What are the units of radiation dosimeters

1. Radioactive activity unit:

This unit represents the number of atoms of a radioactive element or isotope that decay per second, measured in becquerels, abbreviated as (Bq).

Absorbed dose is a physical quantity used to represent basic metrology. After a ray interacts with an object, it represents the value of radiant energy absorbed by a unit mass of the object, with the unit of (Gray,Gy). 1Gy represents 1 joule per kilogram, which is a large unit. In practical applications, we only use one-thousandth or ten-thousandth of this unit. Use mGy,μGy or nGy, etc. as the actual measurement units.

2. Equivalent dose:

Different forms of radiation can produce different biological effects, so the absorbed dose does not equal the biological effect of the same degree. Generally, when we need to use the same scale to represent the impact of multiple types of radiation on the human body, the equivalent dose unit can be adopted, which comprehensively considers the number of radiation weight factors.

The equivalent dose is expressed in J·kg-1. To better distinguish it from the absorbed dose unit, the specific name used for the equivalent dose unit is Sievert, which we call "sievert" and its symbol is "Sv". In applications, the main units adopted are mSv, μSv, nSv, etc.

In previous measurement processes, the water quality values were mainly measured in the form of dose rates, indicating the values measured per hour. When it was necessary to detect the absorbed dose value after staying at a certain position for one hour, the product of the dose rate and the retention time could be used. Generally, the level values measured were also in the form of dose rates, that is, the dose per hour.

3. Effective dosage:

This is a unit that describes the degree to which radiation affects the health of the human body. In most radiation protection industries, the concept of effective dose is adopted.

The relationship between the random effects produced by radioactive radiation exposure and the equivalent dose is related to the exposed tissues and organs, etc. As different tissues have different sensitivities to radiation, in order to more conveniently calculate the total danger of radiation to exposed organs and tissues, the concept of tissue weight factor was adopted in the radiation protection industry, thus generating the effective dose unit. The effective dose unit is millisieverts/millisieverts (mSv) or microsieverts/microsieverts (μSv), with 1Sv = 1000mSv. 1mSv = 1000μSv.

1 Rontgen (R) = 10,000 microsieverts (μsv) =1 rem (REM) =1Gy =1 J·kg-1

In a normal environment where radiation does not exceed the standard, the effective dose of natural background radiation that the human body receives is approximately 2.4mSv (world average).

Absorbed dose D: Unit Gy(gray) = 1J/Kg, auxiliary unit rad(rad) = 0.01Gy
Equivalent dose H: Unit Sv(sievert) = 1J/Kg, auxiliary unit rem(rem) = 0.01Sv

There is a certain relationship between the effective dose and the absorbed dose: H=Q×D (Q is the radiation quality factor), and the relatively new term is H=Wr×D (Wr is called the radiation weight factor), but they are essentially the same.
Effective dose E: Unit Sv(sievert) = 1J/Kg

E=∑t Wt×Ht(Wt represents the number of weight factors of the organ or tissue, and Ht is the equivalent dose of radiation received by the tissue)

The dose rate we often refer to is the degree of change in radiation dose over time, which can be expressed in various ways. Common ones include absorbed dose rate, equivalent dose rate, and effective dose rate, etc. The corresponding dose rate can be obtained after the radiation dose has been exposed for a certain period of time, with the unit being /S.
CPM and CPS refer to the particle count released by a personal radiation dosimeter during the sample detection process. CPM represents the count per minute, while CPS indicates the count per second.
When multiple rays are present simultaneously in the detection environment, it is recommended to use equivalent dose units.
The absorbed dose unit is mainly used in the detection of various types of radiation and exposed objects, etc. When measuring the intensity of Y-rays, nGy/h is usually adopted as the measurement unit, which expresses the absorbed dose value measured per hour. Absorbed dose is one of the important units in applications that can describe the concentration of radiation absorbed by an object.
The units of a radiation dosimeter mainly include radioactive activity, equivalent dose and effective dose. They can be applied in different environments to represent the value of radiation intensity. Therefore, before using a radiation dosimeter, we should first correctly understand what units it has, so as to better analyze environmental radiation data.