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You searched for subject:(vacuum breakdowns). Showing records 1 – 2 of 2 total matches.

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1. Olofsson, Joel. Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL.

Degree: Physics and Astronomy, 2018, Uppsala University

In the planned linear accelerator called Compact Linear Collider, CLIC, electrons and positrons will be accelerated to velocities near the speed of light. A limiting factor in accelerating structures are vacuum breakdowns, which are electrical discharges from a surface as a result of a large electric field being applied. In the preparatory studies for the CLIC, Uppsala University in collaboration with The European Organization for Nuclear Research, CERN, is building a DC Spark system to analyze vacuum breakdowns. This system containing large planar electrodes will be cooled down all the way down to around 4 K in order to limit the rate of wich vacuum breakdowns happen. When cooling a system like this, which consists of different components made of different materials there is the question of how the system will be affected. The objective of this project is to investigate how the cooling will affect the stability in terms of stresses and to analyze the cool down time of the system. Another goal is to make a material recommendation for a few parts based on the results. This will be done by simulating the cooling in COMSOL Multiphysics, which is a program that uses finite element analysis to solve complex problems where different branches of physics interact. The conclusion is that the system will most likely be stable as it is and there is no need to redesign it. The choice of recommended material is alumina with the reason being it should cause the least stress and the smallest gap between the electrodes when the cooling is done. There was no big difference in the cool down time between the materials. Further studies and simulations on the system is also recommended since there are many factors not taken into consideration in this study.

Subjects/Keywords: accelerator; compact linear collider; clic; cern; vacuum breakdowns; breakdowns; comsol; cryo-cooled; cryogenics; cryocooler; DC spark; electrode system; Accelerator Physics and Instrumentation; Acceleratorfysik och instrumentering

…x5B;3] Shipman Nicolas, Manchester U. and CERN, Experimental study of DC vacuum… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Olofsson, J. (2018). Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL. (Thesis). Uppsala University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353895

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Olofsson, Joel. “Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL.” 2018. Thesis, Uppsala University. Accessed September 30, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353895.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Olofsson, Joel. “Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL.” 2018. Web. 30 Sep 2020.

Vancouver:

Olofsson J. Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL. [Internet] [Thesis]. Uppsala University; 2018. [cited 2020 Sep 30]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353895.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Olofsson J. Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL. [Thesis]. Uppsala University; 2018. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353895

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Aghazarian, Maro. Study of the effects of roughness, ultraviolet radiation, multipactoring and magnetic field on vacuum breakdown.

Degree: MS, 0139, 2013, University of Illinois – Urbana-Champaign

Breakdowns in vaccuum and the factors a ffecting them have been studied for more than a hundred years, with applications ranging from high voltage isolation to space propulsion. In current thermonuclear fusion projects, one of the methods of heating the plasma is through ion cyclotron radiofrequency heating. ICRF antennas are used to this end, while the voltage and hence the power possible to deliver through these antennas is limited because of breakdowns. The focus of this research has been to study some of the factors suspected to a ffect these breakdowns, namely, the macroscopic surface roughness and ultraviolet radiation, with the ultimate purpose of raising the breakdown threshold of ICRF antennas in order to deliver more power to thermonuclear fusion plasmas. Macroscopic surface roughness did not signify any regular prediction of breakdown threshold in copper and aluminum electrodes subjected to DC voltage. Though the presence of ultraviolet radiation lowered the breakdown threshold on average, the difference in the mean values was smaller than the uncertainty in measurement, making the results inconclusive until further studies are performed. Advisors/Committee Members: Ruzic, David N. (advisor).

Subjects/Keywords: vacuum breakdowns; Ion Cyclotron Range of Frequencies (ICRF) antennas; breakdown; macroroughness; high voltage breakdown; electrical breakdown; surface roughness; effects of UV on breakdown; vacuum breakdown; ICRF antenna breakdown

vacuum. However, this is not enough as low-voltage, high-gradient breakdowns are not the only… …rod mechanisms, (10) main port bellows, (11) RF vacuum windows, (12… …of Energy. DT Deuterium-Tritium. Eb Electric field at which breakdowns happen. EDS… …at Urbana-Champaign. UHV Ultra High Vacuum. UV Ultraviolet. xii CHAPTER 1… …in ITER can be seen in figure 1.4. Most often a vacuum region is assumed between the wall… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Aghazarian, M. (2013). Study of the effects of roughness, ultraviolet radiation, multipactoring and magnetic field on vacuum breakdown. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/45506

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Aghazarian, Maro. “Study of the effects of roughness, ultraviolet radiation, multipactoring and magnetic field on vacuum breakdown.” 2013. Thesis, University of Illinois – Urbana-Champaign. Accessed September 30, 2020. http://hdl.handle.net/2142/45506.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Aghazarian, Maro. “Study of the effects of roughness, ultraviolet radiation, multipactoring and magnetic field on vacuum breakdown.” 2013. Web. 30 Sep 2020.

Vancouver:

Aghazarian M. Study of the effects of roughness, ultraviolet radiation, multipactoring and magnetic field on vacuum breakdown. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2013. [cited 2020 Sep 30]. Available from: http://hdl.handle.net/2142/45506.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Aghazarian M. Study of the effects of roughness, ultraviolet radiation, multipactoring and magnetic field on vacuum breakdown. [Thesis]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/45506

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.