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Geiger-Müller counter with dual counts/dose rate display measuring a "point source". The dose per count is known for this specific instrument by calibration. The count rates of cps and cpm are generally accepted and convenient practical rate measurements. They are not SI units, but are de facto radiological units of measure in widespread use.
For such purposes, doses should be evaluated in terms of absorbed dose (in gray, Gy), and where high-LET radiations (e.g., neutrons or alpha particles) are involved, an absorbed dose, weighted with an appropriate RBE, should be used" Radiation weighting factors are largely based on the RBE of radiation for stochastic health risks. However, for ...
5 × 10 ^ 1: Annual: 5.7: USA NRC/ Canada CNSC occupational limit for designated Nuclear Energy Workers [9] 100 1 × 10 ^ 2: 5 years: 2.3: Canada CNSC occupational limit over a 5-year dosimetry period for designated Nuclear Energy Workers [9] 100 1 × 10 ^ 2: Acute-USA EPA acute dose level estimated to increase cancer risk 0.8% [6] 120 1.2 × ...
5: Sv: Calculated dose from the neutron and gamma ray flash, 1.2 km from ground zero of the Little Boy fission bomb, air burst at 600 m. [54] [55] 4.5–6: Sv: Fatal acute doses during Goiânia accident: 5.1: Sv: Fatal acute dose to Harry Daghlian in 1945 criticality accident [56] 10 to 17: Sv: Fatal acute doses during Tokaimura nuclear accident.
dose length product (DLP) measured in gray centimeters; rads a deprecated unit of absorbed radiation dose, defined as 1 rad = 0.01 Gy = 0.01 J/kg; Roentgen a legacy unit of measurement for the exposure of X-rays; Each measure is often simply described as ‘dose’, which can lead to confusion.
The total dose can be above the threshold for a deterministic effect, but if the dose is spread out over a long period of time, the effect is not observed. Consider the sunburn, a deterministic effect: [4] when exposed to bright sunlight for only ten minutes [5] at a high UV Index, that is to say a high average dose rate, [6] the skin can turn ...
The deterministic effects that can lead to acute radiation syndrome only occur in the case of high doses (> ~10 rad or > 0.1 Gy) and high dose rates (> ~10 rad/h or > 0.1 Gy/h). A model of deterministic risk would require different weighting factors (not yet established) than are used in the calculation of equivalent and effective dose.
A dental x-ray delivers a dose of 5 to 10 μSv. [48] A CT scan delivers an effective dose to the whole body ranging from 1 to 20 mSv (100 to 2000 mrem). The average American receives about 3 mSv of diagnostic medical dose per year; countries with the lowest levels of health care receive almost none.