My Research Directions
The discovery of the nucleus in the center of the atom by Rutherford in 1911 laid the foundation of a new, modern research field: Nuclear Physics. Nuclear Physics has dominated modern science for several decades and continues to offer groundbreaking phenomena and novel aspects of the microcosmos.
A century later, Nuclear Physics is going through a second flourishing season. The technological evolution of the nuclear techniques is based on the development of unstable (radioactive) beams in large facilities. The radioactive beams (RIB) have broadly expanded the limits of the nuclear chart we can investigate and look for new phenomena at hard-to-reach corners. During the last 10-15 years, RIB stand at the forefront of nuclear science and provide the scientific means to discover new phenomena and nuclear properties, test theories and reach the extremes of nuclear matter.
At the same time, stable-beam facilities are upgraded and provide the instruments to search for the building blocks of our universe, investigate the birth of stars and galaxies and understand cosmic energy production, while playing an important role in educating the new generations of nuclear scientists.
At the center of all these research initiatives resides the effort to understand the behavior of the nuclear building blocks, i.e. the proton and neutron, at extreme states of matter. The valley of stability has attracted lots of attention in the past, but still provides a plethora of information, especially due to studies of proton-neutron interaction.
A very important tool in these scientific endeavors are the electromagnetic properties of nuclei, such as the magnetic dipole and the electric quadrupole moment. EM moments offer unique information on the shape, the excitation modes, the type of vibration or rotation, the collectivity or the competition between protons and neutrons in a nucleus. Both ground and excited states in nuclei may be studied in terms of their electromagnetic properties to obtain knowledge of the quantum wave functions.
A recent example of such studies is the measurement of the magnetic dipole moment in the neutron-rich aluminum isotopes (31-34Al). The aim of the experimental investigation was to approach the recently discovered “island of inversion” from the “east” of the nuclear chart. The analysis of the experimental data is on the way and the prelimary results shed light on the wavefunctions of the states in these isotopes that lie close to shell closure at N=20.
nuclear reactions & astrophysics
Nuclear reactions are the main way to access all nuclear systems in an attempt to study their roperties. Regardless if we are searching for the nuclear stucture or study the evolution of a reaction network in a systematic fashion, reactions stand at the center of our investigations.
Nuclear reaction studies provide critical information on astrophysics-related issues. The combined field, Nuclear Astrophysics has attracted lots of attention in the recent years, developing a new scientific filed within Nuclear Physics. Main questions posed by nuclear astrophysics are the understanding of the creation and destruction of stars and galaxies, the fuel “burning” network at the center of stars and cosmological questions approached by questions on nuclear reaction occurring in these systems.
On the other hand, spin polarization properties or the optical potential in projectile-target systems, as well as the role of isospin in extreme nuclear conditions are investigated in nuclear reactions, both experimentally and theoretically.
Recent examples of such activities are the investigation of spin polarization at mirror nuclei, the nuclear structure with (p,γ) and (p,p’γ) reactions and the application of nuclear reactions (e.g. RBS spectrometry etc).
applications of ion beams and radiation
Besides fundamental knowledge gained by the studies of nuclear structure and reactions, Nuclear Physics has been proven useful in everyday’s questions and practicalities. There are several synergies between Nuclear Physics and other scientific fields, such as Medicine or Environmental Science.
Several types of radiation are produced in nuclear systems, such as γ and X, which are fundamental in extracting information from materials and about processes in several scientific fields, such as Environmental Science, Geology and Geochemistry, Material Science, Electronics, Biology etc. In addition, an immediate consequence of Nuclear Physics is Health and Medical Physics with a large impact to general population on both diagnosis and disease treatment.
On the other hand, synchrotron radiation is one of the modern tools that utilize radiation to study environmental samples, radiological and chemical contamination, as well as impact on the general population. Recent experimental studies at ANKA center in Germany have focused on radiochemical impact of isotopic thorium in environmental samples and the dispersion of toxic heavy metals in greek soil, mainly due to Saharan dust deposition. These studies are now expanded to explore the full cycle of radiative samples in the greek environment and its impact to citizens.
Very recently, the NUSTRAP group have invested a great mount of effort to expand investigations in the environments by both in situ and offline analysis of NORM and TENORM radiation. A new NaI-based mobile spectrometer has been optimized, characterized and deployed in the research field. Additionally, a 25% HPGe detector has been recently donated to the group and is currently being prepared (calibration, simulation) to expand the limits of our scientific program by developing a gamma-spectroscopy station.