Jb. Legrand et al., SPATIAL INHOMOGENEITIES IN THE ENERGY RESPONSE OF A TUNNEL JUNCTION DETECTOR DUE TO PENETRATION OF ABRIKOSOV VORTICES, Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment, 370(1), 1996, pp. 131-132
For the application of superconductive tunnel junctions (STJs) as high
resolution X-ray detectors the homogeneity of the detector response i
s of utmost importance. In this article it is shown how this homogenei
ty is degraded by the penetration of Abrikosov vortices (AVs) into the
junction electrodes. These AVs may exist because of small misalignmen
ts in the parallel magnetic field, which is applied to suppress the Jo
sephson current and Fiske steps. By means of Low Temperature Scanning
Electron Microscopy (LTSEM) the response of the tunnel junction to loc
al energy deposition is mapped and found to be reduced in areas where
AVs are present. On the basis of these experiments the threshold perpe
ndicular field at which vortices start to penetrate the junction is de
rived.