| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
17 May 2007 12:46:48 AM |
| Object: |
High gamma energy source |
I am trying to set up the experiment with the high energy gamma source
which would be able to produce positrons in the material by use of the
pair creation. I need to have a relatively high gamma energy for it.
Are there any natural high energy gamma sources which have a half-life
of at least days or weeks?
I found only some short-lived sources in some of the natural decay
series. They decay fast but at least they have longer lived parent
isotopes. The only radioisotope with a relatively high energy and T1/2
which I found is Bi-208 E (gamma) = 2.614 MeV.
Any other candidates?
By the way, is there anyway the active nuclear physics discussion
forum?
Jagoda
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| User: "" |
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| Title: Re: High gamma energy source |
19 May 2007 02:54:36 AM |
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In article <1179380808.857093.47990@l77g2000hsb.googlegroups.com>, writes:
I am trying to set up the experiment with the high energy gamma source
which would be able to produce positrons in the material by use of the
pair creation. I need to have a relatively high gamma energy for it.
Are there any natural high energy gamma sources which have a half-life
of at least days or weeks?
I found only some short-lived sources in some of the natural decay
series. They decay fast but at least they have longer lived parent
isotopes. The only radioisotope with a relatively high energy and T1/2
which I found is Bi-208 E (gamma) = 2.614 MeV.
Any other candidates?
For obvious reasons, any naturally occuring sources with half lives of
days/weeks (in fact with any half life short on geological scale) must
be interim elements in decay chains originating with elements with
half lives comparable or longer than geological time scales. You'll
find few of these in the Uranium and Thorium decay chains.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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| User: "Jaga" |
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| Title: Re: High gamma energy source |
29 May 2007 11:09:02 PM |
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Guys,
thanks for your help. I think, I was wrong with the idea of producing
pairs from high energy gamma source. This is not really what I wanted
to have as a high energy positron source. Yes, gamma will produce
pairs but their production would be instantenous, there will be no any
activation there and what I really wanted is to have activated probe.
I found two other ways to do it - by a so called generator source
which consist of long lifetime EC source which then decays to a high
energy positron source which decays very fast. Another way is to use
high energy alpha in (alpha,n) or (alpha, gamma) reaction. But the
cross-section for such a reaction may be pretty low.
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| User: "" |
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| Title: Re: High gamma energy source |
17 May 2007 09:13:21 PM |
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No, for what you seem to want, I really don't see you finding any
natural sources.
The isotopes that are employed for x-rays of welding joints, etc., are
manufactured using reactors, are heavily controlled, and are very
dangerous to employ. None are of natural origin.
Harry C.
On May 17, 1:46 am, wrote:
I am trying to set up the experiment with the high energy gamma source
which would be able to produce positrons in the material by use of the
pair creation. I need to have a relatively high gamma energy for it.
Are there any natural high energy gamma sources which have a half-life
of at least days or weeks?
I found only some short-lived sources in some of the natural decay
series. They decay fast but at least they have longer lived parent
isotopes. The only radioisotope with a relatively high energy and T1/2
which I found is Bi-208 E (gamma) = 2.614 MeV.
Any other candidates?
By the way, is there anyway the active nuclear physics discussion
forum?
Jagoda
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| User: "H. Wabnig .... .-- .- -... -. .. --. @ .- --- -. DOT .- -" |
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| Title: Re: High gamma energy source |
17 May 2007 02:45:03 AM |
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On 16 May 2007 22:46:48 -0700, wrote:
I am trying to set up the experiment with the high energy gamma source
which would be able to produce positrons in the material by use of the
pair creation. I need to have a relatively high gamma energy for it.
Are there any natural high energy gamma sources which have a half-life
of at least days or weeks?
I found only some short-lived sources in some of the natural decay
series. They decay fast but at least they have longer lived parent
isotopes. The only radioisotope with a relatively high energy and T1/2
which I found is Bi-208 E (gamma) = 2.614 MeV.
Any other candidates?
By the way, is there anyway the active nuclear physics discussion
forum?
Jagoda
For the isotope question you may want to join
http://tech.groups.yahoo.com/group/CDV700CLUB/
http://tech.groups.yahoo.com/group/GeigerCounterEnthusiasts/
w.
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