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Tuesday, 7 January 2014

BETA AND ALPHA PARTICLES

Beta radiation:

A high speed electron that is emitted during nuclear decay. This radiation had the medium ionising ability and the medium speed. It can travel close to the speed of light and can slightly ionize cells. It can be stopped by a thin sheet of aluminum and is therefore not too dangerous either. 
It is mainly used industrially when it can be used to measure the thickness of the material that is being produced. 
For example in paper mills and aluminum foil production, there is often an alpha emitter above or below the output sheets. There is then a beta radiation detector on the other side of the output sheets. If there is a high reading, the rollers adjust to thicken the sheets, if there is a low reading, the rollers adjust to thin the sheets.


Characteristics of Beta Radiation:
1. Beta radiation may travel meters in air and is moderately penetrating.

2. Beta radiation can penetrate human skin to the "germinal layer," where new skin cells are produced. If beta-emitting contaminants are allowed to remain on the skin for a prolonged period of time, they may cause skin injury.

3. Beta-emitting contaminants may be harmful if deposited internally.

4. Most beta emitters can be detected with a survey instrument (such as a CD V-700, provided the metal probe cover is open). Some beta emitters, however, produce very low energy, poorly penetrating radiation that may be difficult or impossible to detect. Examples of these are carbon-14, tritium, and sulfur-35.

5. Beta radiation cannot be detected with an ionization chamber such as a CD V-715.

6. Clothing and turnout gear provide some protection against most beta radiation. Turnout gear and dry clothing can keep beta emitters off of the skin.Cellular Mutations

Direct exposure to beta particles through inhalation or ingestion is highly hazardous. The EPA states that damage on a molecular level occurs from direct exposure to radiation, and this causes changes in cell functioning. This is especially significant for women exposed to radiation during pregnancy, as the fetus is susceptible to cellular mutation and damage. Due to the vulnerability of the body while pregnant, special care to protect a patient from beta radiation during medical exams using an X-ray machine is important, even though X-ray machines use low doses of radiation, notes the FDA.

Additional Effects

Direct exposure from beta radiation can also cause severe burns on the skin, hair loss and weakness. The Washington State Department of Health also notes that weakened immune system and nervous system damage occurs from delayed beta radiation effects. Iodine-131, which is used to treat thyroid conditions, is a beta emitter that is of significant concern as well, due to also being a source of thyroid nodule and cancer development. Ongoing studies continue to explore the effects associated with Iodine-131 on thyroid growth

Acute Illness

Radiation sickness occurs as a result of large doses of radiation over a short time frame. The Mayo Clinic explains that beta particles can cause illness through exposure to high-dose radiation sources such as detonated radioactive devices and explosives or nuclear industry leakages. X-ray machines typically use low doses pf radiation and do not commonly cause radiation sickness. Signs of acute beta radiation sickness include nausea, vomiting and dizziness. Sickness can occur within minutes to hours from high-dose exposure.

Delayed Effects

The Washington State Department of Health notes that beta radiation exposure can have delayed health effects on the body. Any amount of radiation exposure may lead to health conditions such as cancer or reproductive cell damage. Since effects from beta radiation exposure are not immediate and there is no way to determine if the exposure resulted in adverse effects, health problems can arise months to years afterward. The EPA further explains that delayed effects occur from tissue damage by beta emission and that more exposure to beta radiation increases the risk of cancer.

 
Alpha radiation is another name for the alpha particles emitted in the type of radioactive decay called alpha decay. Alpha particles are helium-4 (4He) nuclei.

Radioactivity was discovered by Becquerel, in 1896 (and one of the units of radioactivity – the becquerel – is named after him); within a few years it was discovered (Rutherford gets most of the credit, though others contributed) that there are actually three kinds of radioactivity, which were given the exciting names alpha (radiation), beta (radiation), and gamma (radiation; there are some other, rare, kinds of radioactive decay, the most important being positron, or positive beta). Rutherford (with some help) worked out that alpha radiation is actually the nuclei of helium … by allowing alpha radiation to go through the thin walls of an evacuated glass tube, and later analyzing the gas in the tube spectroscopically).


Characteristics of Alpha Radiation:

1. Alpha radiation is not able to penetrate skin.

2. Alpha-emitting materials can be harmful to humans if the materials are inhaled, swallowed, or absorbed through open wounds.

3. A variety of instruments have been designed to measure alpha radiation. Special training in use of these instruments is essential for making accurate measurements.

4. A civil defense instrument (CD V-700) cannot detect the presence of radioactive materials that produce alpha radiation unless the radioactive materials also produce beta and/or gamma radiation.

5. Instruments cannot detect alpha radiation through even a thin layer of water, blood, dust, paper, or other material, because alpha radiation is not penetrating.

6. Alpha radiation travels a very short distance through air.

7. Alpha radiation is not able to penetrate turnout gear, clothing, or a cover on a probe. Turnout gear and dry clothing can keep alpha emitters off of the skin.


Alpha radiation is given off from the decay of heavier atoms. The alpha particle is made up of two protons and two neutrons. This radiation has the lowest penetration power out of the three types. This is because it can be stopped by a few centimetres of air. For this reason, alpha decay is not regarded as very dangerous as it can be stopped so easily and cannot penetrate human skin. 

However, if it is inhaled or ingested, it is the most lethal type of radiation. This is because it is the most ionizing out of all the radiation. This means that if it comes in to contact with living cells, it can cause them to mutate, which can lead to conditions such as radiation poisoning. 
They also have many uses. 
Smoke detectors rely on alpha radiation to function. They pass alpha radiation between two charge plates. Because the alpha radiation ionises the air, charge can pass from one plate to the other. However, if there is too much smoke, the air cannot transmit as much charge and the drop is detected by the device and the alarm goes off. Alpha radiation is also used in small scale generators, such as those used in pacemakers, as they can produce a lot of heat for their size over a long period.




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