X-ray tube voltage is the voltage applied to the X-ray tube. In an X-ray tube, a high-voltage power supply is connected between the cathode and anode. The high voltage accelerates electrons generated from the cathode to collide with the anode, generating X-rays. Higher X-ray tube voltage produces X-rays with shorter wavelengths, which penetrate materials more easily.
For example, the shortest wavelength X-ray generated from an X-ray tube voltage of 100 kV, the maximum energy X-ray generated from an acceleration of 100 kV is 100 keV, so the formula using Planck's constant E = hν = hc/λ [ J ] gives 1.24/100 keV = 0.0124 nm (0.124Å).
Another feature is that X-ray tubes generate total intensity X-rays that are proportional to the square of the tube voltage.
For more information on X-ray tube voltage and transmission power, please refer to the Q&A section "What is the tube voltage or acceleration voltage necessary for X-ray inspection systems?".
X-ray Tube Current
X-ray tube current is the current flowing through the X-ray tube. Thermo electrons generated by the X-ray tube filament collide with the anode, resulting in an electric current. The total intensity of the X-rays is proportional to the X-ray tube current. Increasing the X-ray tube current increases the x-ray dose. However, the shortest wavelength (maximum energy) remains the same. The filament current (filament temperature) controls the X-ray tube current.
Focal Spot Size
The focal spot size is the size of the area where electrons collide with the anode of the X-ray tube to produce X-rays. It is not necessary to be very sensitive to the focus size for medical or analytical X-ray tubes. However, for magnified observation of small parts, selecting an X-ray tube with a microfocus size is required.
For details, see the technical column "What is Microfocus X-ray (Basic Knowledge)" and the technical tips "X-ray Nondestructive Inspection Series (1) X-ray CT How to take a clean image?". Please refer to the "X-ray focus".
FID stands for focus-to-image receptor distance, which is the distance from the X-ray focus to the imaging device. The imaging device is often an X-ray camera called an FPD, which allows real-time observation of X-ray images.
FOD stands for focus-to-object distance, which is the distance from the X-ray focal point to the projected sample (object).
Geometric magnification is the ratio of the actual size of the sample to the size of the X-ray image projected on the X-ray camera. This value is the ratio of the distance from the X-ray focal point to the object (FOD) to the distance from the X-ray focal point to the camera (FID).
For example, if an object is placed 100 mm away from the X-ray focus and a camera is placed 400 mm away from it, geometric magnification = FID/FOD = (100+400)/ 100 = 5 [times].
Placing the camera farther away increases the geometric magnification, but reduces the amount of X-rays incident on the camera. To increase the geometric magnification, shorten the FOD (move the object as close to the X-ray tube as possible) to obtain a large geometric magnification.
Monitor magnification is the magnification ratio of the X-ray image taken and displayed on a computer monitor. This magnification also includes geometric magnification. Today, this is not important because images can be imported and displayed on a computer and easily scaled.
Controlled Radiation Area
Japan's Ordinance defines a controlled radiation area for Prevention of Ionizing Radiation Hazards as an area where the dose may exceed 1.3 millisieverts per three months. It also stipulates that this controlled area must be clearly marked by signs.
In Matsusada Precision's X-ray inspection system, the internal X-ray irradiation area is a controlled area.
For more information, see Q&A, "Is a license required for usage of X-ray inspection system?".
Radiation Leakage Dose
Radiation leakage dose is the amount of X-rays leaked outside the X-ray equipment. The leakage doses of our X-ray inspection systems are all less than one μSv/h. Periodic leakage dose inspections are recommended to prevent exposure to the user of the X-ray equipment and those around him or her. We measure the leakage dose with a highly sensitive survey meter.
Region Of Interrest (ROI)
ROI stands for Region of Interest. It is a range designation used when image processing is applied to a specific area.
RAW refers to an unprocessed image file format. X-ray flat panel detectors and digital SLR cameras provide image data with a higher dynamic range than the shading displayed on a monitor. Save the image as a RAW file to preserve this data.
TIFF stands for Tag Image File Format and is a type of image format. Since it is uncompressed, You can save images with high image quality.
DICOM (Digital Imaging and Communications in Medicine) is a general-purpose image format and communication standard used in medical imaging equipment. Medical CT, MRI, CR, endoscopy, and ultrasound imaging equipment follow this standard.