KEYNOTE LECTURE

Bilge Demirköz

Director of METU-IVMER, Türkiye

Radiation environment around the Earth carries information from the Sun and other stars, such as pulsars in our galaxy and beyond. These charged-messengers at low energy are affected by the Sun’s 11-year cycle and the Earth’s geomagnetic environment (upto 10 GeV-scale). Above that, galactic cosmic rays are affected by production mechanisms in stellar environments and the propagation in the interstellar medium. The Alpha Magnetic Spectrometer on the International Space Station is a unique particle physics experiment that collects statistics since 2011 and measures charged cosmic rays upto TeV scale. AMS has published the cosmic ray flux of protons, electrons, light and heavy nuclei as well as positrons, where an excess at high energies is observed, which might hint at dark matter annihilation in the galactic halo. The METU-IVMER-AMS team analyzes positron spectrum using deep learning techniques.

This radiation environment penetrates deep into the atmosphere and the particle fluxes in the high in the stratosphere are similar to that in space. As particles enter the atmosphere and interact with air, they cause particle showers. As the multiplicity of particles increase, so does the dose rate, reaching a maximum called the Regener-Pfotzer maximum. The radiation dose rate decreases as the atmosphere gets thicker closer to ground level. Prediction of radiation dose and fault rate of electronics as well as radiation shielding and hardness assurance tests are crucial for space assets as well as high-altitude platform stations. METU-IVMER team has flown 9 balloon flights to measure radiation profiles in the stratosphere.

In this talk, I will first describe the space radiation environment, demonstrate the physics reach of AMS with published results and then show the potential of small radiation detectors for monitoring space weather and radiation in the stratosphere.

Prof. Bilge Demirköz is an astro-particle physics professor at the Ankara-based Middle East Technical University who is active in science diplomacy. She studied at MIT and Oxford for her undergraduate and graduate degrees respectively, worked at Cambridge University, IFAE Barcelona and CERN for 15 years on silicon detectors and data analysis for the ATLAS Experiment at CERN as well as the Alpha Magnetic Spectrometer (AMS) Experiment on the International Space Station. She is currently the director of the Research and Application Center for Space and Accelerating Technologies (IVMER), which performs space radiation tests as part of the RADNEXT collaboration, builds radiation detectors for the stratosphere and space and for medical facilities as well as analyze big data for space science. Her AMS research group uses deep learning to look for the tell-tale signature of dark matter in high-energy cosmic rays.
Prof. Demirköz was a Marie Curie Fellow under FP7, co-founded THE Port humanitarian hackathons at CERN and received multiple awards including the L'Oréal-UNESCO For Women in Science International Rising Talent fellowship. She served on the governing board of TUBITAK for three years and is a member of the Turkish Academy of Sciences and the Young Global Academy as well as a Young Global Leader of the World Economic Forum. Recently, she was selected to serve on the United Nations Independent Scientific Panel on AI.