A Proof Of Principle Demonstration Of 805 M Hz High Gradient Srf Cavities

2195 words - 9 pages

A Proof-of-Principle Demonstration of 805 MHz High Gradient SRF Cavities

An accelerating gradient of 50 MV/m at an unloaded quality factor (Q0) of 1.4 x 1010 was achieved with a single-cell 805 MHz superconducting radio-frequency (SRF) cavity. This accelerating gradient is more than twice as high as the previous maximum gradient at 805 MHz, and the result demonstrates that 805 MHz cavities, which have a larger beam aperture of 10 cm than 6-7 cm for 1.3 GHz high-gradient cavities, can be used, in principle, as high-gradient cavities for various purposes, especially suited for protons, light ions and other machines that require lower beam impedances due to a larger beam aperture of 10 cm compared to 6-7 cm with 1.3 GHz high-gradient cavities. One remarkable fact is that this cavity was only treated with a usual buffered chemical polishing of ~150 microns and an ultra-high vacuum baking at 115-130 ˚C for 48 hours, and it did not have without high temperature treatment except for a vacuum baking at 115-130 ˚C for 48 hours, and without or any costly electro-polishing, that which has been required for 1.3 GHz cavities to get to very high gradients.
SRF cavities have been used successfully for particle accelerators since 1970s [1]. A large fraction of them are is made of bulk niobium (Nb) due to the fact that it niobium has the highest superconducting transition temperature of ~9.2 K as a single metalamong pure metals. The benefits of SRF cavities compared to normal conducting structures are 1) lower losses due to the intrinsic nature of superconductivity, 2) they can run at higher gradients forin long pulses orand CW operations, and 3) lower beam impedances due to larger beam apertures. However, Nb SRF cavities are fundamentally limited by the RF critical field of Nb, which is thought to be approximately 200 mT. If the ratio of the peak magnetic field to the accelerating gradient Bpk/Eacc, is 4, then the maximum achievable accelerating gradient (Eacc) in Nb SRF cavities is 50 MV/m. The fundamental limitation of Nb SRF cavities, however, is its relatively low achievable accelerating gradient (Eacc) due to the RF critical magnetic field of Nb, which is proportional to Eacc and has been thought to be approximately 200 mT that corresponds to an Eacc of ~50 MV/m if the ratio of peak magnetic field to accelerating gradient, Bpk/Eacc, is 4.
Historically, the design Eacc was 5-10 MV/m until mid 1990s, but withwhen a global effort called TESLA Technology Collaboration (TTC), which started early 1990s aiming at TeV Energy Superconducting Linear Accelerator (TESLA), lead to a significant increase in the achievable Eacc has increased significantly and now the design Eacc is often above has increased to >20 MV/m, e.g., 23.5 MV/m for European X-ray Free Electron Laser (XFEL) and 35 MV/m for the International Linear Collider (ILC). These TTC high-gradient studies have been focused at 1.3 GHz due to the fact that the ILC decided to use...

Find Another Essay On A Proof-of-Principle Demonstration of 805 MHz High Gradient SRF Cavities

Burden Of Proof Essay

4597 words - 18 pages INTRODUCTIONEvery story has its own contents, which is the combination of various facts. Every person has to establish facts that go in his favor or against his opponent. The burden of proof (onus) means the obligation to prove a fact. As per onus probandi, the burden of proof lies upon the party who would fail upon the party who would fail if no evidence were given at all. The general principle is that the party who wish to establish the truth

Proof of Courage Essay

1513 words - 6 pages course, without a doubt, depicted courageous individuals. Yet many of them would only fall under one or two labels of courage. The solution to the conundrum is simple. Courage needs to be defined by way of mathematical proof (regarding the approach, not the content) rather than from the subject's actions. Through an indirect approach it becomes easy to differentiate courage from similar falsities. Courage is a person's ability to knowingly surpass

Proof of God's Existence

1193 words - 5 pages Josh TatumFoundations of FaithRoy SharpNovember 21, 2014Existence of GodThroughout history, one can see that for any significant movement, there is usually a significant counter-movement. It seems like more often than not, these counter movements are lead by young adults ranging in age from 17-25. For whatever developmental reasons, we are easily influenced by our peers, the popular opinion, or the media and related propaganda, typically

Demonstration of the Male Dominance and Superiority

1255 words - 5 pages romanticizes about setting up a hotel by a lake overseas somewhere in Romania, it is an exaggerated fantasy in which Miss Julie will serve not only as his financial support but also his personal servant, inverting their roles and reinforcing the idea of patriarchy and male dominance. Though Miss Julie was born into the upper stratum of society granting her authoritative power, Jean faces a superiority complex and declares that he “wasn’t born to

Principle of management

1033 words - 4 pages requires and not much more - decisions are left to people.This reliance on people for all decision-making is a serious limiting factor for the long term growth of Enterprise Applications.•It severely limits the ability to attain straight through processing in any but the most simple processes•It means that 24x7 operation requires 24x7 staffing•It means that improving operational, high-volume transactions with analytic insight is almost

Language as Proof of Power

985 words - 4 pages that Standard English is the only way to make sense of this world and the only ways in gaining social attention. In his 1979 essay, “If Black English Isn't a Language, Then Tell Me, What Is?” James Baldwin stated, “language is also a political instrument, means, and a proof of power,”(MacNeil, Cran 134), and I believe that even thirty years later, Standard English stands as the only dialect with dominating social power. We are still not living in

Scarlet letter proof of atroph

697 words - 3 pages ATROPINE POISONING: WAS IT THE CAUSE OF DIMMESDALE'S DEATH? In an article in the New England Journal of Medicine, Dr. Jemshed A. Khan claims that Roger Chillingworth poisoned Arthur Dimmesdale with the drug atropine in Hawthorne's The Scarlet Letter. Certainly, Chillingworth was "a man of skill in all Christian modes of physical science" (Hawthorne 65) and was very knowledgeable about medicinal roots and herbs (Hawthorne 65). Undoubtedly, he

William Golding’s Lord of the Flies: A Laboratory Demonstration of Human Behaviour Sans the Restraints of Civilization”

1244 words - 5 pages Jack, a naval officer arrives on a rescue ship and escorts the boys back to civilization. However, the Edenic island is on fire and in this realistic novel, Golding shows symbolically the fall of man; democracy is made to bow down before dictatorship; evil wins at the expense of good; and civilization loses at the hands of barbarism. Lord of the Flies is indeed a demonstration under laboratory conditions of the forms assumed by human behaviour

My essay gives a description of the cost principle, revenue recognition principle, matching principle and all of there differences, all the work is cited and refrenced

1235 words - 5 pages , you go back to your books and see that your automobile is still recorded at $35 000, even though it is only worth $18 000. In order to compensate you have an "Accumulated Amortization - car" account with a credit balance of $17 000. This shows that you can still have the asset recorded at cost, while only being worth market value. The Matching Principle: The Matching Principle states that expenses should be matched with revenues in the fiscal

Proof of the Existence of Evolution

602 words - 2 pages proof of Dinosaurs once roaming the earth. Fossils are usually found in sedimentary rock. Sedimentary rock is formed by layers of silt or mud on top of each other; thus, the resulting rock contains a series of horizontal layers, or strata. As these Sedimentary rocks form, they bury organism, bones, pollen, shells. Bones, which over time will fully encase, and form a fossil. Each layer of sedimentary rock contains fossils which are typical for a

Descartes Third Meditation: Proof of Gods Existence

1350 words - 5 pages Descartes' Third Meditation: Proof of God's Existence In Rene Descartes Meditations on First Philosophy, Descartes is seeking to find a system of stable, lasting and certain knowledge, which he can ultimately regard as the Truth. In his methodical quest to carry out his task, Descartes eventually arrives at the proverbial fork in the road: how to bridge the knowledge of self with that of the rest of the world. Descartes’ answer to this is to

Similar Essays

Latitudinal Gradient Of Species Diversity Essay

2015 words - 8 pages Latitudinal Gradient of Species Diversity The latitudinal gradient in species diversity is one of the most striking patterns in the distribution of organisms on the planet. Simply put, the average number of species per unit area increases dramatically the closer the area is to the equator, almost entirely regardless of the type of organism being considered (Pianka, 1994). Researchers investigating the gradient have formulated a wide variety

A Rational Demonstration Of Irrational Thought

603 words - 2 pages Voltaire's work Candide is an absurd, irrational story that takes the reader to almost every part of the world in a critical analysis of enlightenment thought. Readers may view Candide as a work that encompasses enlightenment thought. On the contrary however, Candide is indeed a correction and criticism of popular enlightenment ideals. Mainly, Voltaire focuses on the irrationality of the "best of all worlds" philosophy and in the end

Demonstration Of Freedom Essay

847 words - 4 pages Throughout time in America, freedom has always been a main point of interest to everyone who calls it home. William Faulkner once stated, “We must be free not because we claim freedom, but because we practice it.” To many this quote may mean nothing, but to the writer it is more than just words. Freedom is treating every single person equal and with dignity. Freedom is sharing the same rights and privileges with fellow citizens no matter

Studies Of Quench Locations In Ilc Cavities

1208 words - 5 pages -ionized water removes potential field emitters from the cavity surface. And, cleanroom assembly and slow pump-down is a critical step that prevents possible contamination of the surface. If the preparation process is less-than-optimal at some point, the RF gradient of a superconducting cavity will be limited to a lower gradient and quality factor. Thus a lot of research is devoted to understanding and optimizing current treatments of SRF cavities