Title

Design and Construction of a Cryostat for Low-Temperature Electrical Resistivity Measurements

Document Type

Oral Presentation

Campus where you would like to present

Ellensburg

Event Website

https://digitalcommons.cwu.edu/source

Start Date

15-5-2019

End Date

15-5-2019

Abstract

The physical properties of materials at low temperature are of great interest in condensed matter physics. While complex or specialized experiments are sometimes required to completely understand these properties, substantial information about the state of a material can be obtained from relatively simple measurements of electrical resistivity as a function of temperature. To perform such experiments, a cryostat to control a sample’s temperature and electronics to measure its resistance are needed. The goal of this research project was to design and construct a cryostat. The experiment is cooled with a commercial closed cycle refrigerator (CCR), which repeatedly compresses and expands helium gas to reach low temperatures. Temperature control is achieved by monitoring the sample’s temperature with a thermometer and controlling the current to a resistive heater with a feedback loop. A puck that thermally connects the sample to the coldest part of the CCR and interfaces the sample with electronics to take resistance measurements was designed and constructed. An efficient wiring layout was also designed to interface the puck, thermometers, and heaters to the control electronics using home-built multiconductor cables and break-out boxes. A LabView program that monitors and controls the temperature as well as facilitates measurements of the resistance of the sample was developed and tested. In this presentation, these designs and the work completed in this long-term instrument development project will be discussed.

Faculty Mentor(s)

Benjamin White

Department/Program

Physics

Design and Construction_Martin.pptx (29143 kB)
Slides for SOURCE 2019 presentation Mattes

Additional Files

Design and Construction_Martin.pptx (29143 kB)
Slides for SOURCE 2019 presentation Mattes

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May 15th, 12:00 AM May 15th, 12:00 AM

Design and Construction of a Cryostat for Low-Temperature Electrical Resistivity Measurements

Ellensburg

The physical properties of materials at low temperature are of great interest in condensed matter physics. While complex or specialized experiments are sometimes required to completely understand these properties, substantial information about the state of a material can be obtained from relatively simple measurements of electrical resistivity as a function of temperature. To perform such experiments, a cryostat to control a sample’s temperature and electronics to measure its resistance are needed. The goal of this research project was to design and construct a cryostat. The experiment is cooled with a commercial closed cycle refrigerator (CCR), which repeatedly compresses and expands helium gas to reach low temperatures. Temperature control is achieved by monitoring the sample’s temperature with a thermometer and controlling the current to a resistive heater with a feedback loop. A puck that thermally connects the sample to the coldest part of the CCR and interfaces the sample with electronics to take resistance measurements was designed and constructed. An efficient wiring layout was also designed to interface the puck, thermometers, and heaters to the control electronics using home-built multiconductor cables and break-out boxes. A LabView program that monitors and controls the temperature as well as facilitates measurements of the resistance of the sample was developed and tested. In this presentation, these designs and the work completed in this long-term instrument development project will be discussed.

https://digitalcommons.cwu.edu/source/2019/Oralpres/59