Radiation protection
Radiation protection, also known as radiation protection, is defined by the International Atomic Energy Organization (IAEA) as "Protecting humans from the harmful effects of exposure to ionizing radiation, and the means to achieve this". Exposure may be from a source of radiation outside the human body or as a result of internal irradiation caused by the ingestion of radioactive contamination.
There are two main types of ionizing radiation health effects. At high exposures, it can cause "print" effects, also known as "deterministic" effects due to the certainty of their occurrence, routinely marked by the gray unit and leading to radiation syndrome gloomy. For low-grade exposures, risks can statistically increase radiation-induced cancer, known as “stochastic effects” due to the uncertainty of their occurrence, usually identified by the unit filter.
It is fundamental to radiation protection to avoid or reduce the dose using simple time, speed, and shield protection measures. Exposure length should be limited to the required level, the distance from a radiation source should be increased, and the source protected where possible. To accept a personal dose in occupational or emergency exposure, for external radiation personal dosimeters are used, and for an internal dose due to a radioactive contamination attack, bioassay methods are applied.
For radiation protection and dosimetry assessment, the International Commission on Radiation Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) publish recommendations and data that will be used to determine the biological impact of certain levels of radiation. work out radiation, and so on. advise limits on acceptance of appropriate doses.
Principles:
The ICRP proposes, develops, and maintains the International System for Radical Protection, based on an assessment of the large body of available scientific studies to determine a risk equivalent to dose levels. found. The health goals of the system are “to regulate and control exposures to ionizing radiation so that definite effects are prevented, and the risks of stochastic effects are minimized to the extent that can be achieved to reasonable ".
The ICRP 's recommendations flow to national and regional regulators, who have the opportunity to incorporate them into their own law; this process is shown in the accompanying block diagram.
Exposure situations:
The ICRP recognizes existing planned, emergency, and exposure situations, as described below.
• Planned display - defined as "... where radioactive protection can be planned in advance before exposures occur, and where the magnitude and magnitude of exposures can be reasonably predicted." These are such as in professional exposure situations, where employees are required to work in a known radiation environment.
• Emergency display - defined as "... unforeseen circumstances which may require emergency protective action". This would be a critical nuclear incident.
• Current disclosure - defined as “... being like the existing ones when a control decision needs to be made”. These can be from radioactive materials that occur naturally in the environment.
Dose management:
The ICRP applies the following general principles for all controlled exposure situations.
• Restriction: Everyone must be protected from excessive risks, by enforcing individual radiation dose limits.
• Optimization: This process is intended to be applied in such circumstances as are considered reasonable. It means that “the likelihood of outbreaks occurring, the number of people exposed, and the size of their individual doses” should be kept to a minimum (reasonably known as ALARA or ALARP). It takes into account economic and social factors.
Factors in external dose taking:
There are three factors that control the amount, or dose, of radiation obtained from a source. Radiation exposure can be controlled by a combination of these factors:
1. Duration: Reduction of exposure time reduces the effective dose proportionally. An example of reducing radiation doses by reducing exposure time may be developing operator training to reduce the time it takes to handle a radioactive source.
2. Speed: Increased speed reduces dose due to the inverted square law. The distance can be as simple as manipulating a source with branches rather than fingers. For example, if a problem appears during a fluoroscopic procedure step away from the patient if possible.
3. Shield: Radiation sources can be protected by solid or molten material, which absorbs the energy of the radiation. The term ‘biological shield’ is used to include substances that are placed around a nuclear reactor, or another source of radiation, to reduce the radiation to a safe level for humans.
Inner dose:
Intravenous dose, as a result of the ingestion or ingestion of radioactive substances, may have a stochastic or concomitant effect, depending on the amount of radioactive material swallowed and other biokinetic factors.
The risk from a low-grade internal source is represented by the promised dose-size dose, which has the same risk as to the same effective external dose.
The live radio material can come in through four channels:
• inhalation of air pollutants such as radon gas and radioactive particles
• contamination of radioactive contaminants in food or liquids
• suction of valves such as tritium oxide through the skin
To monitor the density of radioactive grains in ambient air, radioactive granular monitoring instruments measure the density or presence of airborne materials.
For desirable radioactive materials in food and drink, special laboratory radiometric assessment methods are used to measure the density of such substances.
Recommended dose limits
The ICRP recommends a number of dose-taking limits in Table 8 of the ICRP 103 report. These limits are "fixed", for planned, emergency, and routine conditions. In these cases, limits are given to some open groups; [9]
• Planned publishing - boundaries set for work, medical and public. The occupational exposure limit of an effective dose is 20 mSv per year, averaged over specified periods of 5 years, with no one year exceeding 50 mSv. The public exposure limit is 1 mSv per year. [10]
• Emergency display - boundaries set for professional and public disclosure
• Custom display - reference levels for everyone open
The U.S. Department of Energy public information dose card, shown here on the right, relates to U.S. regulation, which is based on ICRP recommendations. Note that the dose rate (radiation per unit hour) has a scale in levels 1 to 4, and 5 and 6 have a scale of total accumulated dose.
Radiation shield:
Almost any material is often a shield from gamma or x-rays if utilized in sufficient amounts. differing types of radiation interact in several ways with protective material. So different flight methods are used counting on the appliance and therefore the type and energy of the radiation.
A shield reduces the intensity of radiation, which increases with thickness. this is often an abstract relationship with a gradually diminishing effect with the addition of equal slices of protective material. A size called semi-thickness is employed to live this. for instance, a manipulative shield during a shelter with ten and a half thick packs of dirt, which is about 115 cm.
The efficiency of fly matter generally increases with its number, called Z, with the exception of neutron shield, which is more easily protected by such neutron receptors and moderators as boron fertilizers e.g. boric acid, cadmium, carbon, and hydrogen.
Compared to a single-material shield, an equivalent mass of a Z-graded shield has been shown to scale back electron infiltration by over 60%. [16] it's commonly utilized in satellite-based material detectors, offering a variety of advantages:
• protection from radiation damage
• reduce rear noise for detectors
• lower mass compared to a single-material shield
The design varies, but the gradient from high Z (usually tantalum) through low Z elements like tin, steel, and copper, is typically finished with aluminum. Sometimes even lighter materials like polypropylene or boron carbide are used.
In a standard Z-ray shield, the high-Z shield efficiently dissipates proteins and electrons. It also contains gamma rays, which produce X-ray fluorescence. Each subsequent fold involves an X-ray fluorescence of the previous material, which ultimately reduces the energy to a suitable level. Each reduction in energy produces bremsstrahlung and Auger electricity, which is below the energy state of the detector. Some designs also include an outer casing of aluminum, which may be a bit like the skin of the satellite. The efficiency of cloth as a biological shield is said to its cross-section for dispersion and absorption, and to the initial estimate, it's supported the entire size of the fabric per unit area applied there. protect the road of sight between the radiation source and therefore the area. Therefore, wing strength or “thickness” is routinely measured in units of g / cm2. The penetrating radiation suddenly drops thanks to the thickness of the shield. In x-ray facilities, the lead round the room with the x-ray generator can have lead shield-like lead sheets, or the plaster can contain barium sulfate.
thank, guys
0 Comments