EM behavior when the wavelength is much smaller than the object
James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney in Basic Introduction to Bioelectromagnetics, 2018
In this chapter, we discuss the case where the wavelength of the electromagnetic radiation is much smaller than the size of typical objects. Since details smaller than about 0.3 mm are difficult to resolve with the naked eye, this chapter is concerned with waves whose frequencies are high enough that their wavelengths are smaller than 0.3 mm. Since f = c/λ (Eq. 1.15), this means that the frequency will be in the range of 3 × 108 (m/s)/0.3 × 10−3 (m) = 1 × 1012 (Hz) = 1 THz and higher. The lowest end of this frequency range intersects with the millimeter-wave band, so named because its wavelengths are fractions of a millimeter up to a few millimeters (see Figure 1.31 for a graph of the various electromagnetic regions). At somewhat higher frequencies are the far-infrared waves, then the near-infrared waves whose wavelengths are on the order of micrometers, named far and near according to their relative closeness to visible light wavelengths. Higher in frequency (shorter in wavelength) is the very important visible wavelength range (between 400 and 700 nm), where many significant discoveries and devices such as lasers have been made, undoubtedly due to the significance of light in human vision. At slightly higher frequencies are the ultraviolet (UV) waves. At much higher frequencies are the soft, then hard, X-rays.
Application of Synchrotron Radiation Technology in Marine Biochemistry and Food Science Studies
Se-Kwon Kim in Marine Biochemistry, 2023
This new light source, a soft X-ray, is more than 100 times brighter than a third-generation light source and runs on 5 MW, which is 1/10th that of RIKEN/SPring-8, with an ultra-low emittance and an energy of 3 GeV. A soft X-ray has a high sensitivity for light (low atomic weight) elements, compared with hard X-ray (Tanino et al. 2017). Accordingly, next-generation light sources are suited to the observation of soft materials, such as biological substances and food, for the study of their functions at the nanoscale. This light source represents a cutting-edge technology for the visualization of material function and dynamics and will help establish and accelerate collaboration between industry and academia for the development of SR-based applications using a new concept known as a “coalition concept” (PhoSIC 2019). SR-based technology has the potential to provide innovative and scientific information about ecology, environmental science, resource science, life science, and food science to establish sustainable development goals (Willis et al. 2021; Visbeck et al. 2014; Jacob-John et al. 2021; Thilsted et al. 2016; Farmery et al. 2021; Azra et al. 2021; Galgani et al. 2021; Nakano 2019). In particular, information regarding marine science obtained by SR-based research is likely to improve and enrich our quality of life in the near future. Thus, further investigation on SR-based technology is required to advance our knowledge of the relationship between the application of next-generation SR light sources and marine biochemistry.
Radiation protection in the non-nuclear industry
Alan Martin, Sam Harbison, Karen Beach, Peter Cole in An Introduction to Radiation Protection, 2018
The quality or energy spectrum of X-rays depends amongst other things (including tube filtration and anode material) on the voltage waveform applied to the anode of the tube. If the peak voltage is 200,000 V (or 200 kV), this is expressed as 200 kV peak or 200 kVp. Then the maximum energy of the X-rays produced is 200 keV, but only a very small fraction will have this value and most of the X-ray photons will be in the lower energy part of the X-ray spectrum. The quality of the X-rays is, however, largely defined in terms of this peak energy and they are said to be 200 kVp X-rays. The penetrating power of X-rays is highly dependent on their energy. For example, the quality or ‘hardness’ of X-rays used to radiograph a person's hand would be much too low to radiograph a 10 mm steel plate. The voltage on the tube is therefore set to give the appropriate quality of X-rays for each application. The spectrum of X-ray photons produced by a typical X-ray tube and generator combination is shown in Figure 15.2.
Scanning transmission X-ray microscopy study of subcellular granules in human platelets at the carbon K- and calcium L2,3-edges
Published in Platelets, 2022
Jeonghee Shin, Sehee Park, Tung X. Trinh, Sook Jin Kwon, Jiwon Bae, Hangil Lee, Eugenia Valsami-Jones, Jian Wang, Jaewoo Song, Tae Hyun Yoon
STXM images of the human platelets were acquired at the SM beamline of the Canadian light source (CLS, Saskatoon, Canada). The maximum current of 220 mA at the CLS was operated in the decay mode. The synchrotron-based monochromatic soft X-ray was focused on ~30 nm using a Fresnel zone plate (outermost zone width of 25 nm). The first order of the diffractively focused X-ray was selected using the order-sorting aperture (OSA, pinhole diameter of 50 µm). The sample was mounted on the interferometrically controlled piezo stage and raster-scanned. The intensity of the transmitted X-rays was measured using a scintillator photomultiplier tube (PMT). The STXM images of the whole mounted platelets were collected in an area of 8 µm × 8 µm with 150 × 150 pixels. Energy calibration at the carbon K-edge was performed using the 3p Rydberg peak at 294.96 eV of gaseous CO2 flushed into the STXM chamber. To obtain the carbon K-edge and calcium L2,3-edge XANES spectra, stack images of the platelets were collected in the energy range of 280.0 to 320.0 eV and 340.0 eV to 360.0 eV. The energy positions of the calcium L3-edge and L2-edge main peaks were calibrated to 349.2 eV and 352.5 eV. aXis2000 software [29] (version 11-Oct-2019) was used to calculate the optical density (OD), carbon and calcium distribution maps, and principal component analysis (PCA). The PCA was performed using two methods: Euclidean distance similarity and angle-based similarity.
Mass spectrometry-based phospholipid imaging: methods and findings
Published in Expert Review of Proteomics, 2020
Al Mamun, Ariful Islam, Fumihiro Eto, Tomohito Sato, Tomoaki Kahyo, Mitsutoshi Setou
In biology, imaging refers to the techniques used to visualize internal structure or biomolecules in tissues and cells of a living system, in two-dimensional (2D) or three-dimensional (3D) style without perturbing the structure. The history of imaging dates back to 1895 when Wilhelm Roentgen discovered X-ray. X-ray was originally used in medical imaging to create a 2D image of internal organs in an X-ray film [1]. With the advancement of computer vision and algorithms, several methods such as computed tomography [2], magnetic resonance imaging [3], positron emission tomography [4], and ultrasound [5] have been evolved to produce 2D as well as 3D image [6]. Besides anatomical imaging, those techniques play important role in molecular imaging where contrast agents are used for the noninvasive visualization, characterization, and measurement of the biological processes in the living system [6–8]. Discovery of electron microscope enabled the comprehensive visualization of cellular and subcellular ultrastructures [9]. Some other microscopy-based labeled molecular imaging techniques such as green fluorescent protein labeling [10], and immunohistochemistry [11] are used to visualize the distribution map of protein molecules in tissue as well as cell structure.
Development of a navigable 3D virtual model of temporal bone anatomy
Published in Journal of Visual Communication in Medicine, 2023
A CT or CAT (Computer Axial Tomography) scan, is a non-invasive diagnostic imaging test which uses modified x-ray technology to generate cross-sectional images of the body or a body part from different positions. It involves selective exposure of the patient to radiation. This data is then used to create detailed images of internal organs, bones, soft tissues, and blood vessels. CT scans help identify any tumours, blood clots, fractures, or other abnormalities that are indicative of trauma or any underlying pathology. A narrow X-ray beam circles around and selectively penetrates the part of the body being inspected. Instead of a film, the X-rays are picked up by special detectors, that are located directly opposite to the x-ray source, and transmitted to a computer (Brennan 2010). The computer uses sophisticated mathematical algorithms to assemble 2D cross-sectional images or slices. Recent growth in software technology has enabled us to easily construct 3D volumes from 2D CT images. 3D CT allows simultaneous navigation in all three planes, thereby providing greater flexibility than conventional planar X-rays (Fatterpekar et al. 2006). It is currently used in areas such as trauma, tumours, and craniofacial deformities, to simulate the morphology of body parts.
Related Knowledge Centers
- Fluorescence
- Fluoroscopy
- Gamma Ray
- Ionization
- Radiant Energy
- Ultraviolet
- Bone Fracture
- Medical Diagnosis
- Crookes Tube
- Photographic Plate