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Pershenkov V.S.,National Research Nuclear University MEPhI | Ullan M.,Campus Universitario Of Bellaterra | Wilder M.,Santa Cruz Institute for Particle Physics SCIPP UCSC | Spieler H.,Lawrence Berkeley National Laboratory | And 7 more authors.
Microelectronics Reliability | Year: 2014

The possible physical mechanism of the anomalous recovery effect in SiGe bipolar transistors is described. The qualitative analysis of saturated oxide trapped charge and interface trap densities at very high total doses as a function of dose rate affords an explain of decreasing excess base current and increasing current gain during further low dose rate irradiation. © 2014 Elsevier Ltd.

Cano-Sarabia M.,Campus Universitario Of Bellaterra | Cano-Sarabia M.,CIBER ISCIII | Angelova A.,University Paris - Sud | Ventosa N.,Campus Universitario Of Bellaterra | And 4 more authors.
Journal of Colloid and Interface Science | Year: 2010

Vesicles prepared by self-assembly of a hydrated mixture of a cationic surfactant (cetyltrimethylammonium bromide) and a lipid (cholesterol) are studied as potential nanocarriers for the delivery of active ingredients. The understanding of the mechanism of the micelle-to-vesicle transition involved in the vesicle formation appears to be crucial regarding the stability of the vesicles as nanovectors. Here, UV-Vis spectroscopy is used to monitor the phase transition from micelles to vesicles promoted by the progressive addition of cholesterol to CTAB micellar solutions. The employed solvatochromic indicator, pinacyanol chloride (PIN), is a cyanine dye that is highly sensitive to the polarity of the medium. The self-assembly between the CTAB and the cholesterol molecules is investigated by means of turbidity (optical density) measurements as well. © 2010 Elsevier Inc.

Ullan M.,Campus Universitario Of Bellaterra | Benitez V.,Campus Universitario Of Bellaterra | Quirion D.,Campus Universitario Of Bellaterra | Zabala M.,Campus Universitario Of Bellaterra | And 11 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2014

AC-coupled silicon strip sensors can be damaged in case of a beam loss due to the possibility of a large charge accumulation in the bulk, developing very high voltages across the coupling capacitors which can destroy them. Punch-through structures are currently used to avoid this problem helping to evacuate the accumulated charge as large voltages are developing. Nevertheless, previous experiments, performed with laser pulses, have shown that these structures can become ineffective in relatively long strips. The large value of the implant resistance can effectively isolate the "far" end of the strip from the punch-through structure leading to large voltages. We present here our developments to fabricate low-resistance strip sensors to avoid this problem. The deposition of a conducting material in contact with the implants drastically reduces the strip resistance, assuring the effectiveness of the punch-through structures. First devices have been fabricated with this new technology. Initial results with laser tests show the expected reduction in peak voltages on the low resistivity implants. Other aspects of the sensor performance, including the signal formation, are not affected by the new technology. © 2014 Elsevier B.V. All rights reserved.

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