How to calculate radiation dose from neutron source.

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Discussion Overview

The discussion centers on how to calculate the radiation dose from a neutron source, specifically Californium-252 (Cf-252), for the human body. Participants explore various aspects of radiation dose calculation, including different types of doses and the influence of shielding materials.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants inquire about the specific type of dose to calculate, such as air-kerma, absorbed dose, equivalent dose, effective dose, and ambient doses, emphasizing that the calculation depends on various factors.
  • There is a suggestion that the neutron source's characteristics, including the energy range and whether it produces a homogeneous field, are crucial for accurate calculations.
  • One participant mentions the need to understand how neutrons lose energy while passing through protective materials before calculating the absorbed dose.
  • Another participant challenges the characterization of Cf-252 as a neutron emitter, noting that it primarily emits alpha particles and fissions to produce neutrons, which may affect the calculations.
  • It is proposed that the flux of neutrons can be calculated from the activity of the source, which can then be used to deduce the energy deposited in the body.
  • One participant states that a significant portion of the dose equivalent comes from uncollided neutrons, indicating the complexity of the dose calculation process.

Areas of Agreement / Disagreement

Participants express differing views on the nature of Cf-252 and its emissions, leading to uncertainty about the calculations. There is no consensus on the exact methodology for calculating the absorbed dose from the neutron source.

Contextual Notes

Participants highlight the importance of various assumptions, such as the type of dose being calculated and the characteristics of the neutron source, which may affect the outcome of the calculations. There are also references to external resources for further information, but no definitive steps or formulas are agreed upon.

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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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