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Showing 1 to 15 of 15 for “"Dilution refrigerator"”.
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Constructing and Characterizing a Scanning SQUID Microscope for a Cryogen Free Dilution Refrigerator
… scanning SQUID microscope in a cryogen-free dilution refrigerator. First, I briefly describe basic SQUID theory, how to perform scanning SQUID microscopy, and how to design SQUIDs suited for microscopy. Next, I discuss both the apparatus and method to systematically characterize SQUIDs. I …
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Phase separation in solid mixtures of helium-3 and helium-4
… parameter and peak shape. A new rigid tail dilution refrigerator cryostat is used to study 3 He-4He crystals with 3He concentrations of 0.10,0.20,0.30,0.45,0.60 and 0.70, and melting pressures between 3.0 and 4.3 MPa. The phase separation temperatures determined are in good agreement with …
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Fabrication and measurement of a niobium persistent current qubit
… experimental work on the PC qubit performed at dilution refrigerator temperatures (T [approximately] 12mK). Microwave spectroscopy was used to map the energy level separation between macroscopic quantum states of the qubit system. We measured the intrawell energy relaxation time [tau]d between …
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Exploring The Universe With The Atacama Cosmology Telescope: Polarization-Sensitive Measurements Of The Cosmic Microwave Background
… a temperature near 100 mK by a custom-designed dilution refrigerator insert. Using ACT's six meter diameter primary mirror and diffraction limited optics, ACTPol is able to make high-fidelity measurements of the CMB at small angular scales (l ~ 9000), providing an excellent complement to Planck. …
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Pyrochlore spin ice Dy2Ti2O7: Investigating a platform for magnetic monopolar quasiparticles
… device (""SQUID"")-based magnetometer in a dilution refrigerator was used to search for signatures of monopole excitations in spin ice. From this work, structural, thermal, and magnetic trends were measured in spin ice crystals grown under varying oxygen conditions, and the large effect of …
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Charge dynamics in superconducting double dots
… are measured at sub Kelvin temperatures using a dilution refrigerator. We use radio frequency reflectometry to measure quantum capacitance, which is dependent on the quantum state of the device. We measure the quantum capacitance as a function of gate voltage, and observe capacitance maxima …
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Characterization of Josephson Devices for Use in Quantum Computation
… was initialized by cooling below 50 mK in a dilution refrigerator. In order for quantum mechanical superpositions to be long-lived, it is necessary to isolate the junction from noisy bias leads that originate at room temperature. I studied two types of isolation: an LC filter, and a broadband …
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Quantum control of optically active defects in the solid state
… three consecutive years. Lastly, we upgrade a dilution refrigerator for optical access, and using the spin properties of Cr3+ defects in sapphire (ruby), conduct all-optical thermometry, reaching lattice temperatures as low as 143 mK under continuous laser excitation. We measure the spin …
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Application of compressional cooling to the study of nuclear ordering in solid helium three
… was precooled to about 20 mOK using a continuous dilution refrigerator. Compression was accomplished using liquid He as a pressurizing fluid. Along the melting curve, the pressure and temperature were measured using, respectively, a beryllium copper capacitor and a cerium magnesium nitrate …
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A measurement system for and the measurement system of single particle energies in quantum dots
… were performed using a 3He/4He Kelvinox 25 dilution refrigerator unit at a lattice temperature of TL45mK. Prior to the work detailed in this thesis the lowest effective electron temperature available to quantum transport researchers at Glasgow had been 1.2 Kelvin. This was achieved with the …
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Cooling an electron gas using quantum dot based electronic refrigeration
… Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron gas becomes increasingly decoupled from the lattice in which it resides. Below ~ 1 K the coupling can be weak enough for the electron gas to be significantly elevated in temperature …
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DEVICE DEVELOPMENT AND CHARACTERIZATION FOR SOLID-STATE QUANTUM COMPUTATION
… also studied and improved. The noise level in a dilution refrigerator with $\approx10$ mK base temperature is substantially lowered from $\approx4$ K to $<0.5$ K. Finally, the device design, modeling, and theoretical calculations of integrating the charge stability improved Al/$\rm{AlO}_x$/Al …
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Transport studies of reentrant integer quantum Hall states forming in the two-dimensional electron gas
… <sup>3</sup>He immersion cell in a state-of-art dilution refrigerator which achieves the required stability of ultra-low temperature. With this experimental setup, we are able to observe for the first time very sharp magnetotransport features of reentrant integer quantum Hall states across many …
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Investigation on High-Mobility Graphene Hexagon Boron Nitride Heterostructure Nano-Devices Using Low Temperature Scanning Probe Microscopy
… the existing scanning gate microscopy and the dilution refrigerator. We detailed the design and the implementation of the radio-frequency reflectometry and the specialised tip holder for the integration of the tip and the transmission lines. We demonstrate the capability of imaging local …
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Growth of low disorder GaAs/AlGaAs heterostructures by molecular beam epitaxy for the study of correlated electron phases in two dimensions
… cm<sup>-2</sup>. As a result, heating effects at dilution refrigerator temperatures were negligible and the gap at ν = 5/2 could be tuned continuously with density to a maximum value of 625 mK, the largest reported to date. An unusual evolution of the reentrant integer quantum Hall states as a …