Multi-step photofragmentation studies by Auger electron – ion coincidences using high energy photons – MUSTACHE

The project aims at development of a new high-resolution instrumental setup, which will allow studying different fragmentation pathways occurring during Auger-decay cascades in molecules containing heavy atoms. Implementation of the fast Auger-electron – ion coincidence technique for hard X-ray sources is indispensable for extending the field of hard X-ray photoelectron spectroscopy to larger molecular systems, including the molecules of biological interest.
It will undoubtedly bring important scientific discoveries shedding light on the essence of hard X-ray – matter interactions.
Inclusion of heavy elements as Auger-electron emitters is in the heart of the promising new approaches to treatment of tumors, such as Auger therapy and photon activation therapy. Therefore, disentangling the underlying processes occurring during Auger-cascades and mechanisms of radiation damage generated by Auger-cascades is crucial.

The main objectives of the project are (1) to develop an advanced coincidence technique for multi-fragment momentum imaging in c incidence with fast (up to 15 keV) electrons for the studies of hard X-ray light – matter interactions; (2) to disentangle multistep fragmentation mechanisms induced by hard X-rays and explore charge transfer dynamics during Auger cascades leading to Coulomb explosion before the electronic decay is completed in benchmark molecular systems; (3) to develop experimental techniques, allowing studies of radiation damage in small biological systems, both isolated and in various environments.

Despite the ambitious nature of the project, which requires building a new setup, its risk is evaluated to be rather medium due to the outstanding expertise of the coordinator and the team in the field, which guarantees its successful accomplishment. The existence of the state-of-the-art techniques does not demand their additional extensive development but calls for their merging to boost a new area of research with tremendous potential in fundamental sciences and possible significance for health and medicine.

Construction of a new instrumental setup will require additional human resources. A postdoctoral fellow with experience in instrumental development will be hired to ensure rapid progress of the project. The choice of hiring a researcher rather than an engineer is imposed by the wealth of information typically produced by energy-selected electron – multi-fragment vector correlation imaging techniques, which requires researcher’s intuition and knowledge of the chemical physics to be able to extract the most intriguing or peculiar information on the mechanisms of photofragmentation.

The project is planned in a way that ensures deliverables at all the stages. The possible risks are evaluated, and the possible countermeasures are foreseen.

The independent thinking and leadership qualities of the project coordinator have been demonstrated through a successful management of the previous research projects. The proposed project stems from (1) coordinator’s own previous research experience, which has opened new insights of the processes involved in complex cascade decays of deep-core-hole states; (2) limitations of the existing hard X-ray spectroscopic techniques.

The previous experience of the project coordinator in development and application of coincidence and electron spectroscopy techniques provides a solid basis and prerequisites for accomplishment of the project objectives.

The fundamental, innovative and multidisciplinary character of the project perfectly fits in the frame of the ANR call.