How to calculate radiation dose from neutron source.

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SUMMARY

This discussion focuses on calculating the radiation dose from a neutron source, specifically Californium-252 (Cf-252), with an activity of 200 kBq. Key considerations include determining the type of dose (e.g., absorbed dose, equivalent dose) and understanding the energy loss of neutrons as they pass through protective materials, such as a 30 cm thick water shield. The conversation highlights the importance of using resources like UNSCEAR, IAEA, and ICRP for guidelines and emphasizes that there is no single formula for these calculations due to varying factors like distance and body exposure.

PREREQUISITES
  • Understanding of radiation dose types: absorbed dose, equivalent dose, effective dose.
  • Knowledge of neutron interactions with matter, including moderation and shielding effects.
  • Familiarity with radiation protection principles and guidelines from organizations like UNSCEAR and ICRP.
  • Basic proficiency in using radiation measurement tools and resources, such as the NIST website for absorption coefficients.
NEXT STEPS
  • Research the calculation methods for absorbed dose from neutron sources, focusing on Cf-252.
  • Explore the effects of shielding materials on neutron energy and dose reduction.
  • Study the neutron fluence spectrum and its impact on dose calculations.
  • Review the latest recommendations and guidelines from UNSCEAR and IAEA regarding neutron radiation exposure.
USEFUL FOR

Radiation safety professionals, health physicists, medical physicists, and anyone involved in radiation dose assessment and protection strategies related to neutron sources.

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Could anybody advise me, where i can read about how to calculate radiation dose from neutron source for human body.

Excuse me for a second similar topic.
 
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Hi there,

www.unscear.org is probably the best place to find the latest recommendations from the UN and the IAEA.

Cheers
 
fatra2 said:
Hi there,

www.unscear.org is probably the best place to find the latest recommendations from the UN and the IAEA.

Cheers

Sorry, but there is information mostly about what dose a man receives from various sources.

I have not found how to calculate the dose from the neutron source.
 
Hi there,

What kind of dose are you hoping to calculate: the air-kerma, the absorbed dose, the equivalent dose, the effective dose, the ambient dose H*(10), the ambient dose H*(0.07)? Then, will your neutron source give a homogeneous field, which body part will be exposed to it, what is the energy range of the neutron source, are also question that you must answer before even trying to make any kind of calculation. Just saying that you want to find a formula on how to calculate the dose for a neutron source for a human body is not like backing cookies: there is not one recipe for it.

You can start by looking at the unscear website. The IAEA and the ICRP website are also very good place to find information on the latest on radiation exposure.

Cheers
 
fatra2 said:
Hi there,

What kind of dose are you hoping to calculate: the air-kerma, the absorbed dose, the equivalent dose, the effective dose, the ambient dose H*(10), the ambient dose H*(0.07)? Then, will your neutron source give a homogeneous field, which body part will be exposed to it, what is the energy range of the neutron source, are also question that you must answer before even trying to make any kind of calculation. Just saying that you want to find a formula on how to calculate the dose for a neutron source for a human body is not like backing cookies: there is not one recipe for it.

You can start by looking at the unscear website. The IAEA and the ICRP website are also very good place to find information on the latest on radiation exposure.

Cheers
Excuse me
There is my first thread about my question - https://www.physicsforums.com/showthread.php?t=456546"


We have:

Neutron source Cf-252

Activity of Neutron source Cf-252 = 200 kBq

The thickness of the protection of water-based = 30 cm

Weight of the man = 80 kg

Distance to a source = 1 m

Questions

How to calculate the absorbed dose for this men,if we know only activity of Cf-252, distance to a source, thickness of protection and weight of man.

How to calculate the absorbed dose from neutron source for human body? With shield and without.

If I correctly understand:

1) at first it is necessary to calculate how many energies lose neutrons transiting through protection. Whether all neutrons are decelerated transiting through protection.

2)Then, when will be known, what energy have neutrons after passage through protection, is possible to start to consider the absorbed dose
 
Last edited by a moderator:
Hi there,

Ok, but if I look at the "handbook of Chemistry and Physics", I find that Cf-252 is not a neutron emitter. It decays through the emission of an alpha particle.

Anyway, for the time being this is not relevant, except for the energy of the neutron decay. From the activity of the source, you can calculate the flux of neutrons passing through the protection and the body. From that, you can quite simply deduce the energy deposited by the neutron source. For the absorption coefficient, I normally look at the NIST website (http://physics.nist.gov/PhysRefData/).

Hope this helps. Cheers
 
are you still searching for an answer to this? if so, 252Cf emits an alpha particle 97% of the time and fissions spontaneously about 3% of the time emitting approximately 3.6 neutrons per fission. the water does moderate the energy of the neutron fluence spectrum reaching the target, but approximately 70-80% of the dose equivalent (operational quantity) originates from the uncollided neutrons. i would be glad to assist you with a little more information.
 
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