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

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1. Vlahacos, Constantine Peter. A SCANNING SQUID MICROSCOPE FOR IMAGING HIGH-FREQUENCY MAGNETIC FIELDS.

Degree: Electrical Engineering, 2009, University of Maryland

This thesis examines the design and operation of a large-bandwidth scanning SQUID microscope for spatially imaging high frequency magnetic fields. Towards this end, I present results on a cryo-cooled 4.2 K scanning SQUID microscope with a bandwidth of dc to 2 GHz and a sensitivity of about 52.4 nT per sample. By using a thin-film hysteretic Nb dc-SQUID and a pulsed sampling technique, rather than a non-hysteretic SQUID and a flux-locked loop, the bandwidth limitation of existing scanning SQUID microscopes is overcome. The microscope allows for non-contact images of time-varying magnetic field to be taken of room-temperature samples with time steps down to 50 ps and spatial resolution ultimately limited by the size of the SQUID to about 10 micrometers. The new readout scheme involves repeatedly pulsing the bias current to the dc SQUID while the voltage across the SQUID is monitored. Using a fixed pulse amplitude and applying a fixed dc magnetic flux allows the SQUID to measure the applied magnetic flux with a sampling time set by the pulse length of about 400 ps. To demonstrate the capabilities of the microscope, I imaged magnetic fields from 0 Hz (static fields) up to 4 GHz. Samples included a magnetic loop, microstrip transmission lines, and microstrip lines with a break in order to identify and isolate electrical opens in circuits. Finally, I discuss the operation and modeling of the SQUID and how to further increase the bandwidth of the microscope to allow bandwidth of upwards of 10 GHz. Advisors/Committee Members: Wellstood, Frederick C. (advisor).

Subjects/Keywords: Engineering, Electronics and Electrical; Physics, Condensed Matter; cryo-cooled; high-frequency magnetic fields; imaging; Microscopy; Scanning SQUID microscope; SQUID

…for sampling a periodic, time-varying magnetic field using a cryo-cooled hysteretic dc-SQUID… 

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

APA (6th Edition):

Vlahacos, C. P. (2009). A SCANNING SQUID MICROSCOPE FOR IMAGING HIGH-FREQUENCY MAGNETIC FIELDS. (Thesis). University of Maryland. Retrieved from http://hdl.handle.net/1903/10223

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):

Vlahacos, Constantine Peter. “A SCANNING SQUID MICROSCOPE FOR IMAGING HIGH-FREQUENCY MAGNETIC FIELDS.” 2009. Thesis, University of Maryland. Accessed September 28, 2020. http://hdl.handle.net/1903/10223.

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

MLA Handbook (7th Edition):

Vlahacos, Constantine Peter. “A SCANNING SQUID MICROSCOPE FOR IMAGING HIGH-FREQUENCY MAGNETIC FIELDS.” 2009. Web. 28 Sep 2020.

Vancouver:

Vlahacos CP. A SCANNING SQUID MICROSCOPE FOR IMAGING HIGH-FREQUENCY MAGNETIC FIELDS. [Internet] [Thesis]. University of Maryland; 2009. [cited 2020 Sep 28]. Available from: http://hdl.handle.net/1903/10223.

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

Council of Science Editors:

Vlahacos CP. A SCANNING SQUID MICROSCOPE FOR IMAGING HIGH-FREQUENCY MAGNETIC FIELDS. [Thesis]. University of Maryland; 2009. Available from: http://hdl.handle.net/1903/10223

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

2. 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

…materials connected to each other are very likely to cause stress on each other when being cooled… …whole object aims to be cooled down to. 12 • Heat Flux defines the thermal flux of a… …to be cooled down to desired temperature can be measured. An uncertainty of 0.5 K is used… …considered to be cooled. When this study is done it is repeated with only non temperature dependent… …0.6 h when being cooled down to 45 K. Table 5 shows the cool down time simulated for the two… 

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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 28, 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. 28 Sep 2020.

Vancouver:

Olofsson J. Thermo-mechanical analysis of cryo-cooled electrode system in COMSOL. [Internet] [Thesis]. Uppsala University; 2018. [cited 2020 Sep 28]. 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

.