## Libelium is offering new technical support channels, to contact with de Technical Support team to solve any issue our doubt please contact with your sales agent or visit our contact site

 Post a new topicPost a reply Page 1 of 1   [ 3 posts ]
 Print view Previous topic | Next topic
Author Message
 Post subject: Geiger Counter - Error in ratio ?Posted: Tue Apr 02, 2013 9:27 pm

Joined: Tue Apr 02, 2013 8:02 pm
Posts: 2
Hi,

Here :
http://www.cooking-hacks.com/index.php/ ... o_servants

True or not ?

I found for Co60 :
- LDN-712 :
18cps for 1mR/h
1080cpm for 1mR/h
1080cpm for 10µSv/h
108cpm for 1µSv/h
Ratio = 1/108 = 0,009259259

- SBM-20 :
22cps for 1mR/h
1320cpm for 1mR/h
1320cpm for 10µSv/h
132cpm for 1µSv/h
Ratio = 1/132 = 0,007575758

- J305β Geiger Tube :
65cps for 1µR/s
3900cpm for 1µR/s
3900cpm for 3600µR/h
3900cpm for 36µSv/h
~108,334cpm for 1µSv/h
Ratio = 1/(3900/36) = 0,009230769

Thank you
Fred

Top

 Post subject: Re: Geiger Counter - Error in ratio ?Posted: Wed Apr 03, 2013 8:47 am

Joined: Mon Sep 28, 2009 12:06 pm
Posts: 11366
Hello Fred,

We can not help you with so little information.

Regards.

Top

 Post subject: Re: Geiger Counter - Error in ratio ?Posted: Wed Apr 03, 2013 5:18 pm

Joined: Tue Apr 02, 2013 8:02 pm
Posts: 2
Hi,

I am not sure if there is an error in calculation of ratio in this page :
http://www.cooking-hacks.com/index.php/ ... o_servants
(in section : "From counts per minute to Sieverts")

For the formula
Quote:
cpm * conversion factor = μSv/h

You say
Quote:
LDN-712 tube is 0.01" and for the "SBM-20 is 0.0057

For cobalt 60 :
- I found LDN-712 tube = 0,009259259 =~ 0.01 (it's ok why not).
- I found SBM-20 tube = 0,007575758 <> 0.0057 (it's different).
But for Radium 226 :
- I found SBM-20 tube (29cps/mR/hr) = 0,005747126 =~ 0.0057 (very similar).

And now for J305β geiger tube.
I am don't understand where you found "8,77".
Quote:
1080/8.77 = 123.14 cpm/µSv/h

For J305β Geiger Tube with cobalt 60 sensibility :
In datasheet, cobalt 60 sensibility = 65cps/µR/s;

It means: 65cps for 1µR/s
-> (65cps*60)=3900cpm for 1µR/s
-> 3900cpm for (1µR*3600)=3600µR/(1s*3600)=h
-> 3900cpm for 3600µR/h
But 100µR=1µSv :
-> 3900cpm for 36µSv/h
So :
-> 3900cpm/36 for 1µSv/h
~108,334cpm for 1µSv/h
Ratio = 1/(3900/36) = 0,009230769

Best regards,
Fred

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Post a new topicPost a reply Page 1 of 1   [ 3 posts ]

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forum

 Search for:

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Libelium theme based on 610nm Style by Daniel St. Jules of http://www.gamexe.net