Thanks Muhammad for your opinion, but i am looking for some generic data which i can use for my study. Calibration is something related to accuracy of reading, i am interested in availability and/or reliability when its operation is demanded. 

To my opinion, GM counters give only indications since they are based in internal charge generation and recording. From this point of view, the voltage stability is significant as well as the frequent check with more stable detectors, as e.g., large NaJ, HPGe etc. Moreover, GM detectors do not provide spectrum information, which is of significance regarding environmental radiation survey. GM's can scan and provide information on differentiations in radiation, regions of higher radiation exposure (in comparison to reference points). 

Concluding, I believe that  GMs are rather cheap instruments, reliable (relatively speaking), sensitive to voltage alterations and read-out equipment and can be used for  quick scanning.

Thanks Kamal Hadad

But unfortunately i can not access any of the reference u provided, not available in science direct also. If u have link, can u share?

Hi.

I think you can check the reliability of your counter by detecting a known amount of radioactivity. The closer the reading to the known value, the more reliable is the GM counter.

Calibration against a source traceable to NIST will give you accurate results, as long as the energy response of the radiation you are monitoring does not differ too greatly from the calibration source.

Sanaz and Keran

I am interested in the reliability during practical field use, not for the lab system.

Thanks @kamal, for this data which i was looking for. Although i am interested in use for some specific practice and theses are for NPP, but still better for reference in absences of other data.

the GM tube is basically just adopted as an alarm, so it is really not appropriate to be applied for any quantitative evaluation in reality. you can try to adopt others like surface barrier style of dose meter or just ion chamber for personal dosimeter as well

Thanks Lung-Kwang Pan for your views, but the facilities which really use only GM for practical applications, it may not be appropriate to use data of other monitors/detectors.