Stationary Target X-Ray Tubes - Energy

In summary, an x-ray tube with a stationary target operated at a constant voltage and current of 100kV and 50mA for 0.2s will deposit approximately 1000J of energy, but it is not possible to accurately determine how much will be emitted as heat and how much as x-rays. However, an estimate from lecture notes suggests that only about 1% of the energy will be emitted as x-rays, which would equate to 10J, leaving 990J as heat.
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ChrisJ
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Homework Statement


An x-ray tube with a stationary target is operated with a constant voltage and current of 100kV and 50mA for 0.2s . Approximately how much energy will be deposited as heat in the target and how much emitted as x-rays?

Homework Equations


##P=IV## ?

The Attempt at a Solution


This is not coursework but preparation for an exam, it is is a past paper question.

I'm just a bit confused really as I can't find any reference to how to calculate the amount as heat/x-rays etc.

But the Energy in 1/5s would just be
[itex]
P=IV=(50 \times 10^{-3})(1 \times 10^5)=5000[/itex] W
So therefore in 1/5s of a second the energy would be 1000J.

But how do I work out how much of that is heat or x-rays? Is that even correct as it? The only reference to anything at all relating to this in the lecture notes/slides says that usually only around 1% is x-rays, so I don't know if the question just wants me to say that and therefore say ~10J as x-rays and 990J as heat?
 
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  • #2
ChrisJ said:
The only reference to anything at all relating to this in the lecture notes/slides says that usually only around 1% is x-rays

i think the quoted estimate of 1% of energy being emitted as X-rays is an operational figure and the details of the estimate can not be done with the available data.
There are formulae for estimating the continuous X-ray intensity and it is proportional to Z the atomic number, tube current and square of the Potential difference applied.about one percent of the KE of electrons are used up in producing X-rays.
 
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1. What is a stationary target x-ray tube?

A stationary target x-ray tube is a device used in medical imaging to produce x-rays. It consists of a cathode (negative electrode) and an anode (positive electrode) separated by a vacuum. When high voltage is applied to the cathode, electrons are emitted and accelerated towards the anode, producing x-rays.

2. How does a stationary target x-ray tube produce energy?

A stationary target x-ray tube produces energy by converting electrical energy into x-ray energy. When the accelerated electrons hit the anode, they interact with the metal atoms, causing the release of x-rays. The energy of the x-rays produced is determined by the voltage applied to the tube.

3. What is the difference between the energy produced by a stationary target x-ray tube and a rotating target x-ray tube?

The main difference is in the way the x-rays are produced. In a stationary target x-ray tube, the electrons hit a fixed anode, while in a rotating target x-ray tube, the electrons hit a rotating anode. This allows for a larger target area in the rotating anode, leading to higher energy x-rays and longer exposure times.

4. What factors can affect the energy produced by a stationary target x-ray tube?

The energy produced by a stationary target x-ray tube can be affected by several factors, including the voltage applied to the tube, the type of material used for the anode, and the size and shape of the anode target. The distance between the cathode and anode can also affect the energy produced.

5. What are the advantages of using a stationary target x-ray tube over a rotating target x-ray tube?

One advantage is that stationary target x-ray tubes are typically less expensive and easier to maintain than rotating target x-ray tubes. They also have a longer lifespan and can produce high-quality images at lower energy levels. However, rotating target x-ray tubes are better suited for certain types of imaging, such as high-resolution imaging and procedures that require longer exposure times.

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