Nuclear- Americium Smoke Detectors

Smoke detector is a very important safety device because it is use in every building and house to prevent serious damage and life threatening consequence that is cause by fire. This device is used by everyone in the world to keep property safe and save people life. There are two types of smoke detectors the first type is a Photoelectric smoke detector which is smoke detector device that use an optical sensor, the second type is an Ionization smoke detectors which is a smoke detector device that uses a small amount of radioactive material to detect smoke. People commonly use the Ionization smoke detectors because it is more reliable since it can detect fire in a wider range of condition. The last reason why Ionization smoke detector is more popular than Photoelectric smoke detector is because it is cheaper to purchase and install. Due to this reason, this discussion post is based on Ionization smoke detector.

The radioactive material that is use by the Ionization smoke detector is Americium-241. The amount of Americium-241 require for each detector is only around 1.0 microcurie. This radioactive material doesn’t exist naturally on its own instead it is the byproduct from the fission of Plutonium-239 when they irradiated with neutrons. Fission is when atom splits into smaller part to become more stable and this will decrease the mass of that element. During this reaction, beside just splitting some fraction of the atoms start to absorb two neutrons to form plutonium-241. The plutonium-241 will be taken out of the reaction so that it will undergo beta decay and form Americium-241. Beta decay is a radioactive decay where electron will be emitted from the nucleus. The last process will last the longest because plutonium have a half-life of 14 years. Half-life is the time that will take an radioactive atom to decay.  A newly bought Ionization smoke detector contain 100% Americium but after 30 years 4.7% of the Americium will decayed into neptunium. This show that Ionization smoke detector is a very reliable smoke detector because Americium have a half-life of 432.2, which is way longer than the time the smoke detector will be in use.  This also means that people doesn’t have to change the Americium-241 inside the smoking chamber because the radioactive atom will last the whole lifetime of the user.

This smoke detector work by having a positive and negative electrode inside the detecting chamber. The negative electrode is located on top, while the positive electrode is located right at the bottom of the negative one. In order for the smoke detector to work a low and steady electric current is apply to the two electrode so that the electrode will have a charge. There is an open in the chamber that allow air inside the room to flow inside the chamber, while this occur the Americium-241 inside the chamber continuously decay into Neptunium-241. Alpha decay is when two protons and two neutrons that are bound together is emitted from the nucleus. When Americium-241 decay it emit alpha particle, this particle will collide with oxygen and nitrogen molecules in the air. When it collide with the air molecule it will cause the molecule to ionise, which means that the emit alpha will knock the electron from the atom. As a result, negatively charge electron and positively charged atoms will be left in the chamber. These charge particle will be attracted to the electrode that have an opposite charge, for instance the positively charged atom will be attracted to the negatively charged electrode. This process produce a small amount of current that is detected by the electrical circuit in the smoke detector. The smoke detector will be able to detect that there is a fire because when smoke enter the chamber the electric current will drops and this signal will triggers the alarm to release the beeping sound. The reason why the electric current drops when smoke enter the chamber is because the emit alpha particles will collide with the smoke particle instead of the air particle. Due to this reason, there will be no negatively charge electron or positively charged atom because the alpha particle cannot ionise the smoke particle. This will cause a drop in the electric current and cause the smoke detector to release a beeping noise. To have a look at the animation of the particle movement inside the chamber, follow this link: http://www.passmyexams.co.uk/GCSE/physics/alpha-particles-in-smoke-detectors.html

In conclusion, Ionization smoke detector is very important and should be install in every houses, buildings and public infrastructures because it can protect these place from serious damage that is caused by fire and save people life.  

Work Cited

Modern Chemistry by Holt McDougal

http://www.world-nuclear.org/information-library/non-power-nuclear-applications/radioisotopes-research/smoke-detectors-and-americium.aspx

http://large.stanford.edu/courses/2011/ph241/eason1/

http://www.passmyexams.co.uk/GCSE/physics/alpha-particles-in-smoke-detectors.html

http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/radiation/radioisotopesrev3.shtml

Nuclear- Nuclear Fusion Power

Nuclear Fusion Power is one of the newly possible eco-friendly way to produce huge amount carbon-free energy. This technology is not use by anyone yet to produce energy (electricity) because it is still in the research process. Joint European Torus which is the world's largest tokamak have proof that nuclear fusion is a possible way to generate clean energy but they have not discover an appropriate way to produce these energy in an industrial scale and decrease the amount of energy required for the nuclear fusion to take place. As a result, this technology still remain as a mystery. 

If we are able to use Nuclear Fusion Power in the future we will no longer have to worry about energy shortage because this technology produce energy more efficient than fossil fuel. Currently, this technology is considered to be the most efficient at producing energy because with one kilogram of fusion fuel it can produce the same amount of energy generated from 10 million kilogram of fossil fuel. The next advantage of Nuclear Fusion Power is that the only byproduct produce from this technology is a small amount of helium, which is an inert gas that have nothing to do with atmospheric pollution. The third advantage of this technology is that it only use tritium and deuterium, which is an abundant resource that are available on earth. Deuterium can be extracted from seawater, while Tritium can be produced from lithium that is found in the earth’s crust. The last advantage is that this technology would not leave a long-life radioactive waste behind because it can be safely recycle and will dispose within 100 years.
Watch the video below if you want to find out more about Nuclear Fusion Power research in different countries:

The way the Nuclear fusion power work actually follow the fusion concept in nuclear chemistry. Fusion is when the nuclei combine together to become more stable and this result in an increase in the mass of the atoms. Similarly, in the Nuclear fusion power the goal is to combine the deuterium and tritium to produce helium. Deuterium is a stable atomic species that is an isotope of hydrogen, which contain a proton and a neutron. Tritium is is a not stable atomic species that is also an isotope of hydrogen, which have one proton and two neutrons. To achieve a high fusion reaction rate the two hydrogens species (fuels) must be heated to a temperature that is over 100 million degrees celsius and this will cause the fuels to change from a gas state into a plasma state. Plasma is a state of matter where the particles that make up the atom lose most of it electrons because of its high-temperature, in the context of nuclear chemistry plasma is a very hot mixture of electrons and positive nuclei. This is why the negatively-charged electron separated from the positively-charge atomic nuclei when the fuel is heated. This result in a plasma that is a million times less dense than air. The plasma are extremely hot so it can not come in contact with any type of materials. As a result, scientists is still working to find the best way to confined these plasma, some of the possible ways that is found so far include Tokamak and Stellarator. Magnetic confinement used Tokamak, which confined the plasma by creating a strong magnetic fields. Figure 1 is a Tokamak, from this figure it show that Tokamak use multiple magnets one of it is located in the middle while the rest is wrap around the plasma like a coil and also around the top and bottom in order to control the position and shape of the plasma. Stellarator also use magnetic field to confined the plasma but the location that the magnet are place is different. Figure 2 show that the magnet that Stellarator place around the plasma are like a twisted coil, the purpose of the twist is to control the direction of the plasma so it will remain inside the chamber.

Figure 1. Tokamak

Figure 2. S Stellarator 

Normally, it is not possible for fusion to occur because they are not close enough to each other to collide. This is because the positively charged nuclei have a strong repulsive electrostatic force that prevent them from getting close to each other. Electrostatic force is the force between particles causing by their electric charges. But this problem can be solve if apply more heat to increase the temperature because it will cause the nuclei to move faster and they will eventually reach a speed that allow them to overcome the electrostatic forces and shorter the range so they are closer to each other. This will allow nuclei to fuse because the attractive nuclear force will outweigh the electrostatic force and when they fuse a huge amount of energy will be release. As a result, when Deuterium fuse with Tritium the product that is produce is a free neutron and helium-4, which means that it contain two protons and two neutrons. Below is an equation that show the fusion process. The amount of energy release from this fusion is 17.6 MeV and it is in the form of kinetic energy. The amount of energy produce each time will vary depending on the amount of Deuterium and Tritium used but the formula that can be use to calculate the energy is the Mass–energy equivalence formula (E=mc^2).

In conclusion, Nuclear Fusion Power is very important because if the research is success and the technology is put into use in the future people will not have problem with energy shortage. Moreover, people will also be able to reserve the remain fossil fuel that have not been use to generate energy. Lastly, people will be able to reduce global warming and improve air quality because this technology does not produce any green house gas or poisonous gas that will affect people's health.

Please check this link to see the animation of the fusion reaction: http://www.ccfe.ac.uk/How_fusion_works.aspx

Work Cited
Modern Chemistry by Holt McDougal

http://www.ccfe.ac.uk/introduction.aspx

http://www.ccfe.ac.uk/How_fusion_works.aspx

http://www.world-nuclear.org/information-library/current-and-future-generation/nuclear-fusion-power.aspx

http://www.polymedia.ch/files/RP/Articles/857/images/7569_2_p13_Lausanne_W7X-2.jpg

https://www.britannica.com/science/deuterium

http://www.physics.isu.edu/radinf/tritium.htm

Nuclear- Positron Emission Tomography (PET)

Positron Emission Tomography (PET) scan allow doctors to scan the internal structure of a human body to see how the tissues and organs function so they can identify if an individual carrier any of the following conditions, which include cancers, heart disease and brain disorder. Beside detecting if an individual have any of the problem above, it can also assess the effectiveness of treatment plan, determine specific problem within the main problem above and determine the spread of cancer inside the body. As a result, Positron Emission Tomography is commonly used by oncologist, neurologists, neurosurgeons and cardiologists.

The way that the Positron Emission Tomography machine work is by detecting the gamma rays and send it to the computer. The computer will analyze the gamma rays into information that will be use to create the image. In order for the gamma rays to be emitted from the patient body the patient will need to consume tracer, which can either be injected, swallow or inhale into the body. Tracer is a chemical compound that have a radioactive atom attach to the chemical substance that is used by the particular organ or tissues during it metabolic process, which is a process where the cells produce energy and other substance to sustain its life. Due to this reason, there are many type of tracers because different organ or tissue require different tracer. For example: The tracer that is use for PET brain scan is fluorodeoxyglucose, which is made out of a flouride-18 and glucose because the brain use glucose during it metabolism process. The structure of this tracer is shown above. When the tracer enter the body and reach the target organ or tissue it will gather in the area with the highest levels of chemical activity because this is where the disease will take place. When this occur the radionuclide in the tracer will undergo radioactive decay process where it will break down the atomic nucleus and emit positron. Positron is a particle that has a positive charge and has the same mass as an electron. The positron will collide with an electron in the tissue to release energy in the form of gamma ray, which is an electromagnetic waves that is emitted when the nucleus change from an excited state to a ground energy state. Afterward the scanner will detect the Gamma ray and use the computer to process it into an image. The affect tissues will appear to be very bright because this is where most of the radionuclide gather up and emit the most gamma ray.

In conclusion, it show that Positron Emission Tomography scan is very important in the medical field because it is use to detect some of the most serious diseases that is hard for doctor to cure, which are cancer, heart disease and brain disorder.

Work Cited
Modern Chemistry by Holt McDougal

http://www.hopkinsmedicine.org/healthlibrary/test_procedures/neurological/positron_emission_tomography_pet_scan_92,p07654/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1126321/

https://www.radiologyinfo.org/en/info.cfm?pg=pet

http://www.mayoclinic.org/tests-procedures/pet-scan/basics/definition/prc-20014301
http://interactive.snm.org/docs/PET_PROS/FDG_K_Zukotynski.pdf
http://199.116.233.101/images/thumb/3/35/Glucose_vs_FDG_Diagram.png/500px-Glucose_vs_FDG_Diagram.png