X Ray Production And Interaction With Matter Engineering Essay

X Ray Production And Interaction With Matter Engineering Essay The x-ray tube is the most important part of the x-ray machine because the tube is where the x-rays are actually produced. The production of x-rays requires a rapidly moving stream of electrons that are suddenly decelerated or stopped. (C., Andy, 2008). Basically this means that when fast-moving electrons slam into a metal object x-rays are produced. (Bushong, 2008, Ch.6 p.101). Inside of the x-ray tube are three main factors that play important roles in x-ray production: 1.) The cathode 2.) The anode 3.) The vacuum The cathode and anode are basically the only components that help in the production of x-rays. The cathode or also known as the fast-moving electrons is a negatively charged electrode that contains a focusing cup and a filament. The focusing cup is made of nickel or molybdenum and nearly surrounds the filament. It is open at one end to allow electrons to flow freely across the tube from the cathode to the anode. (Fauber, 2009, p.15). It has a negative charge, which keeps the electrons emitted from the filament spreading apart. The focusing cups purpose is to focus the stream of fast-moving electrons. The filament is coil of wire (about 2mm diameter and 1 to 2cm long) that emits the electrons when it is heated. When the current through the filament is sufficiently high, the outer-shell electrons of the filament atoms are boiled off and ejected. (Bushong, 2008, Ch.7 p.122). This is also referred to as thermionic emission. The Anode The positively charged electrode of the tube is called the anode. It consists of a stator, rotor, and a target. The stator is an electric motor that turns the rotor at very high speeds. These speeds range from 3,000 to 10,000 revolutions per minute (RPM). The rotor is rigidly connected to the target through the anode stem, causing the target to rotate rapidly during x-ray production. High Strength ball bearings in the rotor allow it to rotate smoothly at high speeds. (Fauber, 2009, p.17). The last component of the anode is the target. The target is the metal object that is struck by the focused stream of electrons coming from the cathode. The target then stops the fast-moving electrons and thus creates the opportunity for the production of x-rays. (Nave, 2006, http://hyperphysics.phyastr.gsu.edu/Hbase/quantum/xtube.html) The Vacuum Another contributing factor called a vacuum, which allows for more efficient x-ray production and longer tube life. However, if there is just a little gas is inside the tube, the electron flow from the cathode to the anode is reduced, fewer x-rays are produced, and more heat is generated. If there is too much gas, x-ray production falls and the tube can fail. (Bushong, 2008, Ch.7 p.122). This is why the radiographer needs to be aware of the amount of heat that is produced during x-ray production because excessive heat can damage the tube: and without the tube x-ray production cannot be created. X-ray Interaction with Matter If x-ray production falls, then x-rays cannot interact with matter. X-ray production and x-ray interaction with matter help to form an image. X-rays interact with matter in five different characteristics: 1.) Coherent Scattering 2.) Compton Effect 3.) Photoelectric Effect 4.) Pair Production 5.) Photodistegration Only the Compton effect and the photoelectric effect are important in the process of creating an x-ray image. Coherent Scattering Coherent scattering is an interaction with low energy x-rays, below the diagnostic range. The incoming photon interacts with the atom causing it to become excited. Fauber (2009, Ch.3 p.49) has suggested that the x-ray doesnt lose energy, but changes direction. Coherent scattering contributes very little to the x-ray image, and only a few percent undergo this type of scatter. Coherent scatter contributes slightly to the deterioration of the image, often referred to as image noise, the general graying of an image that reduces image contrast. Most coherent scattered x-rays are emitted in a forward direction. Coherent scattering is a small importance to creating an x-ray image. However, if these scattered photons are absorbed within the tissue, they do contribute to the radiation exposure to the patient. Compton Effect The Compton effect can occur in all x-ray energies and are very important interaction with matter. When scattered x-rays interact with an outer-shell electron, the electron is thrown or ejected from the atom and the atom becomes ionized. The electron that was ejected is called a secondary electron. With the secondary electron ejected the x-ray scatter continues in a different direction with less energy then it started out with. During a Compton interaction the scattered x-ray and secondary electron have divided the energy between them, but usually the scattered x-ray maintains most of it. Eventually both lose all their energy and the scattered x-ray is absorbed photo electrically, while the secondary electron loses all of its energy through ionization and then falls into a vacancy in the electron shell created by a previous ionizing event. The purpose of the Compton effect is to reduce as much contrast on the x-ray image. Photoelectric Effect The photoelectric effect takes place when the incident x-ray is not scattered, but is totally absorbed during the ionization of an inner-shell electron. The incident photon disappears, and the k-shell electron; called a photoelectron is ejected from the atom. The x-ray image results from the difference between those x-rays that are absorbed by photoelectric interaction and those x-rays that are absorbed during ionization through the body as image-forming x-rays. Pair production Pair production is explained by Bushong (2008, Ch.10 pg.168) as an incident x-ray that has sufficient energy; it may escape interaction with electrons and come close enough to the nucleus of the atom to be influenced by the strong nuclear force field. This causes the x-ray to disappear between the nuclear field and x-ray, and in its place forms two electrons: a positron (positively charged) and one that is negatively charged. Pair production interacts with matter, but does not occur during x-ray imaging. Photodistegration The last characteristic of x-ray interaction with matter is Photodistegration, although it does not occur is diagnostic radiology. This process by which very high-energy x-rays (approximately reaching above 10 MeV) can escape interaction with electrons and the nuclear electric field, and can be absorbed directly by the nucleus. When this occurs the nucleus is raised to an excited state and instantly emits a nucleon or other nuclear fragments, which are released. (Bushong, 2008, Ch.10 pg169). Conclusion In conclusion x-ray production and x-ray interaction with matter help to create an x-ray image. Without both basic concepts a simple image would not be possible. Two of the three components that make up the inside of an x-ray tube is: the cathode and anode, which are both important factors in x-ray production. Similar to the five ways an x-ray can interact with matter, only two are important to the formation: the Compton effect and the photoelectric effect. X-ray production and x-ray are different in so many ways, also they go hand in hand, but without one the other does not exist and without either diagnostic imaging cannot occur.

Spanish and English Motives for Settling America

AP US History 1 July 2011 In the early fourteenth century, the Americas were home to natives who had lived there for centuries. They had created entire cities for places of worship. These cities were occupied by skilled mathematicians, architects, and astronomers. Thought they did make human sacrifices to their many gods, the natives were able to control their empire and keep it alive at least until the arrival of the European. On the other side of the world, Europeans were looking for opportunities of freedom, land, goods, and most of all riches.There was a high competition for the desired goods of India and China so Europeans began to search for easier routes that would bring them wealth. Spain was the first to discover and claim the Southwest Americas with the historical voyage of Christopher Columbus. Then a couple of years later, had John Cabot claimed the Northeast Americas for England. The Spanish and English differed in motives and benefits from the settlements that they had created in the seventeenth century because of how they treated the natives, colonized, and reasons of leaving Europe. The Spanish were thirsty for riches.Their main reason for leaving Europe was because of God, glory, and gold. Christopher Columbus’s accidental discovery had provided the right opportunity for the Spanish to achieve their goals. The natives welcomed the Spanish into their cities because they thought they were gods. When the Spanish discovered the vast amounts of gold in the area, they decided to conquer the lands and to gain riches and glory. Many natives died from the wars with the Spanish, but what really killed them was disease. Later on as the Spanish colonized southwest America, they brought Christianity to the natives.Missionaries tried to Europeanize the natives. Many Spanish men married native women and had European American children. In New England, the English colonies had different motives. Theirs was religious freedom. At first the natives and the English made peace treaties because of trade and Christianity. But as time passed tensions grew. The English did not intermix with the natives as the Spanish had. The natives were mainly a pestilence that was in the way of land. As with the Spanish, the natives had their populations wiped out because of European diseases and wars.The natives were forced to combine with other tribes and move to the Midwest. The Spanish settled the southwest Americas and the Caribbean. In the New Mexico and Texas areas of present day America, they found little success in their search for gold. They found the Caribbean useful for the crop plantations of tobacco, sugar, and corn. The Spanish spread Christianity to the natives, built forts and missions, and claimed the land for Spain for centuries to come. The Spanish planted their teachings, language, laws, and religion into their colonies and native neighbors.New England had been settled for the land and freedom it offered. Thousands of miles away from England, the Europeans were able to find comfort in freedom of religion. As colonies grew, things started to change. The colonist both fought with each other over land and religion. Government was made up and some of these written laws were placed in today’s constitution. Major cash crops were grown and the colonies grew also. Africans were shipped to New England as slaves to help maintain these large farms. New Englanders started out on a difficult journey but life continued to get better as the colonies grew.The Spanish and English both wanted to find easier routes to the Indies. They wanted the spices and other luxury goods the Asia had to offer. There were high competitions and everyone wanted a part in the wealth and adventure exploration offered. When the Spanish discovered America, they took the land and colonized it. Americas was rich in soil, minerals, and goods. This was a way for Spain to become a more powerful nation, so the Spanish seized their opportunity. The English on the other hand, wanted freedom form religious persecution and they wanted a bigger kingdom.The land was excellent for the planting of crops and offered the chance for people to get rich. Both the Spanish and English had different motives and benefits from their settlement of the Americas. They found success in many areas of the land that they settled. They made laws, discovered new places, and claimed a land for their mother nations. The English and Spanish were the biggest land owners of the Americas. Though some of their intentions were selfish, they played a major part in creating what is now the United States. Spanish and English Motives for Settling America AP US History 1 July 2011 In the early fourteenth century, the Americas were home to natives who had lived there for centuries. They had created entire cities for places of worship. These cities were occupied by skilled mathematicians, architects, and astronomers. Thought they did make human sacrifices to their many gods, the natives were able to control their empire and keep it alive at least until the arrival of the European. On the other side of the world, Europeans were looking for opportunities of freedom, land, goods, and most of all riches.There was a high competition for the desired goods of India and China so Europeans began to search for easier routes that would bring them wealth. Spain was the first to discover and claim the Southwest Americas with the historical voyage of Christopher Columbus. Then a couple of years later, had John Cabot claimed the Northeast Americas for England. The Spanish and English differed in motives and benefits from the settlements that they had created in the seventeenth century because of how they treated the natives, colonized, and reasons of leaving Europe. The Spanish were thirsty for riches.Their main reason for leaving Europe was because of God, glory, and gold. Christopher Columbus’s accidental discovery had provided the right opportunity for the Spanish to achieve their goals. The natives welcomed the Spanish into their cities because they thought they were gods. When the Spanish discovered the vast amounts of gold in the area, they decided to conquer the lands and to gain riches and glory. Many natives died from the wars with the Spanish, but what really killed them was disease. Later on as the Spanish colonized southwest America, they brought Christianity to the natives.Missionaries tried to Europeanize the natives. Many Spanish men married native women and had European American children. In New England, the English colonies had different motives. Theirs was religious freedom. At first the natives and the English made peace treaties because of trade and Christianity. But as time passed tensions grew. The English did not intermix with the natives as the Spanish had. The natives were mainly a pestilence that was in the way of land. As with the Spanish, the natives had their populations wiped out because of European diseases and wars.The natives were forced to combine with other tribes and move to the Midwest. The Spanish settled the southwest Americas and the Caribbean. In the New Mexico and Texas areas of present day America, they found little success in their search for gold. They found the Caribbean useful for the crop plantations of tobacco, sugar, and corn. The Spanish spread Christianity to the natives, built forts and missions, and claimed the land for Spain for centuries to come. The Spanish planted their teachings, language, laws, and religion into their colonies and native neighbors.New England had been settled for the land and freedom it offered. Thousands of miles away from England, the Europeans were able to find comfort in freedom of religion. As colonies grew, things started to change. The colonist both fought with each other over land and religion. Government was made up and some of these written laws were placed in today’s constitution. Major cash crops were grown and the colonies grew also. Africans were shipped to New England as slaves to help maintain these large farms. New Englanders started out on a difficult journey but life continued to get better as the colonies grew.The Spanish and English both wanted to find easier routes to the Indies. They wanted the spices and other luxury goods the Asia had to offer. There were high competitions and everyone wanted a part in the wealth and adventure exploration offered. When the Spanish discovered America, they took the land and colonized it. Americas was rich in soil, minerals, and goods. This was a way for Spain to become a more powerful nation, so the Spanish seized their opportunity. The English on the other hand, wanted freedom form religious persecution and they wanted a bigger kingdom.The land was excellent for the planting of crops and offered the chance for people to get rich. Both the Spanish and English had different motives and benefits from their settlement of the Americas. They found success in many areas of the land that they settled. They made laws, discovered new places, and claimed a land for their mother nations. The English and Spanish were the biggest land owners of the Americas. Though some of their intentions were selfish, they played a major part in creating what is now the United States.

What Is the What by Dave Eggers Book Review

What Is the What is an astonishing, eye-opening, and heartbreaking book that defies classification. Once you’ve read it, the story of Valentino Achak Deng refuses to leave your mind. Even if you’re not familiar with the Lost Boys and their struggles to escape from war-torn Sudan, you’ll be drawn into this pseudo-autobiography. What Is the What tells a devastating story but never plays for sympathy. Instead, the hope, complexity, and tragedy of the situation take center stage. Valentino’s story stands alone as powerful and worth reading and Eggers’ superb writing compellingly brings Valentino’s voice and story to life. The novel is a successful portrayal of  a large-scale  tragedy through one man’s story though it does include graphic depictions of suffering and death. Synopsis Valentino Achak Deng was just a boy when Sudan’s civil war found its way to his village. Forced to flee, he walks for months to Ethiopia and later Kenya with hundreds of other boys. Resettled in the US, Valentino struggles to adjust to the mixed blessings of his new life. Book Review What Is the What is drawn from the real-life story of Valentino Achak Deng, one of the Lost Boys of Sudan. The title comes from a local story about the reward of choosing what’s known over what’s unknown. As they flee the destruction around them, though, the Lost Boys are constantly forced to choose the unknown future of refugee camps and life in America. What Is the What describes the interminable walking, the militia and bombs, starvation and disease, and lions and crocodiles that kill countless young boys as they attempt to find refuge in Ethiopia and Kenya. The obstacles of their journey are so astonishing and heartbreaking that you — and they — often wonder how they can go on. Eventually, many of the Lost Boys gain entry to the United States, and they form a vibrant community displaced across the country but constantly in touch by cell phone. Valentino ends up in Atlanta, adjusting to the fact that America offers its own evils and injustices. His past and present are masterfully interwoven through Valentino’s habit of mentally recounting his story to the different people he meets. Reading Valentino’s horrifying story can make the mere act of reading a book feel frivolous. The power of literature, though, is to bring remote stories to life. Eggers is famous for his book,  A Heartbreaking Work of Staggering Genius. That title could easily apply to What Is the What. Book Discussion Group Questions If youve chosen this book for your discussion group, here are some sample questions. Why do you think Valentino/Dominic/Achak had so many names?Why do you think Valentino directs his story towards Michael, Julian, and the clients of the gym?Which one of Valentino’s friends did you like or remember the most?Did you know the plight of the Lost Boys before you read this book? Did it change what you thought about the situation?What details impacted you the most?

The Golden Beach And Shelly Beach - 1822 Words

The places that are being investigated for erosion are Golden Beach, Kings Beach and Shelly Beach. When considering what suitable coastal management strategies could be used in this area to protect the built-up area of private homes, high rise buildings, tourist facilities and the nearby commercial area of Golden Beach shopping center with positive environmental outcomes being mangroves and dunal re-vegetation, positive aesthetic outcomes being looks more natural and relocation of more animal species. The positive economic outcome of the Golden Beach area is that its cheaper and protects from the wind, but the negative is that it takes longer, and the positive social factor is that it gives space to walk dogs and provides more areas to†¦show more content†¦The sources that were found to assist in the building of this report were as follows; the additional resources booklet that was given by Mrs. Mansfield, Chapter 4 – Managing change in coastal environments form the g eography textbook, Dunal explanation sheet, The earth charter, http:// www.ehp.qld.gov.au/coastalmanagement/, www.goldcoast.qld.gov.au (used for comparison of the different management strategies that used between our coasts), www.sunshinecoast.qld.gov.au, www.ehp.qld.gov.au. As I can remember, there was no bias throughout any of these sources, they simply state recommendations, explanations of coastal landforms etc. These sources were very relevant because they extended my understanding of coastal management and helped in developing reasonable strategies to keep our valuable coast landforms. The places that are being investigated for erosion are Golden Beach, Kings Beach and Shelly Beach. When considering what suitable coastal management strategies could be used in this area to protect the built-up area of private homes, high rise buildings, tourist facilities and the nearby commercial area of Golden Beach shopping center with positive environmental outcomes being mangroves and duna l re-vegetation, positive aesthetic outcomes being looks more natural and relocation of more animal species. â€Å"The existing wide shallow sand banks in the passage will further protect Golden Beach and rock walls are not likely to be needed. Sections ofShow MoreRelatedA Report On Beach Tourism2225 Words   |  9 PagesBill. Generally beach means bank of Sea. Broader sense cover the area of beach that â€Å"where the natural waves of water floating the bank of a certain area†. It may be the bank of a big river or Natural Canal or Haor (1). Wikipedia (The free encyclopaedia) stated â€Å"Beaches typically occur in areas along the coast where wave or current action deposits and reworks sediments. It may the coast of an ocean or sea, or the edge of a lake or river†. Beach tourism means travelling in the beach area for recreationRead MoreMarketing Mistakes and Successes175322 Words   |  702 Pagescame up with their own craft brands. For example, Icehouse, a name that conveyed a fake microbrewery image to a beer that was actually produced in megabreweries by Miller Brewing. So too, the pseudoimport Killian’s Irish Red was made by Coors in Golden, Colorado. Killian’s, stocked in retailer’s import cases and commanding a high price, muscled its way abreast of Samuel Adams as the largest specialty beer in the United States. The brewing industry was desperately trying to innovate. But no oneRead MoreStrategic Human Resource Management View.Pdf Uploaded Successfully133347 Words   |  534 PagesManaging Collisions Between People, Cultures, and Organizations. San Francisco: Jossey-Bass Publishers, 1989. Buono and Bowditch. The Human Side of Mergers and Acquisitions, p. 263. Buono and Bowditch. The Human Side of Mergers and Acquisitions. Branch, Shelly. â€Å"The 100 Best Companies to Work For in America,† Fortune (January 11, 1999): 118–44; Thurm, Scott. â€Å"Joining the Fold: Under Cisco’s System, Mergers Usually Work; That Defies the Odds,† Wall Street Journal (March 1, 2000): A1. Page 73 STRATEGICRead More_x000C_Introduction to Statistics and Data Analysis355457 Words   |  1422 PagesTechnology Bob Mattson Eureka College C. Mark Miller York College Megan Mocko University of Florida Kane Nashimoto James Madison University Helen Noble San Diego State University Broderick Oluyede Georgia Southern University Elaine Paris Mercy College Shelly Ray Parsons Aims Community College Judy Pennington-Price Midway College Hazard Community College Jackson County High School ââ€"   Michael I. Ratliff Northern Arizona University David R. Rauth Duquesne University Kevin J. Reeves East Texas Baptist