Maximum amount of energy the neutron can lose

In summary, the maximum amount of energy the neutron can lose in a collision with a helium atom at rest is 16/25 of 1keV, assuming a head-on collision in the center of mass frame. If the collision is not head-on, the neutron would lose less energy.
  • #1
Sudikshya Pant
14
0
A 1 keV fast neutron (relative mass 1) in a moderator collides elastically with a helium atom He (relative mass 4) at rest. What is the maximum amount of energy the neutron can lose?

My answer is 16/25 of 1ke but while deriving this answer I simply solved based on the question as if the "maximum" in the question didn't exist. But later on I wondered if it has some significance for which I should have applied different method than the general one i.e. using conservation of momentum and energy assuming different final velocities for both the masses.

I also wondered if the answer could be as the neutron 1ke it might lose all of its energy if it comes to a halt but again I doubt that it is possible because helium is not extremely large in mass compared to neutron.

I wanted help to know if there any significance of maximum in the question? I request you to give hint if it does!
 
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  • #2
There is the possibility that the the collision is not "head on".
 
  • #3
TSny said:
There is the possibility that the the collision is not "head on".
Based on your comment I tried to solve assuming that the neutron formed certain angle after the collision and then worked the problem out in center of momentum frame. Finally, I reached a point where I had to choose the scattering angle for minimum final velocity of the neutron, which was the direction opposite to that of its initial velocity. The answer was 16/25 of 1keV.

Do you think the answer is wrong?
 
  • #4
I think 16/25 keV is correct for the maximum loss of KE of the neutron. Your analysis in the center of mass frame is a good way to approach the problem.

This occurs for a head-on collision in which the neutron bounces straight back. If the collision is not head-on, then the neutron would lose less energy. Thus, you have found the maximum KE that the neutron could lose.
 
Last edited:
  • #5
TSny said:
I think 16/25 keV is correct for the maximum loss of KE of the neutron. Your analysis in the center of mass frame is a good way to approach the problem.

This occurs for a head-on collision in which the neutron bounces straight back. If the collision is not head-on, then the neutron would lose less energy. Thus, you have found the maximum KE that the neutron could lose.
Thank you for your help.
 

1. What is the maximum amount of energy a neutron can lose?

The maximum amount of energy a neutron can lose is dependent on its initial energy and the medium through which it is traveling. In a vacuum, a neutron can lose all of its energy through collisions with other particles. In a medium, such as water or lead, a neutron can lose up to 80% of its energy through elastic collisions.

2. How does the maximum amount of energy a neutron can lose affect nuclear reactions?

The maximum amount of energy a neutron can lose is an important factor in nuclear reactions. In fission reactions, neutrons are often used to trigger the splitting of atoms and release energy. The amount of energy the neutron can lose determines how effectively it can trigger the reaction. In fusion reactions, the maximum energy loss of a neutron is important in determining the energy output of the reaction.

3. Can a neutron lose more than its maximum amount of energy?

No, a neutron cannot lose more than its maximum amount of energy. This is because the maximum energy loss is determined by the laws of conservation of energy and momentum. Any additional energy loss would violate these laws.

4. How is the maximum amount of energy a neutron can lose calculated?

The maximum amount of energy a neutron can lose is calculated using the laws of conservation of energy and momentum. The initial energy and mass of the neutron, as well as the properties of the medium it is traveling through, are taken into account in the calculation.

5. How does the maximum amount of energy a neutron can lose change with increasing initial energy?

The maximum amount of energy a neutron can lose increases with increasing initial energy. This is because higher-energy neutrons have a larger range of possible energy states and therefore can lose a larger amount of energy through collisions with particles in a medium. However, at very high energies, the maximum energy loss may decrease due to the effects of relativity.

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