How do you cool x-ray tubes?
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How do you cool x-ray tubes?
The anodes in most radiographic equipment are cooled by the natural radiation of heat to the surrounding tube enclosures. However, anodes in some high powered equipment, such as that used in CT, are cooled by the circulation of oil through the anode to a heat exchanger (radiator).
What can you do to help avoid thermal damage to X-ray tubes?
Damage to the x-ray tube can be reduced by:
- not rotating the tube housing rapidly when the rotor is turning.
- making sure exposures are safe by checking a radiographic rating chart.
- turning off the main power supply each night.
- gradually warming up the tube after an extended period of inacticity.
How does the X-ray tube dissipate heat?
The X-ray tube A small increase in the filament voltage (1) results in a large increase in tube current (2), which accelerates high speed electrons from the very high temperature filament negative cathode (3) within a vacuum, towards a positive tungsten target anode (4). This anode rotates to dissipate heat generated.
Why do we need cooling in x-ray tube?
Only a small portion of the energy generated by the system is emitted as X-rays, the balance is released as heat. X-ray systems have a heat load range of 1~5KW that must be efficiently dissipated. The X-ray tube, and specifically the anode, must be cooled for optimized X-ray performance and a longer operation life.
How do you heat an x-ray tube?
Typical warm-up exposure settings use low kVp (60-70), and a long exposure time (1-5 seconds). One warm-up exposure should be made using a small focal spot (50, 100, 150, 200, or 300 mA), and a second exposure should be made using a large focal spot (400, 500, 600, 700, or more).
What exposure controls contrast?
The density can be defined as the photographic effect producing different degree of blackness on the film measured by light absorption through it. The factor that controls contrast is said to be KV and the factor that controls density is termed as mAs i.e. the product of milliampere and the duration of exposure.
Why Molybdenum is used in mammography?
Molybdenum is also often used as the target material for anodes used in mammography because it has an intermediate atomic number (Z=42) and the produced characteristic x-rays are of energies suited for this purpose.
Why is heat produced in Xray production?
X-rays are produced due to sudden deceleration of fast-moving electrons when they collide and interact with the target anode. In this process of deceleration, more than 99\% of the electron energy is converted into heat and less than 1\% of energy is converted into x-rays.
Which controls the penetrating power of the X-ray beam?
The beam quality is controlled by the kilovoltage. The kVp regulates the speed of electrons traveling from the cathode to the anode and determines the penetrating ability of the x-ray beam.