CPM to uSv/h conversion

[peterloron]

Jeff, how did you arrive at 57 for the conversion factor for CPM to uSv/h for the SBM-20? I've seen other numbers such as 40 used other places...

Thanks.

-Pete

[mightyohm]

Pete,

The 0.0057 number came from the results of another Geiger project here:
http://www.cooking-hacks.com/index.php/ ... o_servants

There is also some discussion of the accuracy of this conversion factor on brohogan's excellent DIY Geiger Counter site here:
https://sites.google.com/site/diygeigercounter/software

At this time I recommend using the uSv number as a rough indicator only, as I can't personally verify the accuracy of the conversion factor - I used the best data I could find at the time I wrote the firmware. I'm hoping I can link up with some folks that have access to actual calibration standards in the future so we can verify the numbers.

[peterloron]

Ok, I'll check those out as well. I've got a PM1621 which is reading a bit lower (difference 0.02 uSv/h) than the SBM-20 in the GC kit. The PM1621 is shielded from betas, which is probably making the difference. I'll try to hack up a beta shield for the GC kit and see what it reads then.

Nice kit, btw!

-Pete

[mightyohm]

Thanks!