Gamma ray spectroscopy

Analytical biochemistry

1. -BY ARYA RESON I MSC BIOCHEMISTRY Bharathiar University ANALYTICAL BIOCHEMISTRY GAMMA RAY SPECTROSCOPY

2. CONTENTS GAMMA RAYS GAMMA RAY SPECTROSCOPY WORKING PRINCIPLE COMPONENTS OF GAMMA RAY SPECTROSCOPY ADVANTAGES & DISADVANTAGES APPLICATIONS REFERENCES

3. GAMMA RAYS Gamma rays ( symbol ‘ γ ’) are a type of electromagnetic radiation that arising from the radioactive decay of atomic nuclei. It is also known as gamma radiation. It imparts hightest photon energy , the shortest wavelenght of electromagnetic waves and have f requencies greater than about 3×10 19  Hz .

4. HISTORY OF DISCOVERY T he gamma radiation is one of the three types of natural radioactivity discovered by B ecquerel in 1896 . In 1900 , Paul Villard , a French chemist and physicist, discovered gamma radiation . In 1903 , E rnst Rutherford named this radiation gamma rays based on their relatively strong penetration of matter. SOURCES OF GAMMA RAYS On Earth , gamma rays orginated as a result of radioactive decay , from atmospheric interactions with cosmic ray particles. Also from nuclear explosions , lightning , neutron stars and pulsars , supernova explosions, and regions around black holes. Due to its high penetration power, its hazardous to life. Gamma rays are waves , they have no mass and charge.

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6. GAMMA RAY SPECTROSCOPY Gamma ray spectroscopy is the qualitative a nalytical technique that can used to identify various radio nuclides ,and radioactive isotopes in a sample. G amma ray spectrometer   is a  device  used for measuring the energy distribution of gamma radiation. Gamma rays are produced in various energies and intensities that are detected and analyzed with spectroscopy system , a gamma ray energy spectrum is produced.

7. WORKING PRINCIPLE G amma-ray spectroscopy works by measuring the energy of incoming gamma rays using a detector. The initial stage in gamma-ray spectroscopy is to detect gamma rays using an appropriate detector . The detector captures and measures the energy of incoming gamma rays. Scintillation detectors, semiconductor detectors, and gas-filled detectors are among the detectors used in gamma-ray spectroscopy. The energy of the incoming gamma rays is converted into electrical signals that may be processed and studied by these detectors. The spectroscopic system measures and records the energy of gamma rays when they are detected. The derived energy spectrum depicts the distribution of gamma-ray intensity as a function of energy. The spectrum is a visual depiction of the various energy levels found in gamma-ray emissions. The observed energy levels are compared to the known energies associated with various gamma rays emitted by radioisotopes to identify the identification of the gamma-ray emitter.

8. COMPONENTS OF GAMMA RAY SPECRTROSCOPY The most basic components are 1. Detector ( High voltage power supply ) 2. Multichannel analyzer (MCA) Additional components may include  signal amplifiers , rate meters, peak position stabilizers and data handling devices .

9. PHOTOELECTRIC EFFECT The most common way for low energy photons to interact with matter. The photon disappears after the i nteraction. COMPTON EFFECT The second most way for gamma photon with mid energies to interact with matter. The wavelength of the scattered photon is higher than that of incident photon. PAIR PRODUCTION EFFECT The production of a pair of mutual antiparticles ,an electron and a positron. It occurs mainly with more energetic gamma produced by accelerators or found in cosmic rays.

10. DETECTORS Gamma spectroscopy detectors are passive materials that are able to interact with incoming gamma rays. The most important interaction mechanisms are the photoelectric effect, the Compton effect and pair production  . Though this processes, the energy of the gamma ray is absorbed and converted into a voltage   signal by detecting the energy difference before and after the interaction. The most commonly used detectors are Sodium Iodide [NaI] , High Purity Germanium [ HPGe]. A pulse is produced for each gamma ray interacting in the detector. The greater the energy deposited in the detector , the larger the pulse. The HPGe is easily the best. Scintillation detectors The thallium – activated sodium iodide detector or NaI (TI) detector , responds to the gamma ray by producing a small flash of light or a scintillation .  The scintillation occurs , when scintillator electrons, excited by the energy of the photon , return to their ground state . The detector crystal is mounted on a photomultiplier tube which converts the scintillation into an electrical pulse.  Semiconductor detectors A semiconductor detector is a radiation detector which is based on a semiconductor , such as silicon or germanium to measure the effect of incident charged particles or photons.

11. MULTICHANNEL ANALYZER The MCA contains most of the system’s electronics. • All of the MCA components might be housed in a single stand-alone unit. In some cases, this might be a portable hand-held device. • In the laboratory, the memory, display and analysis functions of the MCA are usually handled by a computer. The rest of the MCA’s electronic components might be housed in a single “box” connected to the computer. In other cases, the MCA electronics might consist of several modules arranged in a NIM bin . It counts the pulse from the detector , measure the size of the pulse. AMPLIFIER The amplifier also changes the pulse shape. It shortens the long tails on the pulses coming from the preamplifier and rounds off their leading edge. • This makes it easier to measure the height of the pulses. • The amplifier also filters out electronic noise (random fluctuations in the baseline voltage) .

12. ANALOG DIGITAL CONVERTER Output pulses from the amplifier are analog. • Digital - Digital information has discrete values . It is easier to store and manipulate digital data. Output pulses from the ADC are digital . The different types of ADCs measure the pulse heights in d ifferent ways.The results of the ADC’s analysis of the pulse sizes is stored in a memory. The narrower the peaks, the better the resolution. Narrower peaks (better resolution) means a greater ability to distinguish gamma rays of similar energies.

13. ADVANTAGES AND DISADVATAGES Fast & efficient , multinuclide analysis can be done. Non destructive in nature. Detailed energy information available. Instruments can be portable. Measure isotopic composition Usually requires large sample. Less sensitive to lower energy gamma rays. High cost experimental setup. Safety concerns from exposure to gamma radiation.

14. APPLICATIONS T hey are extensively in the studies of :          Nuclear structure          Nuclear transitions and nuclear reactions.           In space research such as water detection on planets.           It also used for the elemental and isotopic analysis of airless bodies in the solar system , especially the moon and mars.  Gamma rays are used in :          Medicine ( radiotherapy )          Industry ( sterilization , disinfection..)          Nuclear industry Environmental monitoring Geological mapping               

15. Nuclear Physics: Gamma ray spectroscopy helps researchers study the energy levels and transitions in atomic nuclei, providing valuable insights into nuclear structure and behavior. Environmental Monitoring: It's used to detect and quantify radioactive isotopes in the environment, aiding in environmental protection and nuclear safety. Medical Imaging: Gamma ray spectroscopy is used in gamma cameras and PET scanners for medical imaging, helping diagnose diseases and monitor treatment. Archaeology: It can be used to analyze the composition of artifacts, dating techniques (thermoluminescence dating), and detecting forgeries in art and artifacts. Nuclear Medicine: In addition to imaging, it's used in radiation therapy to precisely deliver radiation to cancerous cells. Space Exploration: Gamma ray spectrometers are used in space missions to study the composition of celestial bodies like planets and asteroids.

16. Industrial Applications: It's used to inspect materials for defects, analyze alloys, and monitor processes in various industries, including manufacturing and oil exploration. Homeland Security: Gamma ray spectroscopy is employed for detecting illicit nuclear materials at borders and security checkpoints. Nuclear Waste Management: It's crucial for characterizing and monitoring radioactive waste to ensure safe disposal and storage. Astronomy and Astrophysics: It's used to study celestial gamma-ray sources, including gamma-ray bursts and active galactic nuclei. Food Irradiation: It's used to ensure the safety of food products by detecting and measuring radioactive contaminants and pathogens. Radiation Dosimetry: Gamma ray spectroscopy is essential for measuring and monitoring radiation doses in medical settings, research facilities, and nuclear power plants to protect workers and the public.

17. Environmental Remediation: Gamma ray spectroscopy assists in assessing and remediating contaminated sites by identifying and quantifying radioactive contaminants. Homogeneous Catalysis Research: In chemistry, it can be used to investigate catalysts and reaction mechanisms involving gamma-ray emitting isotopes. Forensics: Gamma ray spectroscopy can be used in forensic investigations to analyze trace evidence, such as gunshot residue. In the field of biology, gamma ray spectroscopy has several important applications: Radiation Biology: Gamma rays are used in radiation therapy to treat cancer. Gamma ray spectroscopy helps ensure the accurate delivery of radiation doses to target cancer cells while minimizing damage to healthy tissue. Mutation Studies: Gamma rays can induce mutations in organisms. Researchers use gamma ray spectroscopy to control and measure the dosage of radiation for mutation studies, which can help in selective breeding and genetic research.

18. Radioisotope Labeling: Gamma-emitting radioisotopes are used as tracers in biological research. Gamma ray spectroscopy helps researchers track the movement of these isotopes in living organisms, allowing for the study of metabolic processes and disease mechanisms. Environmental Radioactivity: Gamma ray spectroscopy is used to monitor environmental radioactivity levels, including the presence of radionuclides in soil, water, and air. This is important for assessing potential health risks and environmental impacts. Carbon Dating: Gamma ray spectroscopy plays a role in radiocarbon dating, a method used to determine the age of archaeological and biological samples containing carbon. It relies on measuring the gamma rays emitted by radioactive carbon isotopes. Nuclear Medicine: In addition to diagnostics, gamma ray spectroscopy is used in nuclear medicine for therapeutic purposes, such as targeted radiation therapy for hyperthyroidism and certain types of cancer. Protein Crystallography: Researchers use gamma-ray spectroscopy to study the crystallography of proteins. This helps determine the atomic structure of proteins and aids in drug design and understanding biological processes. Quality Control in Food Irradiation: Gamma ray spectroscopy is employed in the quality control of food products treated with ionizing radiation for preservation. It ensures that the proper dosage is applied to kill pathogens and extend shelf life. Radiation Safety: In biological labs and nuclear facilities, gamma ray spectroscopy is used for radiation safety assessments to protect researchers and workers from excessive radiation exposure. These applications demonstrate the significance of gamma ray spectroscopy in advancing our understanding of biology, enabling medical treatments, and ensuring the safe use of radiation in various biological and environmental contexts.

19. Quality Control in Food Irradiation: Gamma ray spectroscopy is employed in the quality control of food products treated with ionizing radiation for preservation. It ensures that the proper dosage is applied to kill pathogens and extend shelf life. Radiation Safety: In biological labs and nuclear facilities, gamma ray spectroscopy is used for radiation safety assessments to protect researchers and workers from excessive radiation exposure.

20. REFERENCES Biophysical chemistry ( principles and techniques) , 4th edition by Avinash Upadhyay, Kakoli Upadhyay, Nirmalendu  Nath . Gamma ray spectroscopy ; wikipedia. https://microbiologynote.com/gamma-ray-%CE%B3-ray-spectroscopy/

21. THANKS