02.Radiation sources in Cosmic Environment

                                                 Radiation sources in Cosmic Environment

 Radiation is defined as emission energy as electromagnetic waves or as moving subatomic particles such as moving neutrons, protons, electrons, neutrino, photons etc. Basically, radiation can divide into two types which are called ionizing radiation and non-ionizing radiation. When Ionizing radiation pass through the matter it can remove electrons from atoms, molecules including living tissues and produce ions for a example x rays, γ rays, α particles, βparticles and positrons but non ionizing radiation dos not have energy to remove electrons but have energy to molecules and sub atomic particles move in an atom but it cannot remove electrons for a examples Ultra violet radiation, Infrared radiation, microwaves, radiofrequency

Radiation can also divide into two types according to their linear energy transition ability and those are called High LET and Low LET. From above mentioned list, High LET radiation has substantial mass and charge and low LET adiation have energy in electromagnetic wave without substantial mass. High Let’s will slow down quickly and attenuated within penetrate materials but Low LETs transport way long.

Copyrights: Van Allen Belts. Image credit: NASA/Van Allen Probes/Goddard Space Flight Center

In space environment there are three radiation sources that cause to expose astronauts, satellites and space missions. Those are Galactic cosmic rays (GCR), Energetic particles trapped in Van Allen Belts and Solar activity. Galactic cosmic rays are accelerated particles release from massive stellar activities such as supernovas and these types of radiation mainly come within milky way but have possible to come from outside the milky way. Mostly 87% of galactic cosmic rays consist with energy protons and rest completed with Helium particles and high energy and high charge particles. Second type of radiation happen by incidents in earth magnetic field. Basically, earth magnetic field protect earth from other two sources of radiation but it also trapped already particles was there in toroidal regions surrounding the plant called Van Allen Belts. Third type of radiation source is particles accelerated by solar energy releases during solar flare and it include both high LETs and low LETs.

Exposing this kind of radiation directly caused for genetic mutations and cancers. In 1980 “Occupational Safety and Health Programs for Federal Employs” was identified and established Occupational Safety and Health

Administration (OSHA) and it set the radiation dose limits for space missions specially sending humans for earth orbit and beyond. And also recommended radiation protection by set up career dose limits for crew health.

In 2010 NASA developed NASA Space Cancer Risk (NSCR) model for evaluate space radiation impacts and uncertainties during space missions successfully reviewed by U.S. National Research Council (NRC) in 2012.

Next, I hope to share with you about NASA Space Cancer Risk model, Radiobiology and Human Epidemiology.

Reference: NASA Space Cancer Risk Model: 2020 Operational Implementation L. J. Chappell C. M. Milder S. R. Elgart

Stay Tuned

LinkedIn:  href="http://linkedin.com/in/sachindra-lochana-603131202" target="_blank">Sachindra Lochana