Need Help Co-60 Shielding Mcnp Activity Input

In summary, the conversation discusses how to include the activity of a Co-60 source in MCNP code. The activity is measured in Bq or Ci and represents the initial strength of the flux of photons. It is important to choose an activity that gives enough photons for the scenario. The conversation also covers where and how to add the activity to the code and references a primer on MCNP for more information. In the end, it is determined that the activity may not be needed, as the number of decays can be used to determine the activity and scaled for the desired effect.
  • #1
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Greeting,

I am trying to figure out how can I include the activity of a Co-60 source in MCNP code.
I have the following problem Co-60 source in a cylinder surrounded by concrete. I just need to know how to include the source activity and whether it should be in Bq or Ci.

Thank you in advance
 
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  • #2
I'm not exactly sure how to answer your question for I know little how Monte Carlo calcs are actually carried out but activity is a measure of disintegrations per unit time the Becquerel being the most transparent as 1 Bq = 1 dist/sec. where as ` Curies is 3.7E10 dps. The activity represents the initial strength of the flux of photons whose history is to be developed. So chose an activity that gives enough photons.that will participate in your scenario..
 
  • #3
gleem said:
I'm not exactly sure how to answer your question for I know little how Monte Carlo calcs are actually carried out but activity is a measure of disintegrations per unit time the Becquerel being the most transparent as 1 Bq = 1 dist/sec. where as ` Curies is 3.7E10 dps. The activity represents the initial strength of the flux of photons whose history is to be developed. So chose an activity that gives enough photons.that will participate in your scenario..
Thank you for your reply. I'm trying to figure out where and how to add it to my code more specifically how to add it to the material card
If you have an example of the material section with activity identified, please share. Thank you.
 
  • #4
gleem said:
I'm not exactly sure how to answer your question for I know little how Monte Carlo calcs are actually carried out
It sound like you are asking a question that should be answered in the documentation.
 
  • #5
gleem said:
It sound like you are asking a question that should be answered in the documentation.
What documentation, are you referring to the manual?
Well, the manual doesn't specify how to input a source activity.

Thanks for your help.
 
  • #6
Are you sure you need the activity as input and not just the spectrum of gammas from a given decay?
 
  • #7
gleem said:
Are you sure you need the activity as input and not just the spectrum of gammas from a given decay?
Ok, so here is what I m trying to simulate, from left to right, Co-60 with an activity of 1 Ci in a cylindrical cask, concrete wall 2 ft away from the source, then detector. I need to find the dose behind the concrete wall using mcnp. I am new to MCNP and I m trying to learn it but got stuck on the activity portion.
 
  • #8
Check out this primer on MCNP http://cmpwg.ans.org/mcnp/primer.pdf

If you needed the activity you would also need the half -life. In the calculation you generate a radiation emission (decay) and follow its history to a specific location AFAIK. You continue to generate these emissions until you achieve a specified precision in the specified units of interest. You do not need to specify activity since you only need to generate enough decays to get a result that you want. From the result you know the number of disintegrations that produced that result from which you determine the activity. You can then scale the activity to determine the effect for that activity.
 
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1. What is Co-60 and why does it need shielding?

Co-60, also known as cobalt-60, is a radioactive isotope used in medical and industrial applications. It emits high-energy gamma rays, which can be harmful to humans if not properly shielded. Therefore, proper shielding is necessary to protect individuals from the radiation.

2. How does MCNP calculate the activity input for Co-60 shielding?

MCNP (Monte Carlo N-Particle) is a computer code used for simulating the transport of particles through materials. To calculate the activity input for Co-60 shielding, MCNP uses a combination of the material properties, geometry, and source strength to determine the amount of shielding needed to reduce the radiation to a safe level.

3. What factors affect the required shielding for Co-60?

The amount of shielding needed for Co-60 depends on several factors, including the source strength, type of material used for shielding, distance from the source, and the geometry of the shielding. The thickness and density of the shielding material also play a significant role in determining the level of protection.

4. How accurate are the results from MCNP for Co-60 shielding calculations?

The accuracy of MCNP results for Co-60 shielding calculations depends on the input parameters and the assumptions made in the simulation. If the input data is accurate and representative of the real-world scenario, the results from MCNP can be highly accurate. However, it is always essential to verify the results using experimental data when possible.

5. Can MCNP be used for other types of radiation shielding besides Co-60?

Yes, MCNP can be used for various types of radiation shielding calculations, including gamma, neutron, and beta radiation. The code can also simulate different materials and geometries, making it a versatile tool for radiation shielding design in various applications.

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