Rad Pro: J613 tube conversion factor

[TzOk83]

I have noticed very low background radiation levels with this tube. In your description, I've found that you are using 64.8 cpm/µSv/h (9,5 cpm/mR/h) for both J613 and J614, but on the J614 datasheet I found online, they stated 5 cpm/mR/h, which is ~34,2 cpm/µSv/h. So I've set 33,9 cpm/µSv/h, and now my long-time average readings are more or less on par, with my old RKSB-104.

[Gissio]

Could you please share the link to the J614 datasheet?

Supposing the HH614 is similiar to the J614 (they also look alike), according to https://github.com/Gissio/radpro/blob/main/docs/tubes/HH614.jpg, the conversion factor should be 10 cps/mR/h.

In general, it is a bad idea to compare background levels of different tubes, as the tubes themselves emit radiation. It would be more appropriate to compare the radiation levels with a test source.

Update: I think I found it in Rad Pro's own repository: https://github.com/Gissio/radpro/blob/main/docs/tubes/J-tube%20properties.pdf. Now the question is: what is the correct conversion factor?

[TzOk83]

The one from Rad Pro is the one I've also seen, it is sometimes labeled G-M World. Nevertheless, when I enter 33.9 cpm/µSv/h I have readings ~0.1 uSv/h, which correspond to hourly updated National Atomic Agency reports for background radiation in my area (0.091 uSv/h). My RKSB-104 gives readings between 0.09 and 0.120 uSv/h. With the default setting, I've got roughly half of that reading.

[Gissio]

Excellent observation. Will be updated in the next release. Thanks a lot.

[TzOk83]

cps/mR/h to cpm/uSv/h conversion is 1 cps/mR/h = 6 cpm/uSv/h (you seem to use a value of 6.84 in your conversions), so 5 cps/mR/h = 30 cpm/uSv/h. After 24h background radiation comparisons with RKSB-104 (dual SBM-20 tubes, no averaging, just a simple rule, that counts during 280 sec. = nS/h) this is the best sensitivity value for my unit.

[Gissio]

Ok!