My questions:
-are transuranic elements and radioisotopes produced in exactly same way ie.using nuclear reactor and particle accelerator?
-Is it not necessary for nuclear fission to occur in nuclear reactor and nuclear fusion to occur in particle accelerator ?
-Will knowing the location discovered and how it is produced for recent discoveries of elements be enough?
I have an assessment coming up so would you mind checking if my notes are correct and if the main important details are mentioned? thank you
Describe how transuranic elements are produced
Neutron bombardment:
- Natural elements are immersed in a nuclear reactor and bombarded with neutrons (or other particles) to produce higher elements as nuclear fission occurs
Particle accelerator
-transuranic element atomic number>96 are made by bombarding heavy nucleus with high speed small positive nucleus (e.g. He, C or Boron) in accelerators, synchrotrons, and cyclotrons.
Describe how commercial radioisotopes are produced
Nuclear reactors
-Bombard target nuclei with slow neutrons produced by fission of uranium-235. The nucleus absorbs neutrons hence producing a neutron-rich radioisotope.
Particle accelerators
-A machine uses electric and magnetic fields to accelerate charged particles such as protons, or nuclei (eg.Helium) or ion of other atoms (eg. Hydrogen-2 ions, Helium-3 ions) to collide with target nucleus. Nuclear fusion occurs and neutron-deficient radioisotope is produced.
eg. (nuclear fusion) Fluorine-18 is prepared in a cyclotron by bombarding nitrogen-14 with helium nuclei.
Identify instruments and processes that can be used to detect radiation
-Photographic film- Darkening of photographic film indicated the presence of radioactivity. The darkening is due to formation of silver halide crystals as radiation is absorbed by silver salts in the film.
-Cloud Chamber - device that consists a container of supersaturated vapour of water or alcohol. As radiation travels through the device, it ionises surrounding air molecules which causes vapour molecules to condense onto these ions, to produce visible cloud tracks/ trails.
-Scintillation counter:
- When certain substances like ZnS absorbed energy from alpha, beta and gamma rays, they emit flashes of light which can be collected and amplified in a photo multiplier. Thus, an electrical pulse can be generated and recorded by a counter
-Used to measure the amount of radiation exposed to a person who has taken a body scan
Geiger-Muller counter
- Best for detection of alpha and beta radiation but cannot tell difference between alpha and beta particles
- Consists of a sealed glass/metal tube with inside filled with argon gas and with a thin mica window at one end to allow particles to enter
- Particles enter ionise gas molecules (e.g. argon), emitting electrons which accelerate towards the positive electrode, and ionising more gas as they proceed in their path and create an electrical pulse
- GM counter records the electrical pulse and convert it to audible clicks
Medical and radioisotopes uses and chemical properties
Cobalt-60: (industrial/medical)
Chemical properties:
Chemically inert
Gamma emitter
Long half-life of 5.3 years
Relating uses to chemical properties:
- it is an emitter of gamma rays which can penetrate the materials such as metals, paper, rolled steel and detected on the other side using radioactive film, therefore can measure thickness of these materials or detect faults in metal casting and cracks in aircraft wings.
-The gamma radiation it emits used to sterilise food eg. Strawberries to minimise spoilage and extend shelf life, and medical supplies such as disposable syringes and bandages. Food on a conveyor belt is gamma irradiated by passing it through a chamber containing a safely shielded Co-60 source.
Benefits
-it is chemically inert therefore has relatively low emission of radiation also limits the potential damage to anyone working with the radioisotope.
-potent gamma emitter - Gamma rays can easily penetrate hermetically sealed packaging and the contents, killing harmful microbes such as bacteria, viruses and fungi. They have sufficient energy to destroy bacteria but not enough to make food radioactive.
-has a reasonably long half-life of 5.3 years since it is chemically inert hence do not require frequent replacement/do not need to be produced on site and can be readily used to treat cancer patients
-Provides effective treatment of many cancerous tumours in sensitive organs because it releases beta and gamma radiation which can easily penetrate and kills abnormal cells
-Cheaper methods of diagnosis and treatment of medical illnesses and cancer
-Provides non-invasive, convenient diagnostic techniques to trace medical illnesses and problems
-medical sterilisation which is more effective than the use of antiseptics and heat treatment
Concerns
-There are concerns that gamma radiation can destroy vitamin content in food and may lead to the formation of harmful compounds in the food. In addition, workers must be protected from irradiation.
-Continued exposure to radiation can lead to diseases such as tissue damage, tumours, cancer and genetic damage
-Without further research, the long-term effects in irradiation of food, are unknown
Technetium-99m (medical):
Chem properties:
-short half-life of 6 hours
-emits low energy gamma
-can be attached to a range of biological carriers
-relatively unstable and reactive
Relating chemical prop to uses:
-used as a biological tracer for diagnostic imaging. It can be attached to biological molecule which will concentrate in the targeted organ such as brain, kidney, bones liver and spleen and injected into the body. Then, it will emit gamma radiation which can easily penetrate and detected in various part of body using a gamma camera (scintigraphy) and pinpoint blood clots, constrictions, heart defects and size and location of cancer growth, etc.
eg. Tc-99m phosphonates is used to diagnose skeletal bone problems
Benefits:
-short half-life of 6 hours which is short enough to minimise the exposure of radiation to patient and long enough to examine metabolic processes occurring in the body
-emits low energy gamma radiation which minimises damage to healthy cells/tissues, but can still be detected in the body by a gamma ray sensitive camera.
-Can be attached to a range of biological carriers which will concentrate in a targeted organ
-relatively reactive, so it can be reacted to form a compound with chemical properties that leads to concentration in the organ of interest such as the heart, liver, lungs or thyroid.
-Can be made on site from molybdenum-99 in a transportable generator – Mo-99 is a product of nuclear fission in a nuclear reactor
-Easy to detect using small quantities
-Provides a range of non-invasive, convenient diagnostic techniques to trace medical illnesses and problems and patient experiences little or no discomfort during the test
-Cheaper methods of diagnosis and treatment of medical illnesses and cancer
-Scintigraphy can be used to produce real time images of body sections which enables observation from all angles instead of Xrays which are static images
Problems:
-It is produced in a nuclear reactor from Molybdenum which is not as dangerous as Plutonium-241 but usual safeguards are necessary (lead shielding) as long term exposure to any radiation can lead to diseases such as tissue damage, tumours, cancer and genetic damage (which leads to deformities in offspring)
Evaluation:
-Tc-99m may cause damage to tissues, or cancer when it is exposed in long term. However, it can be minimised with proper safeguards and in addition its short half-life and low frequency gamma radiation. More importantly, it can give value information concerning a wide variety of metabolic disorders or cancers without the need for invasive surgery. Therefore, there are more benefits associated with the use of Tc-99m and this makes it the most widely used medical radioisotope.
Americium-241 (industrial)
Chemical properties:
-Emits alpha and gamma radiation
-long half-life of 432.7 years
Relating uses to chem prop: (medical and industrial):
-Used in smoke detectors because it is emits alpha and gamma radiation.
When no smoke is present, the alpha particles ionise nitrogen and oxygen in the air in the detector.
When smoke is present, the smoke absorbs the alpha particles emitted, so the rate of ionisation drops and this sets off the alarm.
-Gamma radiation released from Am-241 can be used for indirect analysis of materials radiography and for quality control in manufacturing fixed gauges eg. It has been used to measure glass thickness to help create flat glass
-Gamma rays also provide diagnosis of thyroid function
-It is recently suggested for use as a denaturing agent in plutonium reactor fuel rods to render the fuel unusable for conversion to nuclear weapons
Benefits:
-Long half-life of 432.7 years so do not need frequent replacement
-Alpha particles do not themselves pose a health hazard – as they are absorbed in a few cm of air or by the detector itself
Problems:
-emits alpha and gamma radiation which can be a serious health hazard if ingested or inhaled
-Dangerous if swallowed as it would concentrate in the skeleton and continue to emit radiation which could cause some cellular damage
-Production is dangerous as it is made through the decay of plutonium-241 in a nuclear reactor which is a highly radioactive element and emits high energy gamma radiation as it decays. Hence, special precautions must be taken when handling plutonium, otherwise it can cause cancer and death
Evaluation:
-It is necessary as it can save lives by warning inhabitants of fires
Sodium-24 (industrial)
Chemical properties:
-Soluble in water
-Emit beta and gamma radiation
-Half life of 15 hours
Relating uses to chem prop:
-it is soluble in water and and used as a leak detector in damaged underground water, gas and oil pipes as it emits beta and gamma radiation. Minimal radiation is detected if it is from inside a pipe, but if the tracer leaks into the soil large radiation are detected
Benefits:
-emits beta radiation - it does not pose a major health hazard to living things because the radiation will be absorbed by the pipe itself or by its surrounding/ pipe leaks can be located without having to dig up entire pipeline.
-half-life of 15 hours – lasts long enough to find leaks and short enough so that it does not cause any serious permanent pollution to water bodies
-Non-toxic to humans or animals- although it may form organic compounds and be absorbed into the blood stream, this will not strongly affect the health of humans or animals due factors such as its life span and low intensity emission of gamma radiation
Problems:
-Not a naturally occurring isotope hence relies upon nuclear reactors for production which may cause disastrous consequences if large amount of harmful radiation is accidently released
-Radiation cause undesirable reactions in living tissue and so can cause tissue damage, cancers and/or genetic damage leading to deformities in offsprings.
Evaluation:
-It is certainly valuable in detecting leakages in industry despite some minor disadvantages which can be minimised/eliminated with strict safety precautions
Strontium-90 (industry)
Chemical prop:
-Half-life of 28 years
-emits B radiation
Uses:
-used in thickness gauges to monitor the thickness of sheet materials. Radiation from the Sr-90 is passed through the material to a detector. The intensity of the radiation detected is an indicator of the thickness of the material.
Benefits:
-Long half-life of 28 years so it can be used for extended periods of time so no need frequent replacement
Problem:
-It is similar to Calcium therefore has tendency to replace calcium and this can lead of leukaemia and bone cancer
Iodine-131 (medical)
Chemical prop:
-Half-life of 8 days
-Can be attached to biological molecule
-Emit Beta radiation
Relating uses to chem prop:
-used in medicine to diagnose and treat thyroid cancers.
-When it is tagged to NaI and injected into bloodstream, it will accumulate in the thyroid gland where it undergoes beta and Gamma decay to kill cancer cells or identify thyroid diseases by detection
Benefits:
-Relatively short half-life of 8 days which is long enough for treatment to be done but not too long such that the patient is exposed to excess radiation.
Describe recent discoveries of elements
Copernicium-227
-half-life of 0.24 milliseconds.
-It was discovered in 9th of February in 1996 at the GSI in Darmstadt Germany
-element was created by firing accelerated zinc-70 nuclei at a target made of lead-208 nuclei in a heavy ion accelerator