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| {{More footnotes|date=March 2012}}
| | == distress the poor == |
| '''Accelerator physics''' is a branch of [[applied physics]], concerned with designing, building and operating [[particle accelerator]]s. As such, it can be circumscribed as the study of motion, manipulation and observation of [[Special relativity|relativistic]] [[charged particle beam]]s and their interaction with accelerator structures by [[electromagnetic field]]s.
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| It is also related to other fields:
| | Disabilities, and why this choice<br><br>'I understand, the most important thing is [http://www.dmwai.com/webalizer/kate-spade-14.html ケイトスペード時計人気] the police profession in his heart, or to his skill, can escape, he did not go, he is simply looking for the opportunity to die Ming-chi, he imagined a The real name of the police as hell! 'Luojia Long Road. Maqiu Lin smiled, relieved smile on his face, he smiled and stroked mouse Road with: 'Well [http://www.dmwai.com/webalizer/kate-spade-0.html ケイトスペード中古バッグ] said, in fact, your heart is the most important job, every man has a chivalrous dream, passion, [http://www.dmwai.com/webalizer/kate-spade-13.html kate spade ハンドバッグ] pride, distress the poor, good and evil is a righteous man, a hero dreams often do, put this body uniforms ah, it means you stand [http://www.dmwai.com/webalizer/kate-spade-15.html ケイトスペード クラッチバッグ] up from a dream that Payouyitian nearest place [http://www.dmwai.com/webalizer/kate-spade-10.html ケイトスペード バッグ ショルダー] ...... you do violate the oath , against their conscience, even illegal things, that dream will not therefore change, your heart the most important, is the heaviest of his heart. 'Shao Wan Ge a little impressed when life police, who have some kind of sentiment is not He surprised to see, these usually say nothing Gengzhuobozi with captain naysayers, like Ming Wu general, two piercing staring at the |
| *[[Microwave engineering]] (for acceleration/deflection structures in the [[radio frequency]] range).
| | 相关的主题文章： |
| *[[Optics]] with an emphasis on [[geometrical optics]] (beam focusing and bending) and [[laser physics]] (laser-particle interaction).
| | <ul> |
| *[[Computer technology]] with an emphasis on [[digital signal processing]]; e.g., for automated manipulation of the particle beam.
| | |
| | <li>[http://222.184.12.18:6060/home.php?mod=space&uid=71039 http://222.184.12.18:6060/home.php?mod=space&uid=71039]</li> |
| | |
| | <li>[http://bbs.qdfang.cn/home.php?mod=space&uid=34837 http://bbs.qdfang.cn/home.php?mod=space&uid=34837]</li> |
| | |
| | <li>[http://www.donegalwebsites.ie/cgi-bin/property/viewproperty.cgi http://www.donegalwebsites.ie/cgi-bin/property/viewproperty.cgi]</li> |
| | |
| | </ul> |
|
| |
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| The experiments conducted with particle accelerators are not regarded as part of accelerator physics, but belong (according to the objectives of the experiments) to, e.g., [[particle physics]], [[nuclear physics]], [[condensed matter physics]] or [[materials physics]]. The types of experiments done at a particular accelerator facility are determined by characteristics of the generated [[particle beam]] such as average energy, particle type, intensity, and dimensions.
| | == and soon took the unopened bottle Xinghuacun out == |
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| ==Acceleration and interaction of particles with RF structures== | | May fierce, read one by one over the crime, police capacity is not the whole of it a slap in the face; drink confused, boom sound [http://www.dmwai.com/webalizer/kate-spade-7.html ケイトスペード 財布 通販] foot; cigarette in the other ear, Baji is a slap in the face, though not heavy, in respect of such year standing in front of a bunch of bad dean of students, like you do not need to charge more than taking lessons.<br><br>pick up a few people, imposing stand now, I sin Ting Zhaoxiong growled: 'Starting today, I was Sheepshead Bluff Township police station, absenteeism and get out; not obey commands, get out; notification did not come today , do not want to, get out. all get out, damn police [http://www.dmwai.com/webalizer/kate-spade-2.html ケイトスペード 財布 新作] station just disbanded. '<br><br>this point was Fiat, a look proudly over sin, walk a few steps, when you look back, those eyes blurred with the Police Association, the door to the hospital, the little [http://www.dmwai.com/webalizer/kate-spade-3.html 財布 kate spade] dog that was driving back to the city, with more than sin smiled and said: ' not so easy to want to gloat, he wants to carve apart from me, I'll have to thank him. '<br><br>which the crowd [http://www.dmwai.com/webalizer/kate-spade-7.html ケイトスペード バッグ 新作] to [http://www.dmwai.com/webalizer/kate-spade-1.html ケイトスペード 財布 店舗] mine too, looked at each other, I saw was the new director into the wine market, beep kicking turn the table, and soon took the unopened bottle Xinghuacun out, it snapped his teeth mouth |
| {{See also|Microwave cavity|Shunt impedance|Superconducting Radio Frequency|Reciprocity (electromagnetism)}}
| | 相关的主题文章： |
| | <ul> |
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| | <li>[http://cup.nenu.edu.cn/discuz/forum.php?mod=viewthread&tid=42877 http://cup.nenu.edu.cn/discuz/forum.php?mod=viewthread&tid=42877]</li> |
| | |
| | <li>[http://www.cqhuifeng.com/plus/feedback.php?aid=14 http://www.cqhuifeng.com/plus/feedback.php?aid=14]</li> |
| | |
| | <li>[http://www.ccins.org?q=node/2 http://www.ccins.org?q=node/2]</li> |
| | |
| | </ul> |
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| [[File:Desy tesla cavity01.jpg|thumb|Superconducting [[niobium]] [[microwave cavity|cavity]] for acceleration of ultrarelativistic particles from the TESLA project]]
| | == not the hotel lobby. == |
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| While it is possible to accelerate charged particles using electrostatic fields, like in a [[Cockcroft-Walton voltage multiplier]], this method has limits given by [[electrical breakdown]] at high voltages. Furthermore, due to electrostatic fields being conservative, the maximum voltage limits the kinetic energy that is applicable to the particles.
| | 'But ...... it is right? She is the police.' Head hesitate Road.<br><br>'how inappropriate, police also need emotional life [http://www.dmwai.com/webalizer/kate-spade-2.html 時計 ケイトスペード] ah? okay, you want to become my brother's table, and I [http://www.dmwai.com/webalizer/kate-spade-6.html ケイトスペード リボン バッグ] wish for it, it is not even a [http://www.dmwai.com/webalizer/kate-spade-6.html ケイトスペード リボン バッグ] thing that can come about her, let her contact and contact with the outside, that is merit an ah. 'Luojia Long Road.<br><br>'This ......' Head anxious to go now, and it is estimated that the [http://www.dmwai.com/webalizer/kate-spade-10.html ケイトスペード バッグ ショルダー] identity of the police to make him a little hesitant.<br><br>'you offer it, the money we give you money, this busy got to help.' Wang Tao Shen repair bitter face.<br><br>'No, no, [http://www.dmwai.com/webalizer/kate-spade-12.html kate spade 長財布] help to any money, we do not have friends? huh ...... OK, though.'<br><br>'You worry, I'll take you to morrow, where she works to introduce to you.'<br><br>'hand in hand Kazakhstan, we morrow morning to pick you up.'<br><br>this match up just right, Lee interchangeable heads cool phone, address, agreed a good time and meeting place, just leave down the stairs, not the hotel lobby. |
| | | 相关的主题文章： |
| To circumvent this problem, [[linear particle accelerator]]s operate using time-varying fields. To control this fields using hollow macroscopic structures through which the particles are passing (wavelength restrictions), the frequency of such acceleration fields is located in the [[radio frequency]] region of the electromagnetic spectrum.
| | <ul> |
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| The space around a particle beam is evacuated to prevent scattering with gas atoms, requiring it to be enclosed in a vacuum chamber (or ''beam pipe''). Due to the strong [[electromagnetic field]]s that follow the beam, it is possible for it to interact with any electrical impedance in the walls of the beam pipe. This may be in the form of a resistive impedance (i.e., the finite resistivity of the beam pipe material) or an inductive/capacitive impedance (due to the geometric changes in the beam pipe's cross section).
| | <li>[http://autochecksouthflorida.com/cgi-bin/guestbook.cgi http://autochecksouthflorida.com/cgi-bin/guestbook.cgi]</li> |
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| These impedances will induce ''wakefields'' (a strong warping of the electromagnetic field of the beam) that can interact with later particles. Since this interaction may have negative effects, it is studied to determine its magnitude, and to determine any actions that may be taken to mitigate it.
| | <li>[http://www.zzctv.com/plus/feedback.php?aid=507 http://www.zzctv.com/plus/feedback.php?aid=507]</li> |
| | | |
| ==Beam dynamics==
| | <li>[http://ccxdk.com/home.php?mod=space&uid=45687 http://ccxdk.com/home.php?mod=space&uid=45687]</li> |
| {{See also|Particle beam|Strong focusing|Beam emittance|Radiation damping}}
| | |
| | | </ul> |
| Due to the high velocity of the particles, and the resulting [[Lorentz force]] for magnetic fields, adjustments to the beam direction are mainly controlled by [[magnetostatics|magnetostatic]] fields that deflect particles. In most accelerator concepts (excluding compact structures like the [[cyclotron]] or [[betatron]]), these are applied by dedicated [[electromagnets]] with different properties and functions. An important step in the development of these types of accelerators was the understanding of [[strong focusing]].<ref>{{cite doi|10.1006/aphy.2000.6012}}</ref> [[Dipole magnet]]s are used to guide the beam through the structure, while [[quadrupole magnet]]s are used for beam focusing, and [[sextupole magnet]]s are used for correction of [[Dispersion (optics)|dispersion]] effects.
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| A particle on the exact design trajectory (or design ''orbit'') of the accelerator only experiences dipole field components, while particles with transverse position deviation <math>\scriptstyle x(s)</math> are re-focused to the design orbit. For preliminary calculations, neglecting all fields components higher than quadrupolar, an inhomogenic [[Hill differential equation]]
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| :<math> \frac{d^2}{ds^2}\,x(s) + k(s)\,x(s) = \frac{1}{R} \, \frac{\Delta p}{p} </math>
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| can be used as an approximation,<ref>{{cite book
| |
| | last = Wille
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| | first = Klaus
| |
| | title = Particle Accelerator Physics: An Introduction
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| | publisher = [[Oxford University Press]]
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| | year = 2001
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| | isbn = 978-0-19-850549-5
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| }} (slightly different notation)</ref> with
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| :a non-constant focusing force <math>\scriptstyle k(s)</math>, including strong focusing and [[weak focusing]] effects
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| :the relative deviation from the design beam impulse <math>\scriptstyle \Delta p / p</math> | |
| :the trajectory curvature radius <math>\scriptstyle R</math>, and
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| :the design path length <math>\scriptstyle s</math>,
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| thus identifying the system as a [[parametric oscillator]]. Beam parameters for the accelerator can then be calculated using [[Ray transfer matrix analysis]]; e.g., a quadrupolar field is analogous to a lens in geometrical optics, having similar properties regarding beam focusing (but obeying [[Earnshaw's theorem]]).
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| The general equations of motion originate from [[Theory of relativity|relativistic]] [[Hamiltonian mechanics]], in almost all cases using the [[Paraxial approximation]]. Even in the cases of strongly nonlinear magnetic fields, and without the paraxial approximation, a [[Lie group|Lie transform]] may be used to construct an integrator with a high degree of accuracy.{{Citation needed|date=December 2011}}
| |
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| ==Modeling Codes==
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| {{See also|Accelerator Physics Codes|Geant4|Methodical_Accelerator_Design}}
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| There are many different software packages available for modeling the different aspects of accelerator physics.
| |
| One must model the elements that create the electric and magnetic fields, and then one must model the charged particle evolution within those fields. A popular code for beam dynamics, designed by [[CERN]] is MAD, or [[Methodical Accelerator Design]].
| |
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| ==Beam diagnostics==
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| A vital component of any accelerator are the diagnostic devices that allow various properties of the particle bunches to be measured.
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| A typical machine may use many different types of measurement device in order to measure different properties. These include (but are not limited to) Beam Position Monitors (BPMs) to measure the position of the bunch, screens (fluorescent screens, Optical Transition Radiation (OTR) devices) to image the profile of the bunch, wire-scanners to measure its cross-section, and toroids or ICTs to measure the bunch charge (i.e., the number of particles per bunch).
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| While many of these devices rely on well understood technology, designing a device capable of measuring a beam for a particular machine is a complex task requiring much expertise. Not only is a full understanding of the physics of the operation of the device necessary, but it is also necessary to ensure that the device is capable of measuring the expected parameters of the machine under consideration.
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| Success of the full range of beam diagnostics often underpins the success of the machine as a whole.
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| ==Machine tolerances==
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| Errors in the alignment of components, field strength, etc., are inevitable in machines of this scale, so it is important to consider the tolerances under which a machine may operate.
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| Engineers will provide the physicists with expected tolerances for the alignment and manufacture of each component to allow full physics simulations of the expected behaviour of the machine under these conditions. In many cases it will be found that the performance is degraded to an unacceptable level, requiring either re-engineering of the components, or the invention of algorithms that allow the machine performance to be 'tuned' back to the design level.
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| This may require many simulations of different error conditions in order to determine the relative success of each tuning algorithm, and to allow recommendations for the collection of algorithms to be deployed on the real machine.
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| ==See also==
| |
| {{portal|Physics}}
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| * [[Particle accelerator]]
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| * [[list of publications in physics#Accelerator physics|Significant publications for accelerator physics]]
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| ==References==
| |
| {{Reflist}}
| |
| * {{cite book | url=http://books.google.com/books?id=v9SoaCWFgigC&printsec=frontcover&dq=Accelerator+physics&hl=en&sa=X&ei=N91ZT8u3OcjmiALZyo3TCw&ved=0CFwQ6AEwBw#v=onepage&q=Accelerator%20physics&f=false | title=Advances of accelerator physics and technologies | publisher=World Scientific | year=1993 | accessdate=March 9, 2012 | last1 = Schopper | first1 = Herwig F. | isbn = 981-02-0957-6 }}
| |
| * {{cite book | url=http://www.worldcat.org/title/particle-accelerator-physics-2-nonlinear-and-higher-order-beam-dynamics/oclc/174173289&referer=brief_results | title=Particle accelerator physics 2. Nonlinear and higher-order beam dynamics | publisher=Springer | year=1995 | accessdate=March 9, 2012 | last1 = Wiedemann | first1 = Helmut | isbn = 0-387-57564-2 }}
| |
| * {{cite book | url=http://books.google.com/books?id=VTc8Sdld5S8C&printsec=frontcover&dq=Accelerator+physics&hl=en&sa=X&ei=N91ZT8u3OcjmiALZyo3TCw&ved=0CDIQ6AEwAA#v=onepage&q=Accelerator%20physics&f=false | title=Accelerator physics | publisher=[[World Scientific]] | year=2004 | edition = 2nd | last1 = Lee | first1 = Shyh-Yuan | isbn = 978-981-256-200-5 }}
| |
| * {{cite book
| |
| | editor1-last = Chao | editor1-first = Alex W.
| |
| | editor2-last = Tigner | editor2-first = Maury
| |
| | edition = 2nd
| |
| | title=Handbook of accelerator physics and engineering
| |
| | publisher=[[World Scientific]]
| |
| | year=2013
| |
| | isbn = 978-981-4417-17-4
| |
| | url = http://www.worldscientific.com/worldscibooks/10.1142/8543}}
| |
| * {{cite book | url=http://www.worldscientific.com/worldscibooks/10.1142/9079 | title=Reviews of Accelerator Science and Technology Volume 6 | publisher=World Scientific | year=2014 | last1 = Chao | first1 = Alex W. | last2 = Chou | first2 = Weiren | isbn = 978-981-4583-24-4}}
| |
| * {{cite book | url=http://www.worldscientific.com/worldscibooks/10.1142/8721 | title=Reviews of Accelerator Science and Technology Volume 5 | publisher=World Scientific | year=2013 | last1 = Chao | first1 = Alex W. | last2 = Chou | first2 = Weiren | isbn = 978-981-4449-94-6}}
| |
| * {{cite book | url=http://www.worldscientific.com/worldscibooks/10.1142/8380 | title=Reviews of Accelerator Science and Technology Volume 4 | publisher=World Scientific | year=2012 | last1 = Chao | first1 = Alex W. | last2 = Chou | first2 = Weiren | isbn = 978-981-438-398-1}}
| |
| | |
| ==External links== | |
| * [http://cbp.lbl.gov/ UCB/LBL Beam Physics site]
| |
| * [http://www.bnl.gov/bnlweb/history/focusing.asp BNL page on The Alternating Gradient Concept]
| |
| | |
| {{Physics-footer}}
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| [[Category:Accelerator physics]]
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| [[Category:Experimental particle physics]]
| |
distress the poor
Disabilities, and why this choice
'I understand, the most important thing is ケイトスペード時計人気 the police profession in his heart, or to his skill, can escape, he did not go, he is simply looking for the opportunity to die Ming-chi, he imagined a The real name of the police as hell! 'Luojia Long Road. Maqiu Lin smiled, relieved smile on his face, he smiled and stroked mouse Road with: 'Well ケイトスペード中古バッグ said, in fact, your heart is the most important job, every man has a chivalrous dream, passion, kate spade ハンドバッグ pride, distress the poor, good and evil is a righteous man, a hero dreams often do, put this body uniforms ah, it means you stand ケイトスペード クラッチバッグ up from a dream that Payouyitian nearest place ケイトスペード バッグ ショルダー ...... you do violate the oath , against their conscience, even illegal things, that dream will not therefore change, your heart the most important, is the heaviest of his heart. 'Shao Wan Ge a little impressed when life police, who have some kind of sentiment is not He surprised to see, these usually say nothing Gengzhuobozi with captain naysayers, like Ming Wu general, two piercing staring at the
相关的主题文章：
and soon took the unopened bottle Xinghuacun out
May fierce, read one by one over the crime, police capacity is not the whole of it a slap in the face; drink confused, boom sound ケイトスペード 財布 通販 foot; cigarette in the other ear, Baji is a slap in the face, though not heavy, in respect of such year standing in front of a bunch of bad dean of students, like you do not need to charge more than taking lessons.
pick up a few people, imposing stand now, I sin Ting Zhaoxiong growled: 'Starting today, I was Sheepshead Bluff Township police station, absenteeism and get out; not obey commands, get out; notification did not come today , do not want to, get out. all get out, damn police ケイトスペード 財布 新作 station just disbanded. '
this point was Fiat, a look proudly over sin, walk a few steps, when you look back, those eyes blurred with the Police Association, the door to the hospital, the little 財布 kate spade dog that was driving back to the city, with more than sin smiled and said: ' not so easy to want to gloat, he wants to carve apart from me, I'll have to thank him. '
which the crowd ケイトスペード バッグ 新作 to ケイトスペード 財布 店舗 mine too, looked at each other, I saw was the new director into the wine market, beep kicking turn the table, and soon took the unopened bottle Xinghuacun out, it snapped his teeth mouth
相关的主题文章：
not the hotel lobby.
'But ...... it is right? She is the police.' Head hesitate Road.
'how inappropriate, police also need emotional life 時計 ケイトスペード ah? okay, you want to become my brother's table, and I ケイトスペード リボン バッグ wish for it, it is not even a ケイトスペード リボン バッグ thing that can come about her, let her contact and contact with the outside, that is merit an ah. 'Luojia Long Road.
'This ......' Head anxious to go now, and it is estimated that the ケイトスペード バッグ ショルダー identity of the police to make him a little hesitant.
'you offer it, the money we give you money, this busy got to help.' Wang Tao Shen repair bitter face.
'No, no, kate spade 長財布 help to any money, we do not have friends? huh ...... OK, though.'
'You worry, I'll take you to morrow, where she works to introduce to you.'
'hand in hand Kazakhstan, we morrow morning to pick you up.'
this match up just right, Lee interchangeable heads cool phone, address, agreed a good time and meeting place, just leave down the stairs, not the hotel lobby.
相关的主题文章：