation, then an eight millimeter thick reinforcement and upmost three millimeters of plaster - with the actual design of the facade. For the application the facade was especially heated, since the plaster needs a temperature of fife degrees plus to dry off. For this it was already too cold at the beginning of December. "The application of the plaster must be performed quickly, we did it with eight people within two days." Zeilhofer said.

The letters have been colored as well - the facade specialists used almost 300 liters of paint for it. With this the CALA building is now finished from the outside. And everyone who passes by can try to decipher the single letters of "Centre for Advanced Laser Applications" at the facade.

Text: Karolina Schneider, Picture: Thorsten Naeser

25 March 2015

Featured Article of Neue Züricher Zeitung

The Neue Züricher Zeitung features an article about phase-contrast X-ray imaging and CALA.

The reporter interviewed CALA-director Prof. Ferenc Krausz and prospective CALA-scientist Prof. Franz Pfeiffer.
Have a look at the online article in german.

28 October 2014

Construction of the Base Plate

Within half a day the whole base plase of CALA was constructed before the first snow fell.

Groundwork at the Garching Campus is now underway for the future site of CALA. The workers have only recently completed the ground plate of the new building, a process that started at 3am on 28th October, and lasted until 1pm that afternoon. We managed to reserve a spot and film the exciting process in time-lapse, showing the last two hours of concrete being laid in only 1.5 minutes.

23 June 2014

Start of Construction

Last summer tahe construction process of the new research facility started.

The Centre for Advanced Laser Applications (CALA), a new facility devoted to laser-based research, will soon strengthen Munich's position as a leading nexus of science and technology. The project was conceived as a collaborative venture between LMU Munich and the Technical University of Munich (TUM) in the context of the Munich-Centre for Advanced Photonics (MAP), a Cluster of Excellence. The groundwork on CALA's future site on the Garching Campus has just got underway. In the new building, located at the North end of the Campus, physicists, medical specialists and biologists plan to develop uniquely innovative laser-based technologies and explore their potential applications. CALA's primary objective is to identify new and cost-efficient approaches to the early diagnosis of cancers and other chronic illnesses, with a view to maximizing rates of cure.

Two major themes will be at the forefront of research at CALA: the development of novel biomedical imaging technologies based on high-energy X-rays, and the establishment of innovative methodologies for tumor therapy using laser-generated proton and carbonium-ion beams. CALA investigators also intend to explore the application of high-resolution infrared laser spectroscopy to the analysis of blood samples and/or respired air, which holds promise as a risk-free biomedical screening method. The approaches to be employed for the generation of high-energy X-radiation and ion beams are in principle the same. In both cases, trains of extremely short, high-intensity pulses of laser light will be used to accelerate electrons, protons or ions (electrically charged atoms) to very high velocities. Highly energetic electrons make it possible to produce X-radiation of unprecedented quality. This in turn is a prerequisite for enhanced imaging procedures that should enable tumors and other pathologies to be visualized at an earlier - and hence more tractable - stage than hitherto. By using ultrashort light flashes to accelerate protons or ions, on the other hand, the researchers hope to provide the basis for cost-efficient particle-based therapies: Since protons and ionized carbon atoms are much heavier than electrons, such beams cause much greater damage when they impinge on living tissues, and can be used to kill tumors. Thus, with the aid of laser-generated and precisely directed ion beams, targeted particle therapy could be made available to a far wider range of patients than can be treated by the current generation of particle accelerators.

In addition to medical applications, CALA will of course also focus on projects in basic research. Further studies of ultrafast processes - such as the dynamics of electrons - at atomic scales are planned. Physicists will also be exploring the interaction between light and matter using beams of a previously unattainable intensity. According to theoretical models, this capability should enable them to uncover entirely new physical phenomena.

Construction of the building itself will officially commence with the laying of the foundation stone in the spring of 2015, and is expected to be completed in 2017.

Text: Thorsten Naeser


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