What is Neutron Scanning?

As you are aware, I have been obsessed with neutrons for a while.

I didn't feel comfortable talking about neutrons, the articles were all theoretical and about neutrons in space, and I wondered if these neutrons have some practical benefits.

So I opened the internet and I thought I would look into the neutron issue a little more.

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But unfortunately, I realized that before we go directly into the practical benefits of neutrons, we need to go a little bit more theoretical.

I don't want to confuse you too much, but it seems to me that without this information it is not possible to understand what we can do with neutrons in practice.

So I say a little more patience and I would like to give a little more information about neutrons.

First, let's remember what the physical properties of neutrons are. 

Neutrons are electrically uncharged subatomic particles, and since they have magnetic momentum, they are affected by magnetic fields.

They are essentially a combination of a proton and an electron with (positive) beta decay.

But since this is not possible on Earth, if we want to obtain neutrons, we need to utilize the neutrons already present in the elements.

However, it is not easy to extract the neutron from the nucleus of every element. 

There are ready-made radioactive elements, but they do not release free neutrons into the environment when they emit radioactive radiation.

More than radioactive elements:

1. An alpha particle is released by what we call alpha radiation, which is the nucleus of the helium atom. The nucleus of the helium atom, which consists of two protons and two neutrons, but no electrons.

2. Or there is what we call beta radiation, which you may remember from my previous articles, which emits electrons. Of course, in addition to this elementary particle, the elementary particle we call the opposite neutrino is also emitted in this radiation. Because this radiation, whose source is minus beta decay, is formed by the decay of excess neutrons in the nucleus. In this radiation, an excess neutron in the nucleus turns into a proton and the radioactive element turns into another element and the electron released radiates. The electron that escapes from the nucleus with high energy cannot stay in orbit around the nucleus and radiates.

3. There is also gamma radiation, but gamma radiation only means that the excess energy in the nucleus of the radioactive material is released in energy packets. So there is no change in the nucleus in gamma radiation. But because gamma radiation is a very high energy radiation, it has the danger of disintegrating everything in its path.

These are radiations that a radioactive element can make on its own.

We need neutron radiation.

Yes, you can get neutron radiation from radioactive materials, but only from an external influence.

4. So we can think of neutron radiation as the fourth type of nuclear radiation. There are isotopes of various elements that spontaneously emit neutrons. However, I know that it is not possible to use isotopes of elements for neutron production because the lifetimes of these isotopes are quite low.

One of the most commonly used methods for neutron production is to apply alpha radiation to the Beryllium atom (Be, an element with atomic number 4 and mass number 9, that is, an element with 4 protons and 5 neutrons in its nucleus). 

By the way, beryllium is not a radioactive element!

Since the alpha particle is the nucleus of my helium atom, it is a radiation of 2 protons and 2 neutrons, and radioactive elements release these particles as they decay (this decay is called half-life!). Finding alpha particles is dangerous but relatively easy. 

Here, when the nuclei of helium atoms with 2 protons and Beryllium atoms with 4 protons are bombarded, a carbon atom with 6 protons emerges. 

You know that a stable carbon atom has 6 neutrons in its nucleus. So a normal carbon atom has a mass number of 12 in the periodic table. Of course, carbon has isotopes like many other elements. Carbon 14 is one of them. But in the stable state, the carbon atom is known as carbon 12.

In this process, we have 7 neutrons, two from the alpha particle and 5 from the beryllium atom.

In this case, as a result of the bombardment, one neutron is wasted and the beryllium element radiates neutrons while turning into carbon.

He + Be => C + n

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Another method of obtaining neutrons is one that does not require radioactive elements to begin with.  

This one uses the element mercury to produce neutrons.

This time, positively charged protons are bombarded with mercury atoms, and when they break apart, they release neutron beams.

The protons used in this method, also called the Spallation Neutron Source (SNK) method, are positively charged hydrogen ions. 

The ion, the electron-depleted hydrogen atom, is the source of the protons used in this process.

The protons are accelerated in an electric field to bombard the mercury nucleus (Hg, atomic number 80), which is a widely used method.

This method, which also produces gamma radiation with very high energy, is known as one of the preferred methods for neutron production.

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Yes, I think everything is normal so far, we can say that somehow we got neutrons according to our preferred method. 

But what are we going to do with these neutrons if we want a practical benefit?

Since neutrons are affected by magnetic fields even though they have no electric charge, it is now possible to accelerate or decelerate neutrons with magnetic fields.

Since neutrons are electrically uncharged particles, they can reach the nuclei of atoms and penetrate very deep and thick layers of various materials.

In this way, it is possible to reach much deeper than X-rays (X-rays) obtained by electron bombardment and, more importantly, to determine the internal structure of something in three dimensions with neutron radiation. 

Moreover, the different types of materials in which the thing being looked into is composed can be transferred to the computer environment and converted into color screen images.

X-rays (X-rays) are also very high-energy rays, but neutron radiation can reach much deeper into matter. This makes it possible to examine much larger things.

For example, with this method, called neutron scanning, a fossil stone from ancient times can be examined without breaking it. 

If there are animal bones or animal teeth in the stone, for example, a three-dimensional image of these bones can be transferred to a computer without breaking the stone. 

Then the necessary scientific studies can be carried out.

This method is considered a revolution in the scientific world.

Moreover, since the speed of the neutron beam in motion is slowed down considerably in these devices, the neutrons have no harmful effect on the nuclei of the fossil's atoms at the atomic level.

Normally, the speed of neutrons emitted from the source is quite harmful from a biological point of view.

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At this stage, let me briefly mention the effects of neutrons on the atomic nucleus.

Depending on the speed of the neutron beam, neutron radiation can actually be quite dangerous.

Atomic bombs, as you know, are bombarded with neutrons, which causes the uranium atom to disintegrate and thus create the effect of a bomb. After this first fragmentation, the chain nuclear reaction starts!

But if the neutron beam is slowed down enough, when it hits the nucleus, it can continue on its way, like a billiard ball, transferring only momentum to the nucleus. 

Of course, its direction changes in this collision, and already in neutron scanning, the internal structure of matter can be detected with neutrons slowed down in this way. The shape created by the neutrons reaching the sensors directly and the reflected neutrons provides three-dimensional images of the materials under investigation.

If the speed of the neutrons is slightly higher, they can cause alpha, beta or gamma radiation in the atomic nucleus, depending on the material hit. 

A slightly faster neutron beam, for example, can penetrate into the nucleus of a substance and cause the formation of an isotope of that element. 

An isotope, as you know, is an element that has the same number of protons in its nucleus, but a different number of neutrons and a different atomic weight. A little bit above I mentioned the carbon 14 isotope of the carbon atom.

When there is a slightly faster neutron beam, when it hits the nucleus, it can take a neutron from the nucleus and replace that neutron. In this case, we can say that the substance is radiating neutrons.

An even faster bombardment of neutrons would shatter the nucleus, as in atomic bombs. 

If the atom whose nucleus is shattered is a uranium atom, the additional neutrons released during the shattering initiate a chain reaction and the result is an atomic bomb explosion!

In other words, neutron scanning devices have very sensitive settings. The speed of the neutrons must be reduced to such an extent that they do not damage the atomic nuclei of the substances under investigation. Otherwise, neutron radiation is a very dangerous type of radiation.

Nevertheless, I can say that neutron scanning devices have started to enter our lives because they can scan as a higher technology than the x-ray scanning we are used to with x-rays. 

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I don't know if neutron scanners have started to be used in our airports or hospitals, but these devices have started to be used in airports abroad, especially for scanning large-sized cargo.

I think that this new scanning method, which is very useful, should be used in our country if it is not already in use.

X-ray scanners are probably useful for small-sized luggage, but I know that x-ray scanners are not very useful for larger-sized cargo. 

If the issue is security, I think it is necessary to examine the cargo with neutron scanners that scan more in depth.

In videos on the internet, they even mention that they can scan the entire car at customs gates, even when passing by car.

The same thing can be used to scan yachts at the entrances of marinas.

So neutron scanners now have applications around the world.

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Now that I think about it, a possible construction application just came to my mind.

We mostly use sonar scans (sound scanning!)

Instead of sonar scanning, buildings can also be scanned with neutron scanners in terms of earthquake resistance, and thanks to its coloring feature, the bars, beams and columns in the carrier system of the existing building can be transferred to the computer in three dimensions with their dimensions and the calculation can be made again according to the new regulations.

I think whether the building is earthquake resistant or not can be easily determined in this way without any damage to the building.

Since cracks, if any, can be detected much more easily after the earthquake, this method can also be used for the detection of building damage after the earthquake.

I think it is useful for my colleagues to examine this issue. It is both a harmless method of examination and I think it is not such a costly method.

Maybe these devices have actually been applied in construction. I have not come across it, but someone may have really thought about this.

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I think that concludes the neutron issue. 

I don't know if there are other practical uses for neutrons, but I think in principle these scanners have the potential to replace X-ray and MRI devices in medicine.

Maybe they could also be used in place of ultrasound devices. 

But the speed of the neutron beams would have to be reduced to a level that would not harm human health.

Perhaps, if this is possible, X-ray machines may even become a thing of the past. 

Because the human body can only accept a certain amount of x-rays, and although x-rays are not directly radioactive, they pose a cancer risk, especially when exposed to too much of them, as they can break the DNA chain in our cells.

In fact, in foreign countries, everyone has special x-ray record books in hospitals where the doctor keeps a record. I don't know if we have them here.

As far as I know, even dental x-rays are dangerous for health after a certain degree.

Also, speaking of cancer, maybe chemotherapy can one day be replaced by neutron therapy and neutron radiation can be used in cancer treatment.

These are the practical applications I can think of.

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Yes, let me end this article by saying stay with science again.

I am also looking at other science topics, I hope this kind of articles are useful.

Love and respect to everyone from Moscow.