Mr. Niedermayer, you will work in the etit department on an international research project named “Laser Accelerators on a chip“. Can you tell us what it is about?
It is about extremely small linear accelerators. Structures of glass shall be manufactured by means of techniques known from semiconductor fabrication. The size of the structures is in the range of micrometers and lasers serve to drive them in a non-resonant manner. That’s the origin of the name “Dielectric Laser Acceleration”, DLA. Such an accelerator chip works as follows: Particles pass through the tunnel. The electric field of the incident laser is shaped by the glass in a way the particles are accelerated. Since the material can withstand high fields, the particles can be accelerated with record gradients.
What are the advantages of DLAs?
When sophisticated DLAs are available, they provide a low-cost alternative to conventional electron accelerators. Another advantage is the small size, which allows for entirely new application fields. A particular application would be an accelerator endoscope, which allows irradiating tumors from within the body.
What do you think will be the outcome of this project?
So far it was only shown that DLA works in principle. However the achieved beam intensity (particle number) is still small. In order to have an accelerator ready for practical purposes, we have to increase the intensity significantly. This requires developing focusing structures on the micrometer scale. Finally, a complete micro-accelerator shall be developed in the framework of this research project. This means a system that starts off with an electron source and delivers electrons travelling at almost the speed of light.
What is your particular task in the project?
I plan to set up a small research group working on the topic of DLA. We will simulate the electromagnetic fields and the particle dynamics in such microstructures. The goal is to determine theoretical intensity limitations for the DLA structures. A second step includes the collaboration with the partners in order to make sure that those theoretical intensity limits are also reached in the experiment.
Who are those partners you are going to collaborate with?
We will be funded by the Gordon & Betty Moore Foundation. Gordon Moore together with Andy Grove and Robert Noyce founded the Intel corporation in 1968. He is also famous for “Moore’s law“, saying that the number of transistors on a microchip doubles about every two years. The Moore Foundation funds the Stanford University directly, which redistributes the money to sub-contractors (e.g. the TU Darmstadt). We will collaborate with the Stanford University and the FAU Erlangen on the theoretical fields and the acceleration of non-relativistic electrons. The experiments on acceleration of relativistic electrons will be conducted at the Stanford Linear Accelerator Center (SLAC) in California, the Deutsches Elektronen Synchrotron (DESY) in Hamburg, and the Paul-Scherrer-Institut (PSI) in Switzerland.
How do you manage the collaboration with the international colleagues?
We plan to meet twice a year, once in Europe and once in the USA. Moreover, we will conduct video conferences regularly. Especially with the colleagues who work on simulations we plan to do video conferences monthly. In these meetings we will present results and discuss problems. However, it is likely that I have to travel to the collaborators on short notice since not everything can be clarified online.
What are the challenges in the project? What problems do you expect?
In general, this project is fundamental research. This means that in the beginning we are not yet able to estimate what results we will obtain. At the moment we cannot say if the intensity limits that we want to predict are sufficient for practical use. But I am very optimistic: perhaps there will be new applications which are tailor-made for our beam parameters.
What is your personal goal in the project?
Maybe one day we will have a cost-efficient particle accelerator for everyone, or at least at every university. Moreover, I’d be happy to encourage students to do their Master thesis in this field.