Ionizing and non ionizing radiation.pptx

ionizing and non ionizing radiation

1. IONIZING AND NON IONIZING RADIATION BHADRA A NAIR MSC MICROBIOLOGY

2. ELECTROMAGNETIC SPECTRUM

3. Electromagnetic RADIATION Electromagnetic radiation refers to the emission and propagation of energy through space or a material medium. Broadly classified into two categories: Ionizing Radiation : Has enough energy to remove electrons from atoms. Non-Ionizing Radiation : Insufficient energy to ionize but can excite molecules and atoms.

4. Non ionizing radiation Electromagnetic radiation that does not carry enough photon energy to ionize atoms or molecules Interacts with matter mainly by causing excitation, vibration, or heating effects. Photon energy is less than 12.4 eV Longer wavelength( >100nm) Lower frequency

5. Ultraviolet radiation (UVR) Electromagnetic radiation with wavelengths between 100–400 nm. Energy Range: 3 –12.4 eV Types of UV Radiation : UVA (315–400 nm): Deep skin penetration, aging, oxidative stress UVB (280–315 nm): Sunburn, DNA mutations, skin cancers UVC (100–280 nm): Absorbed by ozone; germicidal use at ~ 260nm Sources : Natural: Primarily from the sun. Artificial: UV lamps, tanning beds, welding arcs, and lasers.

6. Biological Impact of UV Radiation Mechanism of Damage : UV radiation excites molecules, breaking chemical bonds without ionization. Forms pyrimidine dimers in DNA, leading to mutations. Health Effects : Skin: Sunburn, premature aging, increased risk of skin cancer. Eyes: Photokeratitis, cataracts, retinal damage. Immune system : Supress cell mediated immunity Protective Measures : S unscreen, UV-blocking sunglasses protective clothing limiting exposure during peak sunlight hours.

7. Applications : Medical and research : Phototherapy for skin disorders like psoriasis, vitiligo Studying DNA repair mechanisms Vitamin D synthesis support Sterilization of medical tools Industrial and Commercial Uses : UV curing for polymerizing coatings or adhesives in medical device manufacturing. Used in forensic science to detect biological traces under UV light. Environmental and Analytical Applications : UV spectroscopy analyzes biomolecules by measuring absorbance at specific wavelengths. Monitors atmospheric ozone levels Water & air disinfection using UVC germicidal lamps Fluorescence and Imaging : UV light excites fluorescent dyes in microscopy Used in gel electrophoresis to detect DNA/RNA stained with UV-sensitive dyes

8. Visible light Wavelength range : ~400–750 nm Energy range : ~1.65–3.1 eV Position in spectrum : Between ultraviolet (UV) and infrared (IR). Positive roles Enables vision - rods & cones absorb different wavelengths. Essential for photosynthesis in plants. Excessive Exposure Blue light hazard: prolonged exposure damages retinal cells. Eye strain and sleep disruption from artificial lighting/screens. Intense visible light (e .g., lasers, welding arcs) cause retinal damage . Biological Effects

9. Applications Medical : Phototherapy for neonatal jaundice Ophthalmic surgeries using lasers Diagnostic tools (endoscopy, microscopy). Industrial and Technological : Optical communication (fiber optics) Imaging and microscopy in research Laser cutting, welding, and precision engineering UV – Visible spectroscopy for drug analysis UV – Visible Spectroscopy Fibre optics

10. Infrared radiation Wavelength range : ~700 nm – 1 mm Energy range : ~0.001–1.7 eV Subdivisions : Near IR (770 –1400 nm) – closest to visible, used in sensors. Mid IR (1.4 – 3 μm ) – vibrational spectroscopy. Far IR (3 μm –1 mm) – thermal radiation, heat sensing. Infrared absorption heating of tissue by increasing molecular vibrational activity Sources Natural : Sun, Geothermal activity , human body , fire Artificial : Incandescent bulbs, IR lamps , heaters, lasers , remote controls.

11. Biological Impacts : Thermal therapy : IR lamps used to relieve muscle/joint pain Wound healing : Low-level IR promotes tissue repair Skin : prolonged exposure to intense IR can lead to burns Eyes : cataracts from occupational IR (e.g., glassblowers cataract) , corneal burns Cellular Effects : Heat stress can alter protein function or induce heat shock responses. . Applications Thermal Imaging : IR cameras detect temperature differences –Used in surveillance , medical imaging Night vision : IR goggles enhance visibility in low light environment, Security camera Neuroscience : Near-IR in optogenetics , fNIRS monitors brain activity non-invasively .

12. Medical : IR thermography for fever & circulation studies IR Spectroscopy : Analyses biomolecule structures (e.g., proteins, lipids) by measuring vibrational transitions. Communication : En ables short-range wireless communication in devices like remote controls, Environmental Monitoring : Measures IR emissions to study greenhouse gases or heat loss in ecological systems Astronomy : IR telescopes for studying stars and cosmic dust James webb Telescope

13. Microwaves Wavelength range – 1mm – 1m Frequency - 300MHz – 300 M Hz Energy range - ~10⁻⁵ – 10⁻³ eV Position in Spectrum : Between infrared and radio waves SUBDIVISIONS On the basis of frequency L-band (1–2 GHz) S-band (2–4 GHz) C-band (4–8 GHz) X-band (8–12 GHz) Ku/K-band (>12 GHz) Sources Natural : Cosmic microwave background , atmospheric emissions, Sun .Artificial: Microwave ovens, radar systems, satellites, Wi-Fi routers, cell towers, Bluetooth devices.

14. Interaction with matter Microwaves heat materials by making polar molecules primarily water, rapidly rotate in response to the changing electric field. This constant rotation creates internal friction between excited molecules, which converts microwave energy into thermal energy. Applications Microwave oven for baking Radar System Wireless Networks - Wifi , Bluetooth Satellite commu nic ation and Telecommunication Global positioning System (GPS) Remote sensing Microwave ablation for cancer treatment

15. RADIOWAVES Wavelength : 1 m – 100 km Frequenc y: 3 kHz – 300 GHz Energy : <10⁻⁶ eV Position in Spectrum : Lowest energy end of EM spectrum, below microwaves. Types (based on frequency) Very Low Frequency ( 3–30 kHz) : Submarine communication. Low Frequency (30–300 kHz ): Ground wave propagation Medium Frequency (300–3000 kHz): AM radio High Frequency (3–30 MHz) : Shortwave radio , Skywave for long distance Very High Frequency (30–300 MHz) : FM radio, TV. Ultra High Frequency (300–3000 MHz) : Mobile phones, TV.

16. Source Natural : Lightning discharges , Solar flares , Cosmic radio waves Artificial : Radio , TV transmitters , Cell towers Applications Communication Radio Broadcasting: AM and FM radio transmit audio signals to listeners.
Satellite Communication: Radiowaves transmit signals between Earth and satellites, facilitating global communication. Navigation GPS (Global Positioning System) : determine precise locations and provide navigation services.
- Radar Systems: Detect and track objects, used in air traffic control and weather forecasting. Medical MRI (Magnetic Resonance Imaging): Create detailed images of internal structures.
Diathermy: Radiowaves heat tissues, relieving pain and promoting healing. Scientific Research NMR Spectroscopy: Radiowaves analyze molecular structures and properties.
Remote Sensing: Radiowaves monitor environmental changes, like soil moisture and ocean currents.

17. IONIZING RADIATION Type of radiation that carries enough energy to remove tightly bound electrons from atoms or molecules, thereby producing ions. Exist in the form of particles or electromagnetic waves. Radiation - X Rays , Gamma rays Particles – Alpha particles, Beta particles ,Neutrons Ionization potential :The minimum amount of energy needed to remove the outermost electron from an isolated gaseous atom, forming a positively charged ion .

18. Effects of Ionizing Radiation Direct Effect : Radiation deposits energy directly in biological molecules and causes molecular damage . More significant for alpha particles and neutrons DNA strand breaks protein denaturation Lipid peroxidation Indirect Effect : Radiation interacts with water, producing ROS (OH, H2O2, O2·-) .Radicals attack and cause oxidative damage to biological molecules like DNA, proteins, lipids. Predominant in radiations such as X-rays and gamma rays. Radiation effects depend on dose , dose rate and radiation type

19. X-RAY Discovered by Roentgen in 1895 Wavelength: 0.01 – 10 nm Frequency: 3×10¹⁶ – 3×10¹⁹ Hz Energy: 100 eV – 100 keV Overlap with gamma rays Sources Natural: Cosmic X-rays. Artificial: X-ray tubes (accelerated electrons hitting metal targets).

20. Application Medical Applications Diagnostic Imaging: to produce images of internal structures, helping diagnose fractures, tumors, and diseases like pneumonia.
Computed Tomography (CT) Scans: X-rays create detailed cross-sectional images of the body. Industrial Applications Non-Destructive Testing (NDT): X-rays inspect welds, castings, and composites for defects.
Security Screening: X-ray machines scan luggage and cargo for prohibited items.
Material Analysis:X-ray fluorescence (XRF) determines elemental composition. Scientific Applications Crystallography: X-rays determine the structure of crystals and molecules.
X-ray Astronomy: X-ray telescopes study high-energy celestial phenomena.
Elemental Analysis: X-rays analyze the composition of materials.

Other Applications Food Inspection: X-rays detect foreign objects and contaminants.
Forensic Science: X-rays analyze evidence, such as bones or bullets.

21. Gamma radiation γ-rays is a highly energy electromagnetic radiation emitted from the nucleus of radioactive atom (cobalt-60 or cesium-137) during radioactive decay. Shortest wavelength and highest frequency Energy: Very high — typically above 100 keV. Extremely high penetration power having no mass and charge Dense material such as lead or concrete to shield against penetration After alpha decay or beta decay, the daughter nucleus is often left in an excited (unstable) energy state. To become stable, the nucleus releases the excess energy in the form of a gamma photon (γ-ray). Sources Natural : Cosmic radiation ,radioactive minearals Artificial : Nuclear reactors , Radiation therapy

22. APPLICATIONS Sterilization of medical equipment like gloves syringes and heat sensitive materials Food irradiation for preservation and prevent spoilage Gamma rays used to kill cancer cells in radiation therapy (Co- 60 and Cs-137) Medical imaging such as PET scans , Gamma camera scans to visualize organ function Nuclear medicine : radioactive tracers emit gamma radiation (Technetium-99m) Radiation Gauging Used to measure material thickness or density (in paper, plastic, or metal industries) Gamma radiation is involved in the operation and development of nuclear reactors and weapons.   Crop mutation breeding to develop improved crop varieties

23. ALPHA PARTICLE Alpha decay is a radioactive process in which a particle with two neutrons and two protons is ejected from the nucleus of a radioactive atom. The particle is identical to the nucleus of a helium atom. Alpha decay only occurs in very heavy elements such as uranium, thorium and radium. Penetration power is very low and can be shielded by paper or skin layer Strongly ionising and internal exposure can cause accumulation in tissues of bone , kidney, liver , lung causing local damage. \ Discoveere

24. Beta particles Beta decay is a type of radioactive decay in which an unstable nucleus emits a beta particle (electron or positron) to become more stable. In β⁻ decay, a neutron transforms into a proton, emitting an electron and an antineutrino; in β⁺ decay, a proton transforms into a neutron, emitting a positron and a neutrino. Penetrating power is moderate. They can pass through a few millimeters of living tissue and are typically stopped by a thin sheet of aluminum or plastic Beta particles have moderate ionizing power - Weaker than alpha particles, but stronger than gamma rays.

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