Experiment 1
Introduction:
The aim of this experiment is to investigate the effect of the inverse square law on a beam of x-ray photons. The inverse square law states that the intensity of an x-ray beam is inversely proportional to the square of the distance (Ball, J.L., Moore, A.D. and Turner, S., 2008). Similar triangles (Appendix A- Image 1) are a proof of the inverse square law as it shows that if the distance from the beam is doubled, the intensity falls to one-quarter of its original value. If it is trebled the intensity falls to one-ninth and at four times the distance it is one-sixteenth its value, etc (Holmes, K., Elkington, M. and Harris P., 2013). The formula used to calculate this is:
This law only applies if the radiation is from a point source, the radiation of the beam is homogenous (the photons must all have the same energy) and if there is no attenuation between the source of radiation and the detector (Holmes, K., Elkington, M. and Harris P., 2013). However, the x-ray beam cannot satisfy these three conditions of the inverse square law. This is because the x-rays produced are not emitted from a true point source as the focal spot has a finite size. They are not emitted equally in all directions as the anode heel effect causes the intensity to vary across the beam and the absorption and scattering of the x-ray beam occur as it passes through the air (Graham, D., Cloke, P. and Vosper, M., 2012). Despite this, the inverse square law can still be applied
X-rays have numerous different effects on the tissues of the body, depending on the time of exposure and energy of the X-ray photons. Best contrast between different tissues is when the photon energy is about 30 keV, for diagnostic purposes. Resulting in the photoelectric effect dominating at this energy. The tissues absorb X-rays and electrons are released. The X-ray absorption depends on the number of protons in the nuclei of the atoms encountered. A high number will attenuate the beam, producing a strong x-ray shadow, enabling for a high quality image of
A scientist would need a glass tube with positive and negative electrodes. The tubes were called cathode tubes, and they were common in the late 1890s. The air leaves the glass tube, and a florescent glow is produced when a high voltage runs through the tube. The scientist needs to cover the glowing tube with a heavy, black paper or cardboard. Then the scientist will see the green colored fluorescent light illuminating from the box. This is known as the X-Rays which energizes the phosphorescent materials in the room. The newly discovered ray would pass through objects, and it can cast a shadow of most solid objects. The ray consists of electron passing through the matter underneath the cathode tube. It can pass through human tissues, but it cannot pass through bones and metal
Radiologic technologists, or x-ray techs, are medical professionals who take radiographic pictures of bones. They are assistants to radiologists; the x-ray techs take the pictures and the radiologists examine the x-ray and diagnose what is wrong with the patient. “They are educated in anatomy, patient positioning, examination techniques, equipment protocols, radiation safety, radiation protection and basic patient care” (American Society of Radiologic Technologists, 2017). It is crucial that x-ray techs be exact and precise or else the pictures will be incomprehensible, thus making it nearly futile for the radiologist to interpret them.
Graph the number of photons emitted relative to the black square. That is, graph the black square as 100 percent, and the other squares relative to this standard.
In the last decades the management of patients with uveal melanoma has changed towards globe sparing techniques. Alternatives to the radical enucleation vary from observation to transpupillary thermotherapy, block-excision, and endoresection with pars plana vitrectomy, brachytherapy using a variety of radioisotopes, radiotherapy, Leksell Gama Knife and stereotactic radiosurgery (Henderson et al. 2006; Dieckmann et al. 2006; Mosci et al. 2009).
After receiving the document, Yagoda already noticed uneasiness whether the title should be hyphenated or not. However, Yagoda’s explored and delved into grammar rules for the word written differently “x ray,” “x-ray,” “X-ray” and “X ray.” The life of the word “x ray” started on November 8, 1895 when Wilhelm Conrad Röntgen coined the name “X-Strahlen” for his discovery of radiation. The New York Times translated the word as X-rays in 1896, clarifies Yagoda. Shortly after introducing the word, the New York Times wrote the word without a hyphen, although the newspaper gradually returned hyphen in 1920s. Yagoda wrote to the author of the document who replied on the practice in the physics community to write “x ray” when referring to the radiation we call “x.” It existed as an illustration that even physicists could not spot the various nuance. He also indicated “editors convert all spellings ‘x ray’ to ‘x-ray’ or to ‘X-ray.’” For Yagoda, that was the point when he “experience temptations of homicide,” and when the two
X-ray equipment safety requirements are essential and are part of improving the technical side of medical imaging with the goal of protecting the public and imaging professionals in the field. In order for x-ray equipment to be up to date and performing at a quality level, certain test, individuals, and standards are set to meet these
PURPOSE: The aim of the investigation was to further our understanding of the physical laws that govern our ability to receive and interpret information in the form of visible light. We have all had a physics class that at least brushed the introduction of optics, but we can still further our comprehension by experimenting with optics that have different characteristics. Does one axis truly get inverted when viewing an object through a lens? How significant of an effect does human error have in calculating reflection (if any)? How much does magnification blur an image viewed through an optic? How much does the angle of light deflect from a change of medium?
The X-Ray was invented in 1895 by Wilhelm Conrad Roentgen. It all started with a vacuum tube called a Crookes tube, with this Roentgen noticed that by pressing a button that activated an electric current through it a shadow was projected onto a screen that showed the photograph of his wife’s hand with a ring
During the cold winter of 1895, a German scientist by the name of Wilhelm Conrad Roentgen was working with a cathode-ray tube when he noticed nearby crystals were glowing. When Roentgen reached for the crystals he was amazed when the shadow cast on the crystal was not of his whole hand, but just his bones. Roentgen covered the tube with heavy black paper and saw that the crystals still glowed and the shadow of his hand bones still shown through, he then determined that a new ray was being emitted that could penetrate through thick materials. (1.) He later found that the rays could pass through most anything, but would cast a shadow of solid objects; these shadows could then be captured on film. Among the solid objects Roentgen shot with
As the field size is decreased there is an increase in the lateral electronic equilibrium, thus less dose is deposited on the CAX. This results in a drop of the measured ROFs as seen in the acquired data. The sharpness of the drop is energy dependent, i.e. the higher the energy the sharper the drop. This was shown by the data as it was seen that the 15MV photon beam has a higher ROF until 3cm field size, from there on the ROF dropped sharply to having the same or similar ROF at the 1cm field for all the photon
Geiger was joined by Ernest Marsden to create a new instrument to detect whether alpha particles could be deflected at greater angles. This device was different from the previous in the way that the gold foil and radium were both inside a metal cylinder, which was fixed to a swivel. The microscope attached penetrated the wall of the cylinder. The lens of the microscope was covered in a zinc sulphide screen and the microscope could be moved in a full circle around the foil so Geiger could tally the flashes of light from every possible angle. He observed alpha particles deflecting by as much as 150°.
X-rays were discovered by accident in 1895 by the German physicist Wilhelm Conrad Roentgen. Roentgen was already an accomplished scientist with forty-eight published papers. He had a reputation among the scientific community as a dedicated scientist with precise experimental methods. Roentgen had been conducting experiments at the University of Wurzburg on the effect of cathode-rays on the luminescence of certain chemicals. Roentgen had placed a cathode-ray tube, which is a partially evacuated glass tube with metal electrodes at each end, in a black cardboard box in his darkened laboratory. He sent electricity through the cathodre-ray tube and noticed something strange his laboratory. He saw a flash of light
However, the relationship between intensity and voltage is a little more complex. When the voltage is higher than the excitation voltage Vk, the higher the voltage, the larger the intensity. The detailed relationship is that the intensity is linearly proportional to the 1.5 power of the difference between the real voltage and Vk. This effect is similar over the entire X-ray spectrum when there is valid intensity. When the voltage is larger than Vk, the corresponded λ is larger than λswl, this effect works.
X-ray tube is designed to lower the amount of heat produce, this can be accomplished by the rotating of the anode which gives off heat. The X-ray tube is designed with the anode attach to the rotor and cathode on the other side of anode. This design determines the characteristics of X-ray beam.