518 research outputs found
The development of sterilizable image dissector tubes Final report, 15 Apr. 1964 - 15 May 1966
Development and fabrication of sterilizable, electrostatic, wide angle image dissectors with bialkali photocathode
Short wide angle, 1-1/2 inch electrostatic image dissector with parallel plate resistive strip electronic multiplier Final report, 22 Feb. 1963 - 1 Nov. 1965
Electron optical imaging system and combination anode-deflection cone for electrostatic image dissector tube - testing and calibratio
One year life test of 1-1/2 inch image dissector Final report
Lifetime performance characteristics testing for image dissector tube under simulated loading condition
Nernst effect in single crystals of the pnictide superconductor CaFe1.92Co0.08As2 and parent compound CaFe2As2
We report a combined study of the Nernst coefficient (v), Hall effect and
thermoelectric power of CaFe2As2 and CaFe1.92Co0.08As2 single crystals. The
absolute value of v in both samples is enhanced, probably due to ambipolar flow
of electron- and hole-like quasiparticles. The onset of spin-density-wave order
in CaFe2As2 causes further rapid rise of the Nernst coefficient. On the
contrary, in the CaFe1.92Co0.08As2 crystal we do not see any feature of v(T),
which could be clearly associated with SDW fluctuations. In this Co-doped
sample there is also no noticeable increase in of v in the vicinity of
superconducting transition, despite the expectation of such due to vortex
movement.Comment: 6 pages, 3 figures; (v2) slight changes and clarifications; to appear
in Phys. Rev.
3D-xy critical properties of YBa2Cu4O8 and magnetic field induced 3D to 1D crossover
We present reversible magnetization data of a YBa2Cu4O8 single crystal and
analyze the evidence for 3D-xy critical behavior and a magnetic field induced
3D to 1D crossover. Remarkable consistency with these phenomena is observed in
agreement with a magnetic field induced finite size effect, whereupon the
correlation length transverse to the applied magnetic field cannot grow beyond
the limiting magnetic length scale L_H. By applying the appropriate scaling
form we obtain the zero-field critical temperature, the 3D to 1D crossover, the
vortex melting line and the universal ratios of the related scaling variables.
Accordingly there is no continuous phase transition in the (H,T)-plane along
the H_c2-lines as predicted by the mean-field treatment.Comment: 8 pages, 4 figure
Multi-band superconductivity in LaFeAsO_{0.9}F_{0.1} single crystals probed by high-field vortex torque magnetometry
To probe manifestations of multiband superconductivity in oxypnictides, we
measured the angular dependence of the magnetic torque in the
mixed state of LaOFFeAs single crystals as a function of
temperature and magnetic fields up to 18 T. The paramagnetic
contribution of the Fe ions is properly treated in order to extract the
effective mass anisotropy parameter from
. We show that depends strongly on both and ,
reaching a maximum value of 10 followed by a decrease towards values
close to 1 as is lowered. The observed field dependencies of the London
penetration depth and suggest the onset of suppression
of a superconducing gap at .Comment: 7 pages, 7 figure
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