Bragg–Gray cavity theory
Imagine you are playing with toys and you have a big, round ball that you want to measure how heavy it is. But you can't see through the ball so you can't just look at the weight. What do you do? You could use a trick called the Bragg-Gray cavity theory.
The first thing you need to know is that everything is made up of tiny pieces called atoms. These atoms have a center called a nucleus that is surrounded by electrons. When something is heavy, it means there are more atoms packed together. When something has radiation inside of it, it means there are tiny particles called photons that can move through things like light can move through glass.
Now, let's say we put our big, round toy ball inside a tiny box with a window in it. We then shoot a beam of radiation at the box and the ball so that it goes through the window and hits the ball. But as it passes through the ball, some of the radiation will bounce off the atoms inside the ball, kind of like a ball bouncing off a wall.
This bouncing off process changes the radiation and makes it weaker. To measure this change, the Bragg-Gray cavity theory says that we can place a tiny detector inside the box with the ball. This detector is called a cavity and it is like a little room that traps some of the radiation. How much radiation gets trapped in the cavity depends on how much the radiation changed when it bounced off the atoms in the ball.
So by measuring how much radiation is trapped inside the cavity, we can figure out how heavy the ball is because the heavier the ball, the more atoms it has, and the more radiation will bounce off of those atoms, making the radiation weaker and therefore trapping more in the cavity.
And, that's the Bragg-Gray cavity theory!
The first thing you need to know is that everything is made up of tiny pieces called atoms. These atoms have a center called a nucleus that is surrounded by electrons. When something is heavy, it means there are more atoms packed together. When something has radiation inside of it, it means there are tiny particles called photons that can move through things like light can move through glass.
Now, let's say we put our big, round toy ball inside a tiny box with a window in it. We then shoot a beam of radiation at the box and the ball so that it goes through the window and hits the ball. But as it passes through the ball, some of the radiation will bounce off the atoms inside the ball, kind of like a ball bouncing off a wall.
This bouncing off process changes the radiation and makes it weaker. To measure this change, the Bragg-Gray cavity theory says that we can place a tiny detector inside the box with the ball. This detector is called a cavity and it is like a little room that traps some of the radiation. How much radiation gets trapped in the cavity depends on how much the radiation changed when it bounced off the atoms in the ball.
So by measuring how much radiation is trapped inside the cavity, we can figure out how heavy the ball is because the heavier the ball, the more atoms it has, and the more radiation will bounce off of those atoms, making the radiation weaker and therefore trapping more in the cavity.
And, that's the Bragg-Gray cavity theory!