PhD thesis award of the Association of the Friends and Sponsors of DESY

Chairman of the Association of the Friends and Sponsors of DESY, Friedrich-Wilhelm Büßer, congratulates this year´s prize winners Ulrike Frühling and Christoph Weniger.

The PhD thesis award 2010 of the Association of the Friends and Sponsors of DESY is distributed equally to Dr. Ulrike Frühling (DESY and University of Hamburg) for her thesis titled "Light field driven streak-camera for single-shot measurements of the temporal profile of XUV-pulses from a free-electron laser" and to Dr. Christoph Weniger (DESY and University of Hamburg) for his thesis titled “From SuperWIMPs to Decaying Dark Matter: Models, Bounds and Indirect Searches“. The Association presents this prize to award outstanding PhD thesis that were concluded in the period of 1 January 2009 to 31 March 2010.

Ulrike Frühling, born 1980 in Hamburg, began to study physics in 1999 at the Albert-Ludwigs-University in Freiburg. After her intermediate diploma in 2001, she went to the University of Melbourne in Australia for one year. In 2005, she obtained her diploma degree in the field of ion and molecular physics in Freiburg. Then she was granted a DESY scholarship and as a graduate student at DESY she worked at the free-electron laser FLASH. In 2009, she earned her doctoral degree from the University of Hamburg.

Within the scope of her thesis, Ulrike Frühling developed a new light field (THz range) driven streak camera to measure the time structure of single extremely ultraviolet (XUV) pulses at the free-electron laser (FEL). The FEL generates highly intensive ultra short XUV light pulses with a pulse length of only a few femtoseconds. The stochastic nature of the method used to produce radiation – the self amplifying spontaneous emission (SASE) – leads to enormous fluctuations in the length and time structure of the XUV pulses at each shot. With conventional streak cameras, it is only possible to obtain resolutions of some hundred femtoseconds. The new camera allows measurements down to the attosecond range and it will be an important instrument for future measurements at the free-electron laser.

Christoph Weniger, born 1980 in Wuppertal, began to study physics in 2000 at Bonn University where he obtained his diploma degree with distinction in 2006, with a thesis in theoretical physics in the field of condensed matter. Then he was granted a DESY scholarship, and in the DESY theory group he graduated and earned his doctoral degree from the University of Hamburg.

The PhD thesis of Christoph Weniger deals with the nature of dark matter. It is about the so-called WIMPs (Weakly Interacting Massive Particles) as possible candidates of dark matter. These have a very weak interaction with the particles of the standard model. The decay of these particles could influence the fusion of the first elements in the early universe. Alternatively, their decay products could leave traces in cosmic radiation. His thesis especially investigates the influence of decaying dark matter on cosmic radiation in a model-independent way. In the past years a number of anomalies had been identified in positron and gamma spectra. The thesis is an important contribution to understand these signatures; their origin is a topic of current research.