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High gradient RF breakdown studies.

Laurent, Lisa Leanne.

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High gradient RF breakdown studies.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	High gradient RF breakdown studies./
Author:	Laurent, Lisa Leanne.
Description:	204 p.
Notes:	Adviser: Neville C. Luhmann, Jr.
Contained By:	Dissertation Abstracts International63-08B.
Subject:	Engineering, Electronics and Electrical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3062236
ISBN:	0493781455

High gradient RF breakdown studies.
Laurent, Lisa Leanne.

High gradient RF breakdown studies. - 204 p.

Adviser: Neville C. Luhmann, Jr.

Thesis (Ph.D.)--University of California, Davis, 2002.

Higher accelerating gradients are required by future demands for TeV electron linear colliders. With higher energy comes the challenge of handling stronger electromagnetic fields in the accelerator structures and in the microwave sources that supply the power. A limit on the maximum field gradient is imposed by rf electrical breakdown. Investigating methods to achieve higher gradients and to better understand the mechanisms involved in the rf breakdown process has been the focal point of this study.

ISBN: 0493781455Subjects--Topical Terms:

626636
Engineering, Electronics and Electrical.

High gradient RF breakdown studies.
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005 20110510
008 110510s2002 eng d
020 $a 0493781455
035 $a (UnM)AAI3062236
035 $a AAI3062236
040 $a UnM $c UnM
100 1 $a Laurent, Lisa Leanne. $3 1259851
245 1 0 $a High gradient RF breakdown studies.
300 $a 204 p.
500 $a Adviser: Neville C. Luhmann, Jr.
500 $a Source: Dissertation Abstracts International, Volume: 63-08, Section: B, page: 3765.
502 $a Thesis (Ph.D.)--University of California, Davis, 2002.
520 $a Higher accelerating gradients are required by future demands for TeV electron linear colliders. With higher energy comes the challenge of handling stronger electromagnetic fields in the accelerator structures and in the microwave sources that supply the power. A limit on the maximum field gradient is imposed by rf electrical breakdown. Investigating methods to achieve higher gradients and to better understand the mechanisms involved in the rf breakdown process has been the focal point of this study.
520 $a A systematic series of rf breakdown experiments have been conducted at Stanford Linear Accelerator Center utilizing a transmission cavity operating in the TM<sub>020</sub> mode. A procedure was developed to examine the high gradient section of the cavity in an electron microscope. The results have revealed that breakdown asymmetry exists between opposing high gradient surfaces. During breakdown, a plasma formation is detected localized near the surface with no visible evidence of an arc traversing the gap. These findings support the theory that high frequency rf breakdown is a single surface phenomenon.
520 $a Other results from this study have shown that breakdown can occur at relatively low voltages when surface irregularities exist and along grain boundaries. A series of steps have been developed through this study that have significantly reduced the number of breakdowns that occur along grain boundaries.
520 $a Testing under various vacuum conditions (10<super>−11</super>–10<super> −5</super> Torr) have revealed that while the breakdown threshold remained the same, the field emitted current density increased by almost two orders of magnitude. This suggests that the total field emitted current density is not the critical parameter in the initiation of high frequency vacuum breakdown.
520 $a In the course of this study, microparticles were carefully tracked before and after rf processing. The outcome of this research suggests that expensive cleanroom facilities may not offer any advantage over practicing good cleaning and handling techniques.
520 $a To understand the relationship between coupling and breakdown, two cavities having different external <italic>Q</italic>-values were rf tested to the same field gradients. Significantly more damage occurred in the low <italic>Q</italic> structure. Factors such as location, number, and distribution of breakdown sites are presented.
590 $a School code: 0029.
650 4 $a Engineering, Electronics and Electrical. $3 626636
650 4 $a Physics, Electricity and Magnetism. $3 1019535
690 $a 0544
690 $a 0607
710 2 0 $a University of California, Davis. $3 1018682
773 0 $t Dissertation Abstracts International $g 63-08B.
790 $a 0029
790 1 0 $a Luhmann, Neville C., Jr., $e advisor
791 $a Ph.D.
792 $a 2002
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3062236