الفهرس 
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Abstract
it is assumed that it is dangerous for the workers at radiation fields to be exposed to a large amount of radon and its daughters which will cause effects on long run and if increased its effects will be on short period too. It enters the body by inhalation (nose), ingestion (mouth) and through open wounds, it settles inside the body and continues to decay producing radiation that affect the surrounding tissue and cells causing their destroying with time. For this the ALARA principal was made. It states that the exposure should be as low as possible to decrease its biological effects. There are also a lot of reports, documents and guides that determines the annual dose limits for workers in the field and for public.
The precise and routine surveillance help in decreasing the exposure to radiation by knowing its concentration and give the appropriate advice and guide lines for its decrease. The exposure to radiation has proven to be life-shortening. People who are not exposed to radiation live 10% to 15% more than those exposed to it. This ensures the importance of continuous surveillance to decrease the percentage as possible to achieve a safe level for work.
This study aims to choosing the best techniques for measuring of radon gas concentration and working level, also the determination and selecting the appropriate device for every measuring condition inside laboratories where there is normal environmental conditions for temperature and relative humidity, or in mine and mills where there are harsh environmental conditions for temperature and relative humidity.
A cumulative comparison should be made between used techniques which depend on many factors such as surveillance time, efficiency, ease of use and its cost.
When choosing the appropriate techniques and best devices, lowering of annual dose can be done for workers in the radiation field, as well as the decrease of any pollution spreading to the surrounding environment to working places.
This study starts with the designing of radon calibration chamber with certain volume and special design in order to have the ability to change the temperature and relative humidity inside it. It is sealed to avoid any leakage of air which may cause change in radon concentration inside it.
Selecting of five natural rock samples with different uranium content between 35 and 850 ppm to be the basic sources of radon concentration and it was put in consideration that they have the same physical state, weight, volume and type.
Two different climatic conditions were chosen to complete the surveillance program which is high temperature and high relative humidity and low temperature and low relative humidity. It was applied to all samples and used devices.
Two techniques were used to measure radon gas and its daughters. First: active technique using RDA 200 and Tri-Met and Rolle method for measuring WL. Second: the continuous and direct measurements of radon as using RGM for direct measuring and CRM for continuous measuring.
The measured quantities are converted to annual doses due to the exposure to such levels of concentration.
This study shows an increase in the measurements was concluded for all devices with the increase of sample concentration inside the chamber with time.
RDA-200 and Tri-Met 372 devices have the best results when applied at high temperature and high relative humidity which gives them the priority of usage inside mines and mills.
The advantages of the use of Tri-Met device are that it needs short time for measurements and low weight. Its disadvantages are the height cost and it needs a lot of accessories and large number of steps for use. At last it has low stability for measurements with time as shown by the correlation factor values.
The advantages of the use of RDA 200 device are that it needs short time for measurements and low weight. Its disadvantages are the height cost and its need of a lot of accessories and large number of steps for use. At last it has low stability for measurements with time as shown by the correlation factor values.
RGM and CRM, both have the abilities to work better at normal conditions of low temperature and low relative humidity which give them the priority to work inside laboratories and homes.
The advantages of the use of RGM device is that it needs short time for measuring, also its need of a few number of steps and low cost and high stability of measurements with time according to the correlation factor values. Its disadvantage is that it is very heavy in weight.
The advantages of CRM devices is its few number of steps required at its low cost and height stability of measurements with time according to the correlation factor values and its low weight. Its disadvantages are that it needs a continuous supply of electricity and that it needs at least one hour to read the first measurements.
This study recommends the application of RDA 200 and Tri- Met devices at mines and mills according to their limited requirements to work at these places.
The application of CRM and RGM devices at laboratories according to their high requirements to work at these places.
It is very important to construct a complete comparison when choosing the set of devices and techniques for the use during the surveillance process.
Good preparation for surveillance and monitoring radiation programs including the best use of techniques and devices will achieve the goal of radiation protection which will help in decreasing the life-shortening percentage from( 10%-15% ) to less than that.