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Reference, Questions and Help => Nuke Q&A => Topic started by: stoicperrin on Oct 06, 2008, 01:43

Title: Radiography Question (educational help)
Post by: stoicperrin on Oct 06, 2008, 01:43
My instructor has asked a question that I don't know how to figure out. It is not in the assigned textbook which I have read cover to cover. Perhaps it needs a formula or some information not covered in this part of the class. Anyway here goes.

How many gamma rays are emitted from a 50 curie source of Co 60 in one minute?

Is there some formula to figure this out? Is this one of those so easy questions I am overlooking it?

Is this question even in the right place on this forum? LOL

I asked a couple of other students in my class and none of them have a clue, and the first time I will have to ask the instructor will be when I have to hand it in.  :-[
Title: Re: Radiography Question (educational help)
Post by: grantime on Oct 06, 2008, 02:14
1 Ci = 3.7E10 dis per second
each decay for Co-60 gives 2 gammas. 

You have 50 Ci X3.7E10 dis/sec/Ci X2 gammas/dis X 60 sec/min

Its solved by unit analysis and doesn't need an equation from book.
Title: Re: Radiography Question (educational help)
Post by: stoicperrin on Oct 06, 2008, 03:08
ahhh there we go.. even though I didn't put in part of the question you gave me the answer.

or the way to figure it out.

How many gamma rays are emitted from a 50 curie source of Co 60 in one minute?
Was supposed to say..
How many 1.33 Mev gamma rays are emitted from a 50 curie source of Co 60 in one minute?

So 50 Ci x 37 billion dis/sec/ci x1 gamma/dis x 60 sec/min

I didn't know that each disintegration gave off the 2 characteristic gammas.
Title: Re: Radiography Question (educational help)
Post by: retired nuke on Oct 06, 2008, 04:07
ahhh there we go.. even though I didn't put in part of the question you gave me the answer.

or the way to figure it out.

How many gamma rays are emitted from a 50 curie source of Co 60 in one minute?
Was supposed to say..
How many 1.33 Mev gamma rays are emitted from a 50 curie source of Co 60 in one minute?

So 50 Ci x 37 billion dis/sec/ci x1 gamma/dis x 60 sec/min

I didn't know that each disintegration gave off the 2 characteristic gammas.

Here is some future reference material that may be helpful

http://www.nndc.bnl.gov/chart/ (http://www.nndc.bnl.gov/chart/) - an interactive chart of the nuclides
http://www.radprocalculator.com/Index.aspx (http://www.radprocalculator.com/Index.aspx) - the Rad Pro Calculator - a handy tool by Ray McGinnis
Then there is the study tab at the top of the website here - lots of information.

So, what course are you taking?
Title: Re: Radiography Question (educational help)
Post by: spentfuel on Oct 06, 2008, 02:18
May be a trick question cause gamma's per second and disintegrations per second aint the same thing.

For Co-60 there are 3.699E4 gamma's per second per microcurie so there would then be 1.85E12 gamma's per second per 50 curies.

How tricky is the instructor??

sf

Title: Re: Radiography Question (educational help)
Post by: ISOCS on Oct 06, 2008, 02:32
Don't forget to multiply the answer for the 1173.2 and 1332.5 kev gammas by .9998 to account for the yield.
Title: Re: Radiography Question (educational help)
Post by: johnnieslingshot on Oct 07, 2008, 06:52
Why not just round off the the percent yeild to 100% ???  Is .0002 really going to make that much of a difference?  I have never run accross any problem that acually needed to be that precise.
Title: Re: Radiography Question (educational help)
Post by: RAD-GHOST on Oct 07, 2008, 07:21
As far as Radiography, 1.173 & 1.332 Mev, both @ 100% work!

If you didn't know about the two gamma photons associated with Co-60, wait till you get to Ir-192!   :o

RG!


   
Title: Re: Radiography Question (educational help)
Post by: retired nuke on Oct 07, 2008, 08:50
As far as Radiography, 1.173 & 1.332 Mev, both @ 100% work!

If you didn't know about the two gamma photons associated with Co-60, wait till you get to Ir-192!   :o

RG!
  
I seem to remember about 8 or 9 significant gammas (another many that aren't) , adding up to about 800 kev....

Hard lesson from my Tech A event..... ;)
Title: Re: Radiography Question (educational help)
Post by: grantime on Oct 07, 2008, 10:33
Hard lesson from my Tech A event..... ;)

I wonder how many of us have been Technician A at some point.  :o I know I have...
Title: Re: Radiography Question (educational help)
Post by: RAD-GHOST on Oct 08, 2008, 05:52
Lots of Tech "A" in the Radiography Industry!

RG!
Title: Re: Radiography Question (educational help)
Post by: RAD-GHOST on Oct 09, 2008, 05:05
Marssim,

ISOCS & Radiography!

They go together like Peas and Wing Tips!

RG!

Title: Re: Radiography Question (educational help)
Post by: thenuttyneutron on Oct 09, 2008, 06:48
http://en.wikipedia.org/wiki/Cobalt-60

Your answer is in here.
Title: Re: Radiography Question (educational help)
Post by: RAD-GHOST on Oct 09, 2008, 03:08
ROFLMAO!

Your talking MAN....I'm talking MACHINE!

RG