Seminars and Colloquia

August 22, 2019
155 Physical Sciences II, HEP Meeting Room

Electroweak baryogenesis, experimental status, progress and extensions

Dr. Graham White, TRIUMF



August 20, 2019
147 Physical Sciences II

Downfall from heaven: Unique carbon nanomaterials from superbolide impacts from North-East Russia

Prof. Pavel Avramov, Kyungpook National University, Republic of Korea

Unique physical properties and atomic structure of real impact diamonds from Popigai astrobleme (Yakutia, North-East Russia) and exotic closed-shell multiply twinned graphite microcrystals found in Chelyabinsk superbolide dust (Feb 15, 2013, Ural mountains, Northern Russia) were studied using ab initio DFT and MD simulations. The key features of unique atomic structure and mechanical properties of the carbon nano- and microcrystals extracted from real impact and meteorite materials were interpreted using electronic structure calculations. The unique scale and dramatic consequences of both historic events for dinosaur existence and human history makes a theoretical consideration of the carbon nanostructures critically important for survival of entire humanity.

July 18, 2019
110 Physical Sciences

The Ionizing Radiation Environment for Human Space Flight: Risks and Mitigations

Dr. Ramona Gaza, NASA/HH&P Radiation SME and MARE Science Lead, Leidos, Houston, Texas
Dr. Razvan Gaza, Orion Radiation SME and MARE Project Manager, Lockheed Martin Space, Bethesda, Maryland

Space is a harsh environment for human explorers. Ionizing radiation occurs naturally in space, and can have detrimental effects on both the spacecraft hardware and the health of the astronaut crew.

This presentation provides an overview of the space ionizing radiation environment, NASA radiation measurements and instrumentation, models and tools used for radiation exposure predictions, space weather forecasting needs for long duration exploration missions, and exposure risks and mitigation with a focus on crew health. The particularities are discussed of the environmental components and the implications on risk assessments and spacecraft shielding efficiency.

NASA’s Exploration Program aims to return astronauts to the Moon by 2024. The Orion spacecraft is the first Exploration architecture element, and the first NASA human spacecraft to include design requirements for crew radiation protection. Orion is designed by Lockheed Martin as prime contractor. Its maiden flight Exploration Flight Test 1 (EFT-1) was successfully completed in 2014. The trajectory exposed the spacecraft to the core of the Van Allen proton belts. This provided an opportunity for validating the radiation shielding predictions by measurements. The results indicated good correlation with pre-flight predictions. Orion’s next test flight Artemis 1, formerly known as Exploration Mission 1 (EM-1) is scheduled for 2020. The 21-42 day mission to cis-lunar space provided the opportunity for a large scale international radiation experiment referred to as the Matroshka AstroRad Radiation Experiment (MARE). MARE consists of two radiotherapy phantoms—named Zohar and Helga—located in the Orion seats #3 and #4, and fitted with an extensive complement of passive and active radiation detectors. Zohar is also fitted with AstroRad—a novel individual astronaut radiation shield manufactured by StemRad Israel. This allows simultaneous characterization of the intravehicular radiation environment and mitigation efficiency. NASA, the German Aerospace Center DLR, and the Israeli Space Agency ISA are the co-principal investigators to MARE. The co-investigator team consists of dosimeter providers from 10 countries on 3 continents, and includes the Department of Physics at OSU. Lockheed Martin facilitates MARE by as payload integrator and liaison to the Orion Program on behalf of the international science team.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.