Search results for "Instrumentation"
showing 10 items of 4914 documents
Special interpretation of formal measurement scales for the case of multiple heterogeneous properties
2001
A formal model of measurement is constructed and its components are outlined in this paper. An integrated hierarchical formal four-level structure which allows description of the multiple heterogeneous properties of a complex object under measurement is developed in order to have a uniform tool for the selection of specific scales for the measurement of these properties. A special treatment of a measurement scale defined on the space of the object states is offered, and corresponding structures of basic types of scales are explained permitting to take into consideration distances between relations on these states. Our approach can serve as the uniform formalised basis for development of mea…
Photodimers of cinnamic acid and related compounds. A stereochemical study by electron-impact and field desorption mass spectrometry
1974
The low energy (13 eV) electron-impact and field desorption mass spectra of some photodimers of cinnamic acid and related compounds containing the cyclobutane ring are reported and the fragmentation patterns analysed in order to obtain stereochemical information on the substituent position on the cyclobutane ring. Both symmetrical and asymmetrical splittings of the cyclobutane ring were detected, allowing characterisation of the head-to-head and head-to-tail structures of the title compounds. A ring opening rearrangement of the McLafferty type was also found.
Diode laser spectroscopy of the nu(8) band of the SF(5)Cl molecule.
2003
Abstract Diode laser spectra of SF 5 Cl have been recorded in the ν 8 band region at a temperature of ca. 240 K, a pressure of 0.25 mbar and an instrumental bandwidth of ca. 0.001 cm −1 . Four regions have been studied: a first one in the P -branch (906.849–907.687 cm −1 ), a second one in the Q -branch (910.407–910.944 cm −1 ), and two other ones in the R -branch (913.957–914.556 and 917.853–918.705 cm −1 ). The whole ν 1 / ν 8 dyad of SF 5 35 Cl has been previously recorded in the group of Professor H. Burger in Wuppertal, thanks to a Fourier transform infrared spectrometer [J. Mol. Spectrosc. 208 (2001) 169]. These data have thus been combined with our diode laser ones in the aim of refi…
Simultaneous Noise and Impedance Fitting to Transition-Edge Sensor Data using Differential Evolution
2019
We discuss a robust method to simultaneously fit a complex model both to the complex impedance and the noise data for transition-edge sensors (TES). It is based on a differential evolution (DE) algorithm, providing accurate and repeatable results with only a small increase in computational cost compared to the standard least squares (LS) fitting method. Test fits are made using both DE and LS methods, and the results compared with previously determined best fits, with varying initial value deviations and limit ranges for the parameters. The robustness of DE is demonstrated with successful fits even when parameter limits up to a factor of 5 from the known values were used. It is shown that t…
Development of an Inductive NIS Thermometer
2012
We have studied an inductive readout for normal metal-insulator-superconductor (NIS) tunnel junctions by using on-chip planar inductors and a DC SQUID (superconducting quantum interference device) to develop a sensitive and fast thermometer for studies of nanoscale heat conduction and bolometry. Our initial results show the feasibility of the concept, with a good sensitivity for temperatures below 1 K for aluminum as the superconductor when voltage biased close to the superconductor energy gap. peerReviewed
Method for finding the critical temperature of the island in a SET structure
2008
We present a method to measure the critical temperature of the island of a superconducting single electron transistor. The method is based on a sharp change in the slope of the zero-bias conductance as a function of temperature. We have used this method to determine the superconducting phase transition temperature of the Nb island of an superconducting single electron transistor with Al leads. We obtain $T_\mathrm{c}^\mathrm{Nb}$ as high as 8.5 K and gap energies up to $\Delta_\mathrm{Nb}\simeq 1.45$ meV. By looking at the zero bias conductance as a function of magnetic field instead of temperature, also the critical field of the island can be determined. Using the orthodox theory, we have …
Patterning of Suitable Structures for the Investigation of the Josephson Effect in YBa2Cu3O7/PrBa2Cu3O7 Superlattices
1996
The aim of our work is to investigate the Josephson effect in YBa 2 Cu 3 O 7-δ /PrBa 2 Cu 3 O 7-δ superlattices. In the case of current flow along c axis direction the superlattice forms an array of artificial Josephson junctions where the YBa 2 Cu 3 O 7-δ layers are the superconducting electrodes which are separated but Josephson coupled by the PrBa 2 Cu 3 O 7-δ sheets. In this paper we report on the preparation, characterisation and patterning of the superlattices into suitable structures via standard photolithograpy and lift-off technique.
Microrefrigeration by quasiparticle tunnelling in NIS and SIS junctions
2000
Abstract A solid-state refrigeration method at sub-kelvin temperatures has been developed. It is based on quasiparticle tunnelling between a superconductor and a normal metal, or, between two dissimilar superconducting metals. The refrigerator is fabricated by combining nanolithography and micromachining methods. This technique has been demonstrated in both electron cooling from 0.3 to 0.1 K and in refrigeration of a dielectric platform. We describe a new fabrication method of tunnel junctions in a shadow evaporation configuration using a mechanical mask of silicon nitride.
Refrigeration of a dielectric membrane by superconductor/insulator/normalmetal/insulator/superconductor tunneling
1997
We have applied tunneling of electrons between a normal metal and a superconductor to refrigerate a thin dielectric membrane attached to the normal electrode of a superconductor/ insulator/normal-metal/insulator/superconductor (SINIS) structure. Starting from T≈200 mK, a decrease in temperature of several mK was observed, measured by a separate thermometer on the membrane. It should be straightforward to improve the refrigerator performance to the level of the recently demonstrated SINIS electron cooling method, such that the drop in the lattice temperature would be more than an order of magnitude larger.
Efficient electronic cooling in heavily doped silicon by quasiparticle tunneling
2001
Cooling of electrons in a heavily doped silicon by quasiparticle tunneling using a superconductor–semiconductor–superconductor double-Schottky-junction structure is demonstrated at low temperatures. In this work, we use Al as the superconductor and thin silicon-on-insulator (SOI) film as the semiconductor. The electron–phonon coupling is measured for the SOI film and the low value of the coupling is shown to be the origin of the observed significant cooling effect.